Using NASA's long-serving Hubble Space Telescope, astronomers have discovered that a stellar explosion in the Milky Way is blasting out cosmic bullets travelling at 20 million miles per hour.

The cosmic explosion in question is V445 Puppis, which erupted in 2000 and is the only known "helium nova" in our galaxy. Though astronomers have been studying V445 Puppis for two decades, much of the phenomena associated with it were shrouded in mystery due to a vast cloud of dusty debris that surrounded this nova.

When this debris finally cleared, a team of researchers was able to peer into V445 Puppis using Hubble, NASA's exoplanet-hunting spacecraft TESS (Transiting Exoplanet Survey Satellite), and the Earth-based Very Large Telescope (VLT), along with an array of other instruments. This allowed them to discover not only the "bullets", clumps of potentially oxygen-rich gas it is firing, but also the true nature of this system. This revealed that V445 Puppis consists of a dead star hungrily feeding on a companion star that is, by itself, a rare find. Thus, this system offers scientists a rare chance to study one of the rarest types of binary systems and one of the rarest cosmic explosions.

"The origin of these 'bullets' is a mystery. We suspect that these originated post-outburst, but 'bullets' of this kind have not been observed in any other nova," team member John Mills, a researcher at the University of Warwick in the UK, said in a statement.

What is a helium nova?

Helium novas like V445 Puppis occur when a white dwarf dead star cannibalistically strips helium-rich but hydrogen-poor matter from a star that has already lost its outer layer of hydrogen, exposing inner layers of helium; forming a rare "helium star." By contrast, "ordinary" novas are explosions triggered by the buildup of stolen stellar matter rich in hydrogen, not helium.

As the material accumulates on the surface of the white dwarf (a type of stellar remnant left behind when stars around the mass of the sun die) it creates runaway pressures and temperatures that eventually trigger a thermonuclear explosion.

When V445 Puppis went nova back in late 2000, it launched vast, twin plumes of debris that resemble butterfly wings. Stretching out for more than a trillion miles, astronomers initially spotted this bipolar outflow in infrared. The nova also spawned a thick disc of dust that completely obscured the binary star system. That cloud persisted for over two decades, preventing astronomers who were investigating the expanding debris from determining what kind of stars the blast originated from.

Once the debris cleared, this team determined that the system contained a helium star, one of only a few thousand of these stripped stellar bodies to be discovered among the billions of stars that populate the Milky Way.

"The culprits behind this galactic eruption have been an enduring mystery over the past 25 years, which is why it is very exciting to confirm that this helium nova was the result of a helium star accreting onto a white dwarf," Mills said.

The findings also revealed cosmic "bullets" that are even more remarkable, as they have never been seen around any other novas. Intriguingly, the team also found that V445 Puppis may be about to go nova again, and this could lead to an entirely different type of cosmic explosion.

Is V445 Puppis about to blow its top again?

Mills found that the white dwarf in V445 Puppis has overcome its stellar indigestion and is once again feeding on its companion helium star.

This is the process that led to the initial helium nova, and could mean that another episode of this rare type of cosmic explosion is soon to occur.

That has implications for our understanding of another type of cosmic eruption, this time a type of supernova called a Type Ia supernova. These occur when white dwarfs overfeed on companions and are completely destroyed by the resultant explosion.

Scientists have long suspected that repeated helium nova eruptions could lead to final Type Ia supernovas.

A new Type Ia supernova would be exciting because these events are so regular in terms of their light emission that they can be used as so-called "standard candles" to measure cosmic distances and gauge the age of the universe.

This means that they can also be employed in the quest to understand how fast the universe's expansion is proceeding, and the influence of the mysterious force called dark energy on this process.

"I look forward to seeing how this result may help us uncover what powers other similar hydrogen-poor astronomical explosions, such as the famous Type Ia supernovas," Mills said.

The team's research was presented this week at the Royal Astronomical Society's National Astronomy Meeting in Birmingham, UK.

PASADENA, California — NASA's new alien-hunting telescope, the Habitable Worlds Observatory (HWO), will be serviceable out in space (and it will have gamma-ray detectors, to boot).

Do you remember seeing NASA's space shuttle astronauts working on the Hubble Space Telescope out in space? Well, it will likely be robots this time around, but NASA is planning for HWO to be serviceable, which means that they will need to figure out a way to work on, repair, and maintain the observatory while it operates roughly a million miles (1.5 million kilometers) away.

"HWO will have to be serviceable to some extent," NASA's astrophysics division director Shawn Domagal-Goldman told Space.com during a session at the American Astronomical Society's (AAS) 248th meeting in Pasadena, California.

From Hubble to HWO

The Habitable Worlds Observatory (HWO) is NASA's next planned flagship space telescope. But what separates it from previous space telescopes like Hubble or the James Webb Space Telescope (JWST) is its purpose: to look for and study rocky, Earth-like planets orbiting sun-like stars. In other words, to find planets that could hold life. The mission won't just hunt for aliens, but rather explore these habitable planets and their atmospheres, expanding our understanding of other worlds while also being used for a variety of astronomical purposes. And by making it serviceable, NASA will not just extend HWO's life, but it will also open the door for future technologies that can be used to enhance the observatory.

Hubble was a unique case. As the space telescope came about at roughly the same time as NASA's Space Shuttle program, and the telescope was designed to function in low-Earth orbit, it was a natural fit that astronauts go out to assemble, repair and maintain the observatory. "There were decisions made early on that the avionics would be modular in a way that astronauts could take the computer out and put a new computer in, or take a gyroscope out and put a new gyroscope in," former NASA astronaut and former NASA Chief Scientist John Grunsfeld, who today works independently as a consultant in the space industry, told Space.com.

However, HWO won't be so close to us. Instead, it will be located nearby L2, or the Sun-Earth Lagrange point 2, a point out in space roughly one million miles (1.5 million kilometers) away where the gravitational pull of the sun and Earth combine to keep objects in the same orbital period as Earth. This position, which is also home for the JWST, allows space telescopes to stay in sync with Earth, making communication easier. It also makes an astronaut mission quite difficult, if not nearly impossible with the technology we have today.

While the JWST was sent out to this distant vantage point without plans for servicing the telescope, HWO will "have to" be serviceable, according to Domagal-Goldman and further confirmed with NASA's press office. Servicing the observatory could look like anything from instrument swaps to regular maintenance or as-needed repairs, but it could also entail assembling the observatory itself. "If the telescope is too large to launch [fully assembled]," Domagal-Goldman added, it might need to be "assembled in space."

When the JWST went to L2, the mission team realized the problem with micrometeorites was a bit bigger than they anticipated. "We've learned that there's more micrometeorites and they're larger than we expected," said Grunsfeld, "and so you might be able to want to put a patch over a sunshield or a patch on a barrel to patch a hole — and, in principle, robotics could do that."

NASA has yet to confirm details about exactly how they plan to service the new observatory, which makes sense as the design of HWO itself is still in flux. But with L2 being so far away, it's logical to assume that it will need to be supported robotically, instead of with astronauts working out in space like with Hubble. We don't know what these future space telescope robot mechanics might look like, but they will have to be very capable to work on such a powerful observatory all the way out at L2.

"This will be by far the most challenging observatory that we've ever built," Grunsfeld said. "It's just remarkable that we are so bold as to think we can do it, and to be really close to showing that we can … so since we're just getting started, this is the time to have the discussion about should it be serviceable or not."

Science is the driving force

In addition to extending HWO's longevity by building it in a way that will allow it to be repaired out in space, making the observatory serviceable will also stretch its science capabilities in ways we can't yet imagine. If we look at Hubble's history, its instruments have been swapped out for newer, better versions over time that have not just allowed the telescope to continue functioning, it has allowed the telescope to evolve with changing technologies. From Hubble's gyroscopes to the Wide-Field Camera 3 swapped out in 2009, the telescope has benefitted from many technological upgrades. With servicing capabilities, the same could be true for HWO.

HWO is still fairly early in its development, and many years from launch (estimated for the 2040s). But NASA is laying the groundwork for this mission with the upcoming flagship mission the Nancy Grace Roman Space Telescope. This mission carries with it a technology demonstration called the Roman Coronagraph Instrument. Essentially an "exoplanet camera," this instrument will block the glare of far-off stars, getting a direct look at the planets in their orbit. Roman will provide a proving ground for this next-gen coronagraph technology. But even if HWO launches with an advanced version of this coronagraph five , 10 or even 15 years following launch there could be even better planet-spotting technology available.

"I'm sure we will be highly motivated if we see a little rocky planet around a nearby star that kind of looks like Earth," Grunsfeld said, "we're going to be highly motivated to send a higher resolution spectrograph, or some different type of detector … up there as fast as we can. So that's the primary driver of servicing, is to be able to put in new scientific instruments."

By making HWO serviceable, NASA will enable the use of future technologies without having to launch entirely new space telescopes to support them. This is a cost-effective method, but it might also enable the deployment of future technologies that might otherwise not have a place to operate out in space.

"Imagine 20 years from now, or 25 years from now, that there'll be a robust space industry doing servicing, such that we could have a commercial servicer deliver new scientific instruments to habitable worlds," Grunsfeld said. They would simply "slide the old ones out, [and slide] the new ones in."

Speaking of future technologies, this decision to make HWO serviceable wasn't all that NASA revealed at AAS. Domagal-Goldman also shared that HWO will be equipped with Gamma-ray detectors. The specific details of these detectors and what they will be used for is also to-be-determined, but with HWO being serviceable, these detectors could continue to evolve with the observatory over time, enabling future astronomy that we can't even imagine today.

On July 4, the United States of America celebrates its 250th birthday, marking the anniversary of the Declaration of Independence and becoming a sovereign nation.

Today, this relatively young country leads the way in our understanding of the universe. It's where many major players in space science, like NASA, the California Institute of Technology (Caltech), the Massachusetts Institute of Technology (MIT), and Northwestern University, to name just a few.

And to celebrate 250 years of the U.S. as an independent nation, Space.com takes you on a journey through some common misunderstandings of the universe through the years and the roles American scientists played in clearing up that cosmic confusion.

By 1776, Sir Isaac Newton's laws of motion had been around for about 89 years since the publication of Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) in 1687. Five of the solar system planets had been discovered by the Ancient Greeks long before the birth of the U.S. Also, after a long struggle and many attempts to stifle this knowledge, humans were made aware that the Earth orbits the sun rather than the other way around, with the final nail in this coffin of misunderstanding laid by Polish astronomer Nicolaus Copernicus in 1543 and Galileo Galilei in 1610, receiving an extra hammer blow from Newton in 1687.

Galileo had also delivered us to the understanding that not only was Earth's place in the solar system unique, but it wasn't even the only planet to possess moons, with the moons of Jupiter, Io, Europa, Ganymede and Callisto discovered in 1610.

Clearly, by the time the U.S. was born we were already beginning to understand the universe and our place within it, but some major misunderstandings still persisted. One of the largest of these surrounded the nature of the sun itself.

The sun as a burning lump of coal

America was formed during the "steam age," a period of industrialization that lasted from 1770 to 1914. This revolution was driven by coal, powering locomotives, ships, and factories, changing the shape of industry, transportation, and manufacturing. At this time, coal was the densest and most powerful fuel source known to humanity, so it is perhaps little wonder that many early scientists theorized the sun was actually a tremendously massive lump of burning coal.

Then, one of the oldest and most prominent scientific periodicals in the world, the U.S.-based Scientific American, wrote a 1863 article that first began the pushback against the sun as a burning lump of coal.

"If the sun were composed of coal, it would last at the present rate only 5,000 years. The sun, in all probability, is not a burning, but an incandescent, body. Its light is rather that of a glowing molten metal than that of a burning furnace. But it is impossible that the sun should constantly be giving out heat, without either losing heat or being supplied with new fuel," the Scientific American article stated. "Assuming that the heat of the sun has been kept up by meteoric bodies falling into it, it is possible from the mass of the solar system to determine approximately the period during which the sun has shone. The limits lie between 100 millions and 400 millions of years."

Though this estimate was still miles out, we now understand that the sun is around 4.6 billion years old; this development came at a time of a geological revolution that was uncovering evidence that our planet was much older than theological estimates of just a few thousand years.

Around 57 years later in 1920, British scientist Arthur Eddington first suggested stars like the sun are actually powered by the nuclear fusion of hydrogen to helium. The idea was published by Eddington in his 1926 book, "The Internal Constitution of the Stars." Twelve years after this, nuclear physicist Hans Bethe formulated the first explanation of this nuclear fusion process, detailing the proton-proton chain reaction and the Carbon-Nitrogen-Oxygen (CNO) cycle.

The idea of the sun as a burning lump of coal finally burnt out 162 years after the formation of the U.S., a chain reaction kick-started by an American publication.

Ether or…?

During the infancy of the U.S. in the 1800s, scientists understood that light is a wave. Applying this to what they knew of other waves, it was logical to presume that light also needed a medium through which it could propagate. This medium would have to be ubiquitous and possess some unique properties to allow light to propagate through it at the speed of light.

Thus, it was proposed that space was filled with a medium called the luminiferous ether, with luminiferous meaning "light-bearing." The fact that this would have to be an invisible and infinite material that doesn't interact with physical objects made the existence of the luminiferous ether highly controversial.

We now know this medium doesn't exist, and that is thanks to two American physicists, Albert A. Michelson and Edward W. Morley, who in 1887 delivered the most important null result in the history of science: disproving the existence of the luminiferous ether.

Should the luminiferous ether exist, then scientists reasoned that as the Earth orbits the sun at around 66,000 miles per hour (106,216 kilometers per hour), our planet should be moving through the ether, which had been deemed to be stationary. That meant Earth must be moving with respect to the stationary ether. And if the ether is the medium through which light waves ripple, this should mean the speed of light differs ever so slightly in the direction Earth is traveling.

Conducted in Cleveland, Ohio, the Michelson–Morley experiment used a piece of kit called a Michelson–Morley interferometer to test differences in speed for a wave of light traveling perpendicular to Earth and one traveling parallel to Earth. Michelson and Morley had expected to observe an interference pattern caused by the differing travel times of the light waves.

That is what happens when light of the same wavelength arrives at a detector at ever so slightly different times, meaning the peaks and troughs of the waves no longer perfectly align. However, to the surprise of the American physicists, no interference was detected. This meant no difference in the travel speed of light, essentially disproving the existence of the ether.

The negation of the luminiferous ether was of vital importance as it opened the door to Albert Einstein's theory of special relativity in 1905 and general relativity in 1915, the latter of which revised our understanding of gravity and led to our knowledge of black holes and gravitational waves well before the experimental observation of such objects.

Other galaxies!

Though scientists realized Earth isn't in the center of the solar system before the birth of the U.S., there was another glaring misconception. It was believed that the Milky Way, first proposed in Immanuel Kant's "Island Universe" theory in 1755, still occupied a unique position in the universe — with the existence of other galaxies a hotly debated topic. The solar system itself was also thought to be at the center of the Milky Way.

In 1785, astronomer William Herschel set about mapping our galaxy, correctly determining the disk-like shape of the Milky Way but incorrectly placing the solar system at its heart. This picture changed in 1918, when American astronomer Harlow Shapley determined that dense groups of stars called globular clusters are centered on a distant core in the direction of the Sagittarius constellation. This placed the solar system off-center in the galaxy. Today we've expanded upon this, moving our planetary system 27,000 light-years away from the Galactic Center and onto one of our galaxy's spiral arms.

It was five years later, in 1923, that the uniqueness of the Milky Way was shattered. Using the 100-inch (2.5-meter) Hooker telescope at the Mount Wilson Observatory, American astronomer Edwin Hubble imaged the Andromeda nebula (Messier 31) and determined that it was at least a million light-years away. Though we now know this distance is closer to 2.5 million light-years, it was still enough to place M31 outside the boundary of the Milky Way.

The fact that the Andromeda nebula is actually the Andromeda galaxy, a distant and separate galaxy from our own, was announced to the public via The New York Times in Nov. 1924. We were no longer alone galactically — but Hubble wasn't done.

The universe is not static

Another assumption at this time was that the universe was static, something supported by Einstein in 1917. However, in 1929, Hubble discovered that the light from distant galaxies was being redshifted. In other words, the wavelengths of light emanating from these sources were being stretched as those wavelengths traveled toward us. This indicated that these galaxies are moving away from us. Convinced of this, Einstein abandoned his model of the static universe.

American scientists weren't done revising our entire picture of the cosmos, however. In 1998, U.S. researchers like Saul Perlmutter, Adam Riess, and Robert Kirshner were part of two international teams of researchers that discovered that not only is the universe expanding, but this expansion is actually speeding up.

Dark energy was introduced as the mysterious force driving this accelerating expansion. It remains today one of the most pressing mysteries of the cosmos.

Possibly by the time the U.S. celebrates its 300th birthday, the mystery of dark matter will have been solved along with other cosmic puzzles such as the nature of dark matter. If this is the case, it is highly likely that U.S. projects like the Hubble Space Telescope, the James Webb Space Telescope, and the upcoming Nancy Grace Roman Space Telescope will put American innovators and scientists at the forefront of these developments, just as their predecessors have been for the last 250 years.

The past 250 years of optical telescopes have seen revolutionary discoveries and technology that the telescope's inventor, a seventeenth century spectacle-maker by the name of Hans Lippershey, maybe wouldn't have believed possible.

When we look back through the annals of telescope history, we find that a significant turning point came, coincidentally, just five years after the United States' Declaration of Independence was christened.

It was back in England, in 1781. William Herschel had just made what was possibly the greatest astronomical discovery the world had seen up to that point: a new planet, Uranus. The fact that Herschel had found a seventh planet from the sun was revolutionary in itself. All the other planets, from Mercury to Saturn, had been known since antiquity, obvious in the night sky to the naked eye.

Uranus, on the other hand, isn't really visible without optical aid, and its discovery illustrated the power of the telescope to dramatically widen our vistas. Moreover, Herschel found the new planet using a 6.2-inch (157-millimeter) reflecting telescope that he had constructed himself. He was looking through it from the back garden of his home in the Somerset city of Bath.

Herschel was a prolific builder of telescopes, polishing and shaping their speculum mirrors. The 6.2-inch telescope was a midget compared to some of his other beasts, including the famous discovery machine that was the 20-foot, or -meter, in focal length telescope with its 18-inch (457-mm) aperture, and the less successful 40-foot (12-meter) telescope.

Herschel proved that telescopes could do serious science. "As a self-taught astronomer, William Herschel transformed the reflecting telescope from what had generally been thought of as a scientific toy into a serious scientific tool," British science historian Robert Smith of the University of Alberta in Canada told Space.com. "At the root of all Herschel's efforts is his telescope building, because he had to build these big telescopes himself."

Refractors and reflectors

Telescopes come in two main forms: the reflector and the refractor.

Reflectors use mirrors to reflect light to a focal point where the eyepiece is located; refractors use lenses to focus light. In the 18th and 19th centuries, British reflectors like Herschel's were the dominant telescope category, as exemplified by those constructed by the likes of Liverpool's William Lassell and Ireland's Third Earl of Rosse, William Parsons. However, across the English Channel in mainland Europe, refractors, which at the time were optically higher quality, were dominant instead.

"You have to distinguish what's going on in Britain with what's going on elsewhere," said Smith.

Lassell built reflectors with apertures of 24 and 48 inches (61 and 122 centimeters). And the great Leviathan of Parsonstown in Ireland is Lord Rosse's own behemoth, still standing today as a UNESCO World Heritage Site. While the likes of Lassell and Lord Rosse were wealthy, self-taught "grand amateur" scientists, in Europe refracting telescopes were used by academics at universities to make precise measurements of the cosmos, from the orbits of double stars to the distance to stars using parallax.

"On the European continent, refractors were used by professional astronomers whose focus was on precision, whereas for Lassell and Rosse the focus was on collecting more light to see fainter objects," said Smith.

In comes the U.S.

Building large refracting telescopes had its challenges and led to a period referred to as the "Telescope Race," where prestige was equally a motivation alongside science. The "race" was won by the 40-inch (one-meter) refractor at Yerkes Observatory in Chicago in 1897, which cost $500,000 at the time (about $20 million in today's money) and was provided by financier Charles Yerkes who made his money developing Chicago's public transport system, often resorting to bribery in order to win franchises.

Businessmen building telescopes was nothing new, of course: William Lassell made fortunes from brewing, but he also used his own telescopes. What was different now was that men wealthy beyond anyone's dreams saw observatories as vanity projects rather than as scientific instruments to use themselves. The introduction of substantial sums of American money provided by wealthy businessmen was a sea change in both the building of telescopes and the fortunes of astronomy in the U.S.

"I have argued that in the 1880s, America was a bit of an astronomical backwater compared to Europe, but by the 1920s the United States had become the leading nation, certainly in terms of observational astronomy," said Smith.

It wasn't just Yerkes. In California, wealthy landowner James Lick founded the Lick Observatory on Mount Hamilton after being dissuaded from his original plan to build a giant pyramid as a monument to himself in downtown San Francisco. Percival Lowell, obsessed with his delusions about canals on Mars, founded the Lowell Observatory in Arizona in 1894. And on Mount Wilson in California, something big was stirring in part thanks to benefactor John Hooker.

Reflectors come of age

Size has always been a driving force, a challenge and a problem for telescope builders. Even today, the Yerkes refractor is still the champion refractor, only rivaled by the one-meter Swedish Solar Telescope on La Palma, but even this is stepped down from 42 inches to 39 inches (107 cm to 99 cm). The issue is twofold: the thicker the lens, the more the incoming light is attenuated and hence the greater the light loss, so you lose any benefits a large lens might provide. Plus, the heavier a lens is, the more it will sag and deform, destroying its ability to focus properly.

This glass ceiling, if you'll pardon the pun, was circumvented by reflecting telescopes following a vital development in the mid-1800s. Herschel and his peers had been using mirrors made from speculum, which is a reflective and slightly toxic (thanks to the small quantities of arsenic added to the copper and tin mix) metal that is prone to tarnishing easily. Herschel had to polish his telescope mirrors frequently to keep them spick and span.

Then in the 1850s scientists Léon Foucault and Carl August von Steinheil figured out a way to add a thin layer of silver to glass, creating mirrors that were much more reflective than speculum, that weighed less and which didn't tarnish. This paved the way for building bigger and better reflectors, fulfilling the promise of the work started by William Herschel.

One key figure in the resurgence of the reflecting telescope around the turn of the 20th century was the astronomical optician George Ritchey, most famous today for being one half of the duo who invented the Ritchey–Chrétien telescope design that is popular with amateur astronomers, particularly planetary imagers, and which is also employed on dozens of professional telescopes including the largest ground-based telescopes currently in operation.

Ritchey had built a 0.6-meter (24-inch) reflector at Yerkes before he was hired by George Ellery Hale, who was the director of Mount Wilson Observatory. On Mount Wilson Ritchey designed a 1.5-meter (60-inch) reflector in 1908 and then what would be the largest telescope in the world at that time, the 2.5-meter (100-inch) Hooker Telescope, made possible thanks to a generous financial gift from John Hooker. The Hooker Telescope saw its first light in 1917.

"If I had to pick one key optician around about 1900, I would pick George Ritchey," said Smith. "Though Ritchey's innovative approach sometimes became too innovative for Hale. Maybe 'firing' is too strong a term, but Ritchey left Mount Wilson because he just didn't get on with Hale."

A revolution in cosmology

Despite the parting of ways, Ritchey's legacy was secure because the Hooker Telescope transformed astronomy and cosmology, thanks to the work of Mount Wilson staff astronomer Edwin Hubble and his colleague and assistant, Milton Humason. Thanks to the sheer resolving power of the Hooker Telescope, Hubble was able to resolve the mysterious spiral nebulae as galaxies in their own right, proving that galaxies other than our Milky Way exist.

He was able to confirm their distance by using the Hooker Telescope to identify individual stars in those galaxies, stars we call Cepheid variables, which have a particular relationship between their period of variation and their peak brightness. The work of Henrietta Swan Leavitt tells us that the longer a Cepheid's period of variability, the brighter they become, and knowing how luminous they should be, Hubble could compare that to how bright they appeared in the night sky through the Hooker Telescope and then deduce how far away they and their galaxies must be. Hubble and Humason later measured the redshifts of these galaxies, finding they are almost all moving away from us and that the cosmos is expanding.

The Hooker Telescope was superseded by the Hale Telescope, named after the Mount Wilson director and which has a 5.1-meter (200-inch) mirror and came into operation on Mount Palomar in 1949. The Hale Telescope remained the largest optical telescope in the world until 1975 and the Soviet Union's six-meter BTA-6 telescope, and this wasn't beaten until 1993 and the construction of the first of the twin 10-meter telescopes of the Keck Observatory on Mauna Kea in Hawaii. At this size, mirrors have to be composed of multiple individual segments rather than being cast as one solid mirror because gravity would otherwise cause the mirror to deform.

During the second half of the twentieth century, astronomers began to identify the best locations for giant optical telescopes, away from the smog and light pollution of cities whose urban sprawl was growing so great that not even Californian mountaintops could escape them. Today, the best telescopes in the world cluster atop Mauna Kea, on numerous peaks in Chile's Atacama Desert, and in the Canary Islands.

How the Hubble Space Telescope democratized astronomy

For the most exceptional views, you can't beat space itself. In orbit above our obscuring atmosphere, or stationed 1 million miles (1.6 million kilometers) away at the L2 Lagrange point, space telescopes enjoy unprecedentedly clear views of the cosmos. The most recent space telescopes include the James Webb Space Telescope and, launching in September, the Nancy Grace Roman Space Telescope, but the most famous of all is of course the Hubble Space Telescope.

Launched in 1990, Hubble continues against all the odds to push the frontiers of science.

"Its output is staggering," said Smith. It has made over 1.7 million individual observations in the past 36 years, and 23,000 research papers based on those observations have been published by a total of nearly 29,000 astronomers.

"This is the democratization of astronomy," said Smith, and it completes a transformation in astronomy over 250 years in the making. Back when the United States was being founded, astronomers were generally lone wolves, self-taught and self-motivated like William Herschel. Then, throughout the nineteenth century astronomy increasingly became the purview of wealthy men, and even moving into the twentieth century, astronomical discovery was confined to a small group.

"For example, in the early 20th century, the only people who had access to the Mount Wilson telescopes were the staff at the Mount Wilson Observatory, and if you were not on staff then you just couldn't use the largest telescopes in the world, so as an observational astronomer you would be at a disadvantage," said Smith.

While this began to change in the latter half of the twentieth century, with organizations such as the European Southern Observatory and the National Optical Astronomy Observatory (now NOIRLab) giving access to telescopes to a wider swathe of people, the Hubble Space Telescope has really spearheaded this democratization.

"People all over the world can use Hubble," said Smith. "It opens up so many possibilities for astronomical research, with thousands of people using it."

From well-heeled enthusiasts to businessmen looking for a legacy, astronomical research has now truly become accessible to people worldwide thanks to the largest telescopes in space and on Earth. Perhaps that is the ultimate achievement of the past 250 years of telescopes.

A bright, dense cluster of hot, massive stars in a galaxy that existed 1.4 billion years after the big bang has been found helping to end the early universe's foggy days during which neutral hydrogen gas was draped across the cosmos, obscuring ultraviolet light from luminous objects.

The cluster was found emitting ultraviolet light in a small but quickly growing galaxy by the Hubble Space Telescope. The presence of this ultraviolet light, and the star-forming history of the cluster producing it, suggests that bursts of star formation contributed to waves of ionizing radiation that gradually cleared out the opaque neutral hydrogen.

In the aftermath of the big bang, the universe was filled with neutral hydrogen gas that is opaque at short wavelengths of light, such as ultraviolet. However, this ultraviolet light was the neutral hydrogen's worst enemy, gradually ionizing the gas across the universe. Once ionized, hydrogen gas cannot absorb ultraviolet light — and so, the cosmos became transparent at those wavelengths.

Because of this, the first billion or so years are called the Epoch of Reionization. It is referred to as "reionization" rather than ionization because, technically, the gas had already been ionized once before during the first 379,000 years after the Big Bang.

While investigating what brought about this epoch, astronomers had identified two chief suspects that could have produced sufficient amounts of ultraviolet light to ionize the neutral hydrogen. One is active supermassive black holes and the other is the first generations of hot, massive stars. The problem is, given that neutral hydrogen is adept at absorbing the ultraviolet light, astronomers have had difficulty tracing that ultraviolet back to its source and identifying which of the two suspects are the main culprit.

In 2023 the James Webb Space Telescope (JWST) made a major breakthrough, finding a galaxy that existed just 900 million years after the Big Bang that was producing enough energy to ionize the neutral gas surrounding it.

Now the Hubble Space Telescope has gone further, detecting ultraviolet light from a galaxy called MXDFz4.4. This ultraviolet light should only be visible if the surrounding gas had already been ionized.

"Observing a galaxy like this was thought to be impossible," said Ilias Goovaerts of the Space Telescope Science Institute (STScI) in Baltimore, who led the discovery, in a statement. "Researchers expected the 'fog' of neutral hydrogen that filled the early universe would be too thick and obscure our view of its ionizing light. Hubble not only spotted that light, but it also helped reveal incredible details about the galaxy's characteristics."

MXDFz4.4 was first identified in the MUSE eXtremely Deep Field (MXDF), with MUSE being the Multi Unit Spectroscopic Explorer on the European Southern Observatory's Very Large Telescope in Chile. The "z4.4" part of its name tells us that the galaxy exists at a redshift of 4.4, meaning that it existed 12.37 billion years ago. As the universe has expanded in the time since then, the ultraviolet light has been redshifted into visible wavelengths that were detected by Hubble.

"Astronomers have found many galaxies that existed at this point in the history of the universe, but we haven't detected ionizing photons from any of them, making MXDFz4.4 one of a kind," said Marc Rafelski, who is the Hubble Deputy Mission Head at STScI.

MXDFz4.4 is 100 times smaller than our Milky Way galaxy but is forming stars ten times faster than our galaxy is. Many of those stars are being born in the tight, luminous cluster producing the ionizing ultraviolet.

The cluster contains "A lot of young, hot, massive stars in a small space [that] do a better job of blasting through opaque gas," said Goovaerts.

Furthermore, by comparing Hubble's observations of MXDFz.4.4 with those of the JWST, which probed for cooler, older stars in the galaxy, Goovaerts and Rafelski's team discovered that the stars in the cluster had formed in bursts, each burst producing fresh quantities of ionizing ultraviolet radiation that helped to clear out more and more of the neutral gas over time. We now see the galaxy about 250 million years after it finished reionizing the surrounding gas. These hot, massive stars in the cluster end their lives after a few million years as supernova explosions, the blast waves and radiation from which can create bubbles in the gas light years across, creating further pathways for ultraviolet light to escape and be detected by Hubble.

The observations seem to nail down the theory that clusters of hot, massive, luminous stars in young galaxies in the early universe played a dominant role in ionizing the universe's neutral gas.

"Hubble's observations of MXDFz4.4 let us test our hypotheses much closer to the Era of Reionization than ever before," said Rafelski. "Finding more galaxies, especially at slightly later cosmic times where larger samples are within reach, would let us refine these measurements and figure out what cleared our view as that era was ending."

The results were published on June 23 in The Astrophysical Journal.

The Hubble Space Telescope has captured a striking image of an irregular dwarf galaxy.

And while this galaxy might be faint and far away, it certainly takes the spotlight in this spectacular new image.

What is it?

23 million light-years away from Earth lies the irregular dwarf galaxy ESO 490-017. Being a dwarf galaxy, it's only about 12,000 light-years across. The use of "only" here might sound strange. After all, one light-year is 5.88 trillion miles (9.46 trillion km). However, while 12,000 light-years is ... a lot ... our own Milky Way galaxy is at least 100,000 light-years across.

In this image from the Hubble Space Telescope, we can see the faint galaxy speckled with stars with a spectacular bright star at the photo's center.

The galaxy has low surface brightness, so the stars in the image's background appear faint and almost hazy. This makes the foreground stars stand out even more, with beaming diffraction spikes emanating outward.

Hidden in the background of this photo is more than just fuzzy stars, however. The red, orange, and even beige spots in the cosmic backdrop of this image aren't just colorful stellar bodies, but rather other galaxies scattered throughout space.

The primary galaxy imaged is found in the constellation Canis Major, which contains Sirius, the brightest star in the night sky.

Why is it incredible?

This image was captured as part of a Hubble observing program studying galaxies and galaxy clusters as well as how they move throughout the universe. While you might think of galaxies as these stoic, far-reaching cosmic structures, they're really constantly on the move.

This image is just one piece of a larger collection of data that scientists have captured with Hubble to better understand the "cosmic flow" of galaxies and other massive structures in the universe.

This image also shows off Hubble's power. While this galaxy is very far away and fairly faint, the portrait captures it clearly, highlighting the galaxy, its stars, and even other galaxies all in one fantastic view.

Astronomers have captured an extraordinary new look at the hidden birthplaces of star clusters, uncovering fresh clues about how galaxies evolve — and how young planets may be shaped by their stellar environments.

Using observations from the James Webb Space Telescope (JWST) and the Hubble Space Telescope, astronomers studied nearly 9,000 young star clusters across four nearby galaxies: Messier 51, Messier 83, NGC 628 and NGC 4449. The newly released images reveal glowing clouds of gas and dust where thousands of stars are actively forming, while also highlighting the JWST's growing ability to uncover hidden galactic structure. Brilliant knots of newborn stars, dark rivers of dust and glowing cavities carved by stellar winds combine to create a vivid portrait of galaxies in constant motion.

While the JWST's infrared vision allowed scientists to peer through thick cosmic dust, Hubble traced older, fully exposed clusters in visible light. Together, the observations allow researchers to study star clusters from their earliest, dust-shrouded stages to fully emerged stellar groups, according to a statement from NASA.

"This work brings together researchers simulating star formation and those working with observations, as well as groups researching planet formation," Alex Pedrini, lead author of the study from Stockholm University and the Oskar Klein Centre in Sweden, said in the statement. "Using Webb, we can look into the cradles of star clusters and connect planet formation to the cycle of star formation and stellar feedback."

By developing simulations that account for stellar dynamics in emerging star clusters, researchers discovered the universe's largest star clusters break free from their birth clouds much faster than expected, dramatically altering their surroundings in the process. The team found that the most massive clusters cleared away their natal gas clouds in about five million years, while smaller clusters took up to eight million years to emerge — a relatively small difference that could influence how star formation unfolds within galaxies over time.

"Simulations of star formation and stellar feedback have struggled to reproduce how star clusters form and emerge from their natal clouds," said Angela Adamo, co-author of the study and Principal Investigator of the FEAST (Feedback in Emerging Extragalactic Star Clusters) program, which collected the observations used in the research as part of a broader effort to investigate how newly formed stars shape the galaxies around them. "These results give us important new constraints on that process."

Once freed from their birth material, these giant clusters unleash intense ultraviolet radiation and stellar winds that heat and disperse nearby gas — a process known as stellar feedback. Because cold gas is the raw material needed to form new stars, stellar feedback can effectively regulate future star formation inside galaxies.

The findings could also reshape scientists' understanding of planet formation. Young planetary systems developing around stars inside these clusters may become exposed to harsh ultraviolet radiation earlier than expected. That radiation can erode the disks of gas and dust surrounding newborn stars, potentially limiting how large planets are able to grow, according to the statement.

Their findings were published May 6 in the journal Nature Astronomy.

NASA's Hubble Space Telescope was on the receiving end of an amazing space photo for a change.

On Friday (April 24), Hubble's 36th birthday, the Colorado-based spatial intelligence company Vantor published a stunning, close-up shot of the telescope that was taken the day before by one of its WorldView Legion Earth-observing satellites.

"Celebrating 36 years of discovery with the Hubble Space Telescope," Vantor wrote in an X post that shared the photo. "For over three decades, Hubble has expanded our understanding of the universe —delivering breathtaking imagery and groundbreaking science that continue to inspire. Proud to support the technologies and teams that make moments like this possible."

The post also gives some details about the image and Hubble itself, which launched to low Earth orbit (LEO) aboard the space shuttle Discovery on April 24, 1990.

For example, the in-space photo was taken from just 34.8 miles (61.8 kilometers) away, providing "an incredible perspective of one of humanity’s most iconic scientific instruments," the X post reads. "With a space sample distance of 4.0 cm [1.6 inches], Hubble’s signature cylindrical body, gleaming thermal shielding, and extended solar arrays are clearly visible, along with the open aperture door at the front of the telescope."

Vantor (previously known as Maxar Intelligence) operates six WorldView Legion satellites, all of which orbit at the same general altitude — around 322 miles (518 km) above Earth. The sharp-eyed spacecraft can resolve features as small as 11.8 inches (30 cm) on their home planet.

The new Hubble shot was captured by WorldView Legion 4, a Vantor spokesperson told Space.com via email. That satellite reached orbit atop a SpaceX Falcon 9 rocket in August 2024, along with WorldView Legion 3. (The other four rode to space on Falcon 9s in May 2024 and February 2025, with two satellites going up on each launch.)

Hubble famously launched to LEO with a flawed mirror, which was fixed by astronauts during a servicing mission in 1993. The telescope has been going strong ever since, capturing amazing imagery of the cosmos that has captivated astronomers and laypeople alike.

Hubble has recently shown signs of its advanced age, but the iconic observatory continues to make important scientific observations and discoveries. NASA has expressed optimism that the telescope can continue operating through 2035.

The Hubble Space Telescope is celebrating its 36th anniversary in space this week with a glimpse into the heart of a major star-forming region, presented in prismatic color.

The Trifid Nebula (also known as Messier 20) is one of the most famous objects in the night sky, attracting amateur astronomers to its location in the constellation of Sagittarius the Archer, set against myriad stars of the Milky Way. Hubble's new view of the Trifid is somewhat different from what skywatchers can see from Earth: the space telescope's 2.4-meter (8-foot) mirror is able to see much closer and in far more detail than any telescope on the ground is capable of achieving.

Hubble's anniversary image presents what is just a small section of the Trifid, at the end of one of the four large dust lanes that extend from the central region of the nebula. Towering columns and sweeping walls of gas and dust dominate the scene. The center point is perhaps what looks like a gigantic mountain with two 'spikes' protruding from its peak, like the antennae on an insect. Yet despite their appearances, these spikes are two completely different phenomena.

The spike pointing straight up is a pillar of denser gas and dust that has not yet been eroded by the barrage of ultraviolet light and powerful particle winds from nearby newborn massive stars that are just beyond the edges of this image. At the tip of the pillar, we can see a star that has formed. Although it is still embedded in the nebula and not clearly visible, we can see what looks a little like the tip of a fingernail around it. This, it seems, is a circumstellar disk that one day will form planets.

The other spike pointing towards the left is very different, with a more cloudy and uneven appearance than the thick pillar. This spike is a Herbig–Haro object (HH 399, specifically) — a jet of material launched by a growing protostar accreting too much matter and ejecting the excess along its rotational axis. The jet bursts out through the clouds of the nebula and extends light-years into space.

Between Hubble's first image of the Trifid taken in 1997 and this new image, astronomers have been able to measure the speed of the jet and see how its size and structure have changed during the intervening 29 years. From this information, they aim to learn in greater detail how young stars interact with their environment, which potentially can impact upon how those young stars mature.

To the left of the 'space slug' we can see a lone tendril of gas separated from the rest. This tadpole-like object is a clump of denser nebulosity that hasn't been completely photo-dissociated by the Trifid's radiation field yet.

Meanwhile, the top left and bottom right corners of the new Hubble image are in stark contrast to one another. You might at first think that it is the bottom right corner that is the clearest region in the image, because it is black.

However, the black that you see is not space — it has barely any stars. Instead it is a supremely dense patch of dusty gas that may be forming stars from within, but from without still appears impenetrable.

It's actually the top left corner that is clearest. The pretty blue hue is produced by ionized gas as ultraviolet light begins to clear away the nebula. We can see this process in action  — the yellow glow around the head of the slug looks like the nebula is fraying, and this is where the denser gas is being eroded by the radiation. Indeed, in star-forming regions such as the Trifid, the radiation sculpts the nebulosity in a way that is somewhat analogous to how wind sculpts rocks in the desert.

The name of the Trifid, which is over 4,000 light-years away, refers to an object that has three lobes. The nebula was given this name by the nineteenth century British astronomer John Herschel, who saw three lobes divided by dust lanes through his telescope. In actuality, the nebula has four lobes  — Herschel's telescope was unable to resolve the fourth dust lane.

This latest image from Hubble forms just one of more than 1.7 million observations that the space telescope has made over the past 36 years since it launched on April 24, 1990. Those observations have spawned about 23,000 research papers written by nearly 29,000 astronomers in total worldwide, and about 1,100 of those papers were written in 2025 alone.

Hubble may be getting old, but it is far too soon to be talking about its legacy  — it is still accomplishing an extraordinary amount of work in the here and now.

A new image captured by the Hubble Space Telescope shows a spectacular nebula in all its glory. (And yes, it does kind of look like a cosmic sea slug.)

Nearly 30 years ago, Hubble looked at the Trifid Nebula. To celebrate the upcoming 36th anniversary of the telescope's launch on April 24, it looked at the nebula once again. And the image it captured is breathtaking.

What is it?

The Trifid Nebula, more formally known as Messier 20, is a star-forming region located about 5,000 light-years away.

The Hubble Space Telescope first looked at this nebula about 29 years ago in 1997. In looking at the nebula again all these years later, Hubble can show us how the nebula itself has changed over time, but it can also reveal new details as Hubble's camera has improved since taking its original image. During the space shuttle mission STS-125 in 2009, a of astronauts installed a better camera on Hubble with a wider field of view and improved sensitivity.

Why is it incredible?

While this is a massive cloud of dust and gas where stars are created, in this new image, the nebula looks a bit like a sea slug, some have pointed out.

In the image, the nebula has a "body" made out of dust and gas and even a "horn" or "antenna" that is actually part of a plasma jet ejected by a young protostar in the nebula.

Stunning new views of Saturn offer the most detailed portrait yet of the ringed planet, showcasing the combined power of NASA's most advanced space telescopes.

Using observations from the James Webb Space Telescope (JWST) and the Hubble Space Telescope, astronomers have created the most comprehensive look at Saturn to date, blending infrared, visible and ultraviolet light into a single, richly layered image, according to a statement from NASA.

"Together, scientists can effectively 'slice' through Saturn's atmosphere at multiple altitudes, like peeling back the layers of an onion," NASA officials said in the statement. "Each telescope tells a different part of Saturn's story, and the observations together help researchers understand how Saturn's atmosphere works as a connected three-dimensional system."

Each space telescope brings a distinct perspective. Hubble captures crisp, long-term visible-light views of Saturn's cloud bands and atmospheric changes, while the JWST peers deeper into the planet's atmosphere in infrared, revealing heat patterns and structures hidden beneath the upper cloud layers.

The Hubble data, captured in August 2024 as part of the long-running Outer Planet Atmospheres Legacy (OPAL) program, was followed about 14 weeks later by Webb observations taken through Director's Discretionary Time, showing Saturn shifting from northern summer toward its 2025 equinox. Saturn's long seasonal cycles — each lasting about seven Earth years — also provide important context for interpreting changes in the planet's atmosphere and rings over time.

Together, the observations present Saturn as a layered and dynamic world. Hubble's visible-light view shows the planet's softly banded atmosphere, while Webb's infrared observations reveal additional structure, including deeper atmospheric layers, a meandering jet stream in the northern mid-latitudes, possible auroral activity, and several storms scattered across the southern hemisphere.

The combined data highlights how Saturn's appearance changes across different wavelengths, offering a more complete view of its atmosphere, according to the NASA statement.

The images also provide complementary views of Saturn's rings. In Hubble's data, the rings, made of water ice, appear bright in reflected sunlight, with clearly defined structure. In Webb's infrared view, the rings shine even more prominently, standing out against the darker background of space and revealing additional detail in the ring system.

Subtle differences between the telescopes' views also reveal ring features like spokes and structure in the thick central region, as well as differing perspectives of the outer ring, which appears thin and sharply defined in Webb's image but only faintly visible in Hubble's, according to the statement.

Seasonal context adds further value to the observations. Hubble's OPAL program has been tracking changes in the outer planets for more than a decade, providing a long-term record of Saturn's atmosphere. The new Webb observations build on that dataset, offering a broader, multiwavelength perspective as the planet continues its progression toward its next equinox.

The new dataset underscores the power of combining multiple observatories. By integrating Webb's infrared sensitivity with Hubble's long-standing visible-light record, scientists can construct a far more complete picture of planetary behavior than either telescope could achieve alone.

As both observatories continue their missions, researchers plan to build on these observations, tracking Saturn's evolving atmosphere, monitoring storm systems and refining models of its complex climate. With this new composite view, Saturn isn't just a distant gas giant — it's a dynamic world whose hidden layers are finally coming into focus.

NASA has released new Hubble telescope images of the Crab Nebula — taken 25 years after the iconic observatory first gazed at the colorful cosmic crustacean.

What is it?

These new images reveal the changing clouds of gases being expelled from the site of a powerful supernova that exploded in the year 1054. It was so bright at the time of its explosion that it was visible during the day.

That supernova left behind the colorful remnant we see today known the Crab Nebula, or Messier 1. It is found 6,500 light-years from Earth in the constellation Taurus.

NASA's Hubble Space Telescope first imaged the nebula in 1999, before the observatory was upgraded with its Wide Field Camera 3. Astronauts on the space shuttle STS-125 mission installed that camera in 2009, giving Hubble much greater resolution.

NASA pointed Hubble at the Crab Nebula again in 2024, revealing filaments of gas moving outward away from the site of the nebula's progenitor supernova at 3.4 million miles per hour (5.5 million kilometers per hour).

Why is it amazing?

Compared with Hubble's 1999 images, the 2024 images reveal changes in the temperature, density and chemical composition of the nebula's gases. Astronomers are now able to study how supernova remnants like this one change over time, and it's thanks to the tenure of the Hubble telescope.

"We tend to think of the sky as being unchanging, immutable," Johns Hopkins University astronomer William Blair said in a NASA statement accompanying the image. "However, with the longevity of the Hubble Space Telescope, even an object like the Crab Nebula is revealed to be in motion, still expanding from the explosion nearly a millennium ago."

NASA's Hubble Space Telescope has captured a rare cosmic moment: a comet breaking apart in real time.

During its routine imaging of the universe, the space telescope spotted an unexpected object called C/2025 K1 (ATLAS), or comet K1 for short. Remarkably, Hubble's observations revealed that the comet's nucleus was actively fragmenting, according to a statement from NASA.

"Sometimes the best science happens by accident," John Noonan, co-author of the study and physics professor at Auburn University, said in the statement. "This comet [was] observed because our original comet was not viewable due to some new technical constraints after we won our proposal. We had to find a new target — and right when we observed it, it happened to break apart, which is the slimmest of slim chances."

Comets are icy, rocky objects from the outer solar system that heat up as they approach the sun, releasing gas and dust to form a glowing coma and tail. They can also break apart when solar heating and gravitational forces overwhelm their fragile structure.

Astronomers observed K1 over three consecutive days, from Nov. 8 through Nov. 10, 2025, and found that it had already begun breaking apart before Hubble turned its gaze toward it. The telescope caught the comet splitting into at least four pieces, each surrounded by its own coma. One fragment appeared to split again during the observations, suggesting the process was still unfolding.

Researchers estimate the breakup began roughly a week earlier, likely triggered by the comet's close approach to the sun, known as perihelion, when heating and stress are at their peak.

K1 was discovered in May 2025 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) survey and is a long-period comet from the distant Oort Cloud, a vast reservoir of icy bodies at the edge of the solar system. These objects are considered relics of the early solar system, preserving material largely unchanged for billions of years. Before fragmenting, K1 was likely a bit larger than an average comet, measuring about 5 miles (8 kilometers) across, according to the statement.

Comets like K1 are often described as "dirty snowballs," made of ice, dust and rock loosely bound together. As they near the sun, ices sublimate into gas, creating jets that can push outward on the nucleus. Combined with internal weaknesses and gravitational stress, these forces can cause the comet to fracture.

But K1's breakup revealed an additional mystery. Ground-based observers did not see the comet brighten immediately after it fragmented, as might be expected when fresh ice is exposed. Instead, there was a delay between the breakup and visible outbursts.

Scientists think this may be because a comet's brightness comes mainly from sunlight reflecting off dust, not ice. Newly exposed ice may first need to develop a thin dust layer that can then be blown off, or heat may need to build beneath the surface before releasing an expanding cloud of dust, according to the statement.

"Never before has Hubble caught a fragmenting comet this close to when it actually fell apart. Most of the time, it's a few weeks to a month later. And in this case, we were able to see it just days after," Noonan said in the statement.

"This is telling us something very important about the physics of what's happening at the comet's surface. We may be seeing the timescale it takes to form a substantial dust layer that can then be ejected by the gas."

Watching a comet disintegrate in real time is extremely rare, as these events are unpredictable and often too faint to observe in detail. Hubble's high-resolution images allowed scientists to track the fragments as they drifted apart, offering an unusually clear view of the process. As those fragments continue to separate and fade, K1 is offering a rare and fleeting window into how some of the solar system's oldest objects evolve.

Their findings were published Feb. 6 in the journal Icarus.

One of NASA's biggest upcoming astrophysics missions has been stopped in its tracks, and the project's leader is blaming mismanagement at the space agency caused by last year's budget confusion.

AXIS, the Advanced X-ray Imaging Satellite, was one of two concepts selected for detailed design studies in NASA’s Astrophysics Probe Explorer program, competing alongside the far-infrared observatory concept PRIMA. AXIS could have replaced NASA's aging Chandra observatory, which has remained a powerhouse of X-ray astronomy since 1999, but the project is coming to an abrupt halt.

An internal email sent on March 9 from AXIS Principal Investigator Christopher Reynolds informed the mission's international team members that NASA Headquarters has ruled the program ineligible for selection, ending the project’s run before its concept study could undergo full technical review.

"NASA's decision was NOT a judgment of the importance of AXIS science," Reynolds said in the email, which was posted to social media. He said that AXIS’ removal from eligibility was tied to disruptions at NASA’s Goddard Space Flight Center (GSFC) in Maryland, which managed the mission during a period of sweeping workforce losses and operational instability throughout 2025.

"The mission formulation process was critically compromised by the seismic shifts occurring in NASA and the Federal government," Reynolds wrote.

One major setback was brought on by the early retirement of Will Zhang, a scientist that NASA describes as a "mirror-making whiz" for space telescopes.

"The key enabling technology for AXIS is these single-crystal silicon mirror assemblies, pioneered by Will Zhang at GSFC," a Goddard scientist familiar with the matter, but not authorized to speak on behalf of NASA, told Space.com. "Will was always intending to retire soon but he took the DRP."

"Our intent, established in the opening days of the Phase A study, was to build three medium-fidelity assemblies," Reynolds told Space.com in an email. "By the time we reached "pens down" on the proposal, we had built one such assembly," he said, but team continued taking hits.

"It seemed like every week there was an announcement that someone was leaving the AXIS team due to retirement or finding a different job, all because of the uncertainty with NASA funding and the truly chaotic environment at GSFC," the scientist said.

The project lost more than 20 GSFC personnel with key expertise as a result of NASA's Deferred Resignation Program (DRP) and reorganizations to align with the 2026 presidential budget request, according to Reynolds' email, and faced further complications caused by the government shutdown last year.

"Work was halted for almost seven weeks when the core GSFC AXIS study team, dominated by NASA civil servants, was furloughed," Reynolds said. NASA later extended the Concept Study Report deadline, but Reynolds wrote that the extension was "inadequate compensation for the disruption and lost time" to address cost and schedule adjustments that had already been identified.

According to the email, Goddard leadership ultimately gave AXIS managers a choice: submit a Concept Study Report with a non-compliant cost and schedule, or don't submit one at all. NASA also apparently rejected the AXIS' team's appeal to bring the design within compliance during discussions normally held during the review process, calling that option "unacceptable," Reynolds said.

Another Goddard scientist not authorized to speak for NASA, speaking on the condition of anonymity, told Space.com that's not how it's normally done. "It is not at all unusual for a mission concept to be off in budget and launch date after their first pass — the first run-through you ask for everything you can possibly imagine, and then you start scoping back into what is more reasonable while still fulfilling the mission requirements," the scientist said. "The 10% they were off by is not bad at all for a first pass, but they did not have time to get additional quotes to bring it down."

They said the blame sits with NASA management.

"Internally, the general consensus is that this is 100% down to Goddard leadership mismanaging this … this has absolutely nothing to do with the AXIS team, the merit of AXIS as a concept in general, and especially not the Goddard scientists, engineers, and project managers who have put their everything into this mission and were held back by management at every step of the way."

NASA said the decision followed the agency's standard science mission selection process, which includes several checkpoints at which mission concepts are evaluated for compliance with established requirements.

"NASA has confirmed the AXIS (Advanced X-ray Imaging Satellite) Probe concept was not compliant with the 2023 Astrophysics Probe Explorer Announcement of Opportunity," an agency official told Space.com in an email, adding that more opportunities for the X-ray astrophysics community will be announced in the coming weeks.

"I am, quite frankly, livid that AXIS ultimately fell victim to the programmatic chaos of 2025," Reynolds told the AXIS team, arguing that the decision did not reflect the scientific importance of the mission.

AXIS was not necessarily the front runner against PRIMA, the X-ray space telescope's competitor in the Astrophysics Probe program, though. "AXIS was always the riskier of the proposed X-ray probes and people in the community were generally surprised they selected AXIS for Phase A," one of the Goddard scientists said. "Some folks believe it was selected because it was the most Chandra-like, and Chandra is old [and] could use replacing."

Reynolds closed his message by wishing "a smooth and speedy path to selection and flight" to PRIMA, which remains under consideration. He also noted that other X-ray astronomy projects, like SMEX and MidEX, can benefit from the research already accomplished by the AXIS team.

Editor's note: This story was updated on March 13 at 10:40 a.m. ET (1500 GMT) to add a statement from AXIS Principal Investigator Christopher Reynolds regarding the completion of one of three silicon mirror assemblies.

All galaxies are dominated by dark matter, an invisible "stuff" that outweighs all of the matter comprising stars, planets, and moons by around five to one. But in some galaxies, dark matter takes this domination to the extreme. Using the Hubble Space Telescope along with the Euclid Space Telescope, astronomers have discovered what seems to be one of the most heavily dark-matter-dominated galaxies ever seen.

This "dark galaxy," officially designated CDG-2, is located around 245 million light-years away. Unlike regular galaxies, which are bright and prominent even across vast cosmic distances, dark galaxies like CDG-2 are faint, nearly invisible and ghost-like thanks to a sparse smattering of stars and their huge quantity of dark matter.

The team behind the discovery of this galaxy found that, unlike standard galaxies, in which dark matter outweighs ordinary matter by a ratio of five to one, dark matter accounts for a staggering 99% of the mass of CDG-2.

Dark matter is effectively invisible, because unlike protons, neutrons, and electrons  — the particles that comprise everyday matter  — whatever composes dark matter doesn't interact with electromagnetic radiation, that's "light" to you and me. Scientists have been able to determine that galaxies are ruled by dark matter, with dense central cores and halos that extend far beyond visible gas and dust, due to the fact that dark matter does interact with gravity.

This gravitational influence then influences visible matter and light, a knock-on effect which astronomers can see. Even so, dark galaxies are extremely tough to detect.

The discovery of CDG-2 began when a team of astronomers investigated tight groupings of stars called globular clusters, which can often indicate the presence of a hidden population of dim stars in their vicinity. This led to the confirmation of ten faint low-brightness galaxies and two dark galaxy candidates.

To confirm the existence of one of these dark galaxies, the researchers turned to Hubble, Euclid, and the Subaru Telescope in Hawaii.

Hubble data confirmed a tight grouping of four globular clusters in the Perseus galaxy cluster, located around 300 million light-years away. Further observations from Hubble, along with data from Euclid and Subaru, revealed a faint glow around these globular clusters, which served as evidence of a hidden, near-invisible galaxy lurking behind these globular clusters. CDG-2 had revealed itself.

"This is the first galaxy detected solely through its globular cluster population," team leader David Li of the University of Toronto, Canada, said in a statement. "Under conservative assumptions, the four clusters represent the entire globular cluster population of CDG-2."

Li and colleagues performed a deeper analysis of CDG-2, finding that it has a brightness equivalent to that of around 6 million sun-like stars. They determined that around 16% of this brightness was accounted for by the overlying globular clusters. The normal matter in this dark galaxy is thought to have enabled star formation in its past, but the team theorizes these stellar bodies have been stripped away by gravitational interactions with other galaxies. The globular clusters used to detect CDG-2 were able to withstand this gravitational interference due to how densely packed with stars they are, leaving them the only tracers of a now ghostly galaxy.

The team's results were published in The Astrophysical Journal Letters.

It's the final act for a star in the constellation Cygnus, some 1,000 light-years away. But this star is not dying without one final show, it appears — and NASA's Hubble Space Telescope has captured the last act in astonishing detail.

The Egg Nebula, so-named for its yolk (the star) surrounded by egg white (clouds of dust and gas), is extraordinarily dynamic, with twin beams of light punching through a series of rippling arcs. Whereas most nebulas glow on their own, thanks to the ionization of gas, the light here comes from the dying star itself, emerging through gaps in its dusty shell.

This Hubble Space Telescope image is not just a beautiful scene, but also a tool scientists can use to study stellar evolution. The Egg Nebula is a pre-planetary nebula — an early form of a planetary nebula, which is a glowing shell of gas and dust shed from a dying sun-like star. And it's "the first, youngest, and closest pre-planetary nebula ever discovered," according to NASA. While planetary nebulae don't have anything to do with planets directly, they do provide the seed material for future star systems that do have planets, much like our own.

Because the pre-planetary stage lasts only a few thousand years, the Egg Nebula provides scientists a chance to watch the ejection process practically in real time. Over time, the star's core will grow hotter and begin ionizing the surrounding gas, causing the nebula to glow in its own light and marking the next stage of evolution.

Early observations have homed in on the symmetrical patterns in the nebula. Because they're so orderly, scientists believe they did not stem from a violent supernova explosion. Instead, they likely indicate "a coordinated series of poorly understood sputtering events in the carbon-enriched core of the dying star," writes NASA. That, of course, warrants further study.

By combining past and recent Hubble observations of the Egg Nebula, researchers have assembled the most detailed portrait yet of its layered structure, offering new clues about how dying stars sculpt the material that will eventually help form future generations of stars and planets.

The Hubble Space Telescope takes a lot of pictures. In fact, NASA estimates Hubble has snapped 1.7 million images since it launched in 1990. But this poses a unique issue: It's almost impossible for scientists to examine all of the images.

With this in mind, a pair of researchers at the European Space Agency (ESA) built an AI model called AnomalyMatch to comb through the vast Hubble Telescope dataset, and the AI managed to discover 1,300 anomalies, or objects with odd appearances. Hundreds of these anomalies have never been documented before.

"This is a powerful demonstration of how AI can enhance the scientific return of archival datasets," Pablo Gómez, one of the ESA researchers who built the model, said in a statement.

Many of these new discovered objects of note actually defy classification, NASA explains. Most showed distant galaxies in flux as they merge and interact in strange ways and scientists specifically point out "galaxies with massive star-forming clumps, jellyfish-looking galaxies with gaseous 'tentacles,' and edge-on planet-forming disks in our own galaxy resembling hamburgers."

A time crunch

The images Hubble gathers represent the largest volume of observational data in the history of astronomy that we can analyze, yet this dizzying amount of information presents a hurdle for human observers to examine. There's just not enough time. That's why it's promising for NASA to say it took less than three days for the team to sift through nearly 100 million image cutouts using AnomalyMatch.

As for how it works? The researchers trained the AI model to detect weird objects through pattern recognition. AnomalyMatch was essentially built to analyze the images in a similar way to how we process visual information inside our brains.

NASA calls this project a significant advancement. It's the first time a systematic search for astrophysical anomalies has been conducted on the entire Hubble Legacy Archive, which spans decades of deep space observation.

"Archival observations from the Hubble Space Telescope now stretch back 35 years, providing a treasure trove of data in which astrophysical anomalies might be found," David O'Ryan, lead author of the research paper, said in another statement.

"The discovery of so many previously undocumented anomalies in Hubble data underscores the tool's potential for future surveys," Gómez said.

Astronomy and Astrophysics published the paper detailing AnomalyMatch and its findings in December of 2025.

The satellites in Amazon's new internet-beaming megaconstellation in low Earth orbit (LEO) are bright enough to disrupt astronomical research, a study has found.

The study — which was posted on the online repository Arxiv on Jan. 12 but has not yet been peer-reviewed — analyzed nearly 2,000 observations of Amazon Leo satellites. It concluded that the spacecraft exceed the brightness limit recommended by the International Astronomical Union (IAU) that aims to ensure harmless coexistence of satellite megaconstellation with astronomical research.

The internet-beaming satellites, orbiting at an altitude of 391 miles (630 kilometers), have an average apparent magnitude of 6.28, which is too dim to be visible to the naked eye, but still bright enough to bother astronomers. In about 25% of observations, the satellites appeared bright enough to be observable without telescopes.

"Bright satellites are particularly troublesome for large-scale astronomical surveys being conducted at ground-based observatories such as the Vera C. Rubin Observatory," study lead author Anthony Mallama, an astronomer at the IAU Center for Protection of the Dark And Quiet Sky, told Space.com in an email. "However, they can also interfere with orbiting observatories like the Hubble Space Telescope."

Mallama and his colleagues have previously studied the brightness of other satellite networks, especially SpaceX's Starlink, which, with around 9,500 satellites, is by far the largest constellation in orbit today. They also observed the giant BlueBird satellite arrays operated by AST SpaceMobile, whose antennas, which cover 690 square feet (64 square meters), make them the brightest artificial objects in the night sky. (And the next-gen BlueBirds are even bigger, with antennas covering nearly 2,400 square feet, or 223 square m).

Mallama noted that satellites in the Amazon Leo constellation (which used to be known as Project Kuiper) are significantly dimmer than the BlueBirds and slightly fainter than most Starlink satellites, which orbit at a lower altitude of around 300 miles (480 km). Mallama, however, added that the Starlink constellation benefits from being in Earth's shadow for most of its orbital time, which makes it less obtrusive.

Future Amazon Leo satellites are expected to orbit at lower altitudes of around 366 miles (590 km), which will further increase their brightness.

John Barentine, an astronomer at the Silverado Hills Observatory in Tucson, Arizona, and a dark sky expert who did not participate in the new study, said that the Amazon Leo satellites appear especially bright during twilight.

Amazon began launching its internet constellation in 2025. So far, only 180 satellites have been placed into orbit, but Amazon plans to grow the constellation to more than 3,200 spacecraft.

Mallama, however, lauded Amazon for its willingness to engage with astronomers and work on reducing the impact of its satellites on the night skies.

"Satellite operators such as Amazon and SpaceX are working with the astronomical community to reduce the brightness of their satellites," Mallama said. "One method is by making the underside of the spacecraft mirror-like so that sunlight is reflected into space rather than scattering to the ground. Another is to orient the satellites' components so that observers on the ground do not see the sunlit sides."

Barentine added that, since the launch of Amazon's first test satellites in 2023, the company's engineers have managed to reduce the amount of light the orbiting satellites reflect to Earth and therefore their visibility in the night sky.

"Amazon Leo is an instance in which the operator established a dialogue with astronomers early in the design phase of their constellation," said Barentine. "It is encouraging to see that this effort has yielded some success."

Astronomers began sounding alarm bells about the impact of satellite megaconstellations on the observations of the universe shortly after the launch of the first batch of SpaceX's Starlink satellites in 2019. Back then, they revealed streaked images, affected by the trails left behind by satellites passing in the view of telescopes. But since then, SpaceX too has worked on reducing the brightness of its satellites.

Still, an earlier report — published by Mallama and his colleagues in the journal Monthly Notices of the Royal Astronomical Society in November 2025 — found that, with the exception of OneWeb satellites, which orbit at higher altitudes of 745 miles (1,200 km), all currently operational internet-beaming constellations, including the Chinese projects Qianfan and Guowang, were exceeding the IAU-recommended brightness limits.

Star formation can feel like a distant, abstract concept, until you see it mapped across a landscape of gas and dust. A recent image from the Hubble Space Telescope looks at the the N159 star-forming complex within the Large Magellanic Cloud, one of the Milky Way's closest companions. That proximity makes it a prime place to watch how stars form in environments that aren't exactly like our own.

What is it?

The image was captured in a parallel field to a recently released Hubble view, showing a neighboring region of the same sprawling complex. Together, images like these help astronomers build a broader picture of what's happening across a giant star factory rather than focusing on only one bright hotspot.

Within the image, thick clouds of cold hydrogen gas arrange themselves into ridges and wispy filaments. The deep red tones come from hydrogen gas that has been energized by the harsh radiation of newly formed stars. Where the glow is brightest, it's a sign that hot, massive young stars have recently become more active.

Where is it?

The N159 star-forming complex lies in in the Large Magellanic Cloud, which is roughly 150 light-years across and lies about 160,000 light-years from Earth.

Why is it amazing?

This recent image captures the rich dynamics of star formation. Massive young stars don't quietly settle in; their intense radiation and powerful stellar winds push outward, hollowing out the surrounding gas. The bubble-like structures and carved cavities in the glowing hydrogen are classic signatures of stellar feedback, the process by which newborn stars reshape the cloud that made them. That feedback can be both destructive and creative. It can blow material away and shut down star formation in one spot, while compressing gas elsewhere and helping new stars ignite.

Images like this one help astronomers better understand the nitty-gritty details of star formation, giving us more clues about the early universe and its first stars.

Want to learn more?

You can learn more about the Hubble Space Telescope and stellar nurseries.

China is getting close to launching a large space telescope to orbit along with its Tiangong space station, and scientists have just completed a full observation simulation in preparation.

The bus-sized Chinese Space Station Telescope (CSST) — also known as Xuntian, or "surveying the heavens" — is being readied for a launch as soon as early 2027. It features a 6.6-foot-wide (2 meters) primary mirror, slightly smaller than that of the Hubble Space Telescope.

Xuntian will, however, be a much more capable sky survey instrument, according to Chinese space officials. It carries a 2.5-billion-pixel camera and boasts a field of view around 300 times larger than the venerable Hubble, surveying the sky from near-ultraviolet to near-infrared wavelengths and delivering high spatial resolution imagery.

As preparations for launch enter the final stages, a collaborative Chinese research team built an end-to-end simulation suite to provide mock observations for both the telescope's optical and other observation systems to replicate expected instrumental and observational conditions and evaluate the telescope's overall performance. The results were published in the journal Research in Astronomy and Astrophysics in early January.

The Chinese Space Station Telescope is expected to make major contributions to a range of fields, including cosmology, the study of galaxies, the evolution of the Milky Way and stars and planets. It could also provide insights into dark matter and dark energy, according to the National Astronomical Observatories under the Chinese Academy of Sciences (NAOC), which led the mock observation study.

After launch on a Long March 5B rocket, Xuntian will fly independently in low Earth orbit, but it will co-orbit with the Tiangong space station. As shown in a video published by China Central Television (CCTV), the spacecraft will be able to dock with Tiangong. Astronauts will then be able to conduct extravehicular activities, or spacewalks, to maintain, repair or even upgrade the observatory, as NASA astronauts did with Hubble five times between 1993 and 2009.

Using the Hubble Space Telescope, astronomers have witnessed an infant star 20 times larger than the sun setting interstellar clouds ablaze. The source of this cosmic conflagration is a stellar jet travelling at an incredible 2.2 million miles per hour (3.5 million kilometers per hour), the fastest outflow of this type ever seen.

This particular outflow is also the longest outflow from a forming star or protostar ever seen by astronomers, stretching out for a staggering 32 light-years. For context, that is around 8 to 10 times as wide as our entire solar system.

The stunning image of this cosmic eruption from Hubble shows two so-called Herbig-Haro (HH) objects designated HH 80 and HH 81, respectively, glowing in neon green and pink. HH 81 is to the upper left of the image, while HH 80 is to the bottom right.

The star illuminating them is IRAS 18162-2048, located around 5,500 light-years away, and the most massive protostar in the entire molecular cloud known as L291.

Protostars like IRAS 18162-2048 are fed by gas that falls to them from the surrounding clouds of gas and dust that originally condensed to form them. This matter can't fall directly to these hungry cosmic infants because it still possesses angular momentum. That means it forms a swirling cloud around the protostar called an accretion disk, which gradually feeds this stellar newborn like a baby bottle.

However, just as human infants are pretty messy, so too are protostars. Powerful magnetic fields channel plasma in accretion disks to the poles of protostars, accelerating it to high-speeds and then blasting it out as jets.

HH objects are created when jets of ionized gas, or plasma, are blasted away from protostars at incredible speeds. These jets strike previously ejected gas, creating shockwaves that heat that gas, causing the bright glows demonstrated by HH 80 and HH 81 in this Hubble image.

First observed by Hubble in 1995, HH 80 and HH 81 are striking examples of HH objects not just due to the size and speed of the jet powering them, but also because this is the only jet astronomers have ever seen being driven by a young massive star and not a young low mass star.

This spectacular image of HH 80 and HH 81 and its capability to allow astronomers to study minute changes in the structure of these incredible cosmic bodies, was only possible thanks to the sensitivity and resolution of Hubble's Wide Field Camera 3.

Thus, this image is further evidence that even after 36 years in service, Hubble is still a vital tool for astronomers.

Stars don't start out fully formed. Instead, they begin when clouds of diffuse gas and dust clump together, becoming denser than their surroundings. Gravity does the rest, pulling material inward until a collapsing knot becomes a compact, warming core: a protostar, still feeding on the cloud that created it.

That's exactly what was seen in a recent image from NASA's and the European Space Agency's (ESA) Hubble Space Telescope, as the star-forming region known as NGC-1333 hosts a protostar as well as other young stellar objects.

What is it?

Protostars are messy and dynamic, gulping down material in spurts and fits and ejecting powerful outflows of wind and jets that punch into the surrounding clouds. The result is a constant push-and-pull between growth and disruption as the star accretes from its disk while simultaneously blasting material away, carving cavities and shaping the environment that neighboring stars and planets will inherit.

In places where the starlight leaks out and bounces off dust grains, it can illuminate a cloud in phenomenon known as a reflection nebula, as two dark stripes flank the bright point of the growing star. According to Hubble researchers, the stripes are the signature of a protoplanetary disk and the disk's shadow cast across the larger envelope of material that still surrounds the young star.

Where is it?

The star-forming region of NGC 1333 is found in the Perseus molecular cloud, roughly 950 light-years away from Earth.

Why is it amazing?

Regions like NGC 1333 are key for astronomers to better understand the nitty-gritty details of star formation. By mapping these areas in both infrared and visible wavelengths of light, different aspects of this scientific process are revealed. Recent work in the broader NGC 1333 area has used high-resolution observation of protostellar jets to read outbursts like "time stamps," which help astronomers connect bursts of activity to changes in the flow of material, showing that star growth is episodic rather than smooth.

Ultimately, understanding how stars form is inseparable from understanding our own beginnings. Every rocky planet, ocean or atmosphere has begun with the same ingredients: gas, dust, gravity and time. Images like this don't just show how stars can form but also reveal how their dynamics help shape the universe around us.

Want to learn more?

You can learn more about stellar nurseries and the Hubble Space Telescope.

Is it a bird? Is it a plane? No, it's the Hubble Space Telescope transiting the sun at around 17,000 mph (27,000 kph).

Astrophotographer Efrain Morales captured the dramatic footage on Dec. 15, 2025, from the city of Aguadilla in Puerto Rico. In the video, the Hubble Space Telescope appears as a tiny, defined silhouette gliding past the sunspot known as AR4308.

The entire event lasted just 1.01 seconds, leaving Morales no margin for error.

The Hubble Space Telescope orbits at an altitude of about 340 miles (547 kilometers), completing one circuit of Earth every 95 minutes. Catching it against the sun requires not only perfect timing but also precise positioning on the ground.

Transit predictions showed that the alignment was visible within a 4.68-mile-wide (7.54 km) corridor on Earth, meaning that anyone wishing to catch the transit would have to be located at exactly the right place. Even then, the telescope took just 1.01 seconds to traverse the sun from Morales' vantage point — a fleeting encounter that could easily be missed without careful planning and high-speed imaging.

To capture this incredible footage, Morales relied on transit-prediction software to calculate the telescope's exact path across the sun, then paired that timing with a high-frame-rate imaging setup. He recorded the footage using a Lunt LS50THa solar scope, mounted on a CGX-L, alongside an ASI CMOS camera and Cemax 2x Barlows — equipment specifically designed for safe, detailed solar observations where every frame counts. (Reminder: Never observe or photograph the sun without such specialized safety gear.)

Unlike the International Space Station, which frequently steals the spotlight during solar transits thanks to its size, Hubble presents a far greater challenge. Measuring about 43 feet (13 meters) long, the iconic space telescope is roughly 10 times smaller than the ISS, making it much harder to resolve against the sun's brilliant surface.

Editor's note: If you snap an astrophoto and would like to share it with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com.

Astronomers and scientists love Betelgeuse because it shines so brightly. While most stars appear as tiny points of light, Betelgeuse is large enough, and close enough, that we can study it in much greater detail. But this red supergiant star is strange, often shifting, dimming and brightening in our night sky.

In July 2025, scientists found a companion star in Betelgeuse's outer atmosphere, which could account for the red supergiant star's odd appearance. Now, using new observations from the Hubble Space Telescope, as well as data from observatories here on Earth, scientists have detected the wake of Betelgeuse's companion star, which is named Siwarha. This new study confirms Siwarha's existence.

"The idea that Betelgeuse had an undetected companion has been gaining in popularity for the past several years, but without direct evidence, it was an unproven theory," study lead author Andrea Dupree, an astronomer at the Center for Astrophysics | Harvard & Smithsonian (CfA), said in a NASA statement on Monday (Jan. 5).

"With this new direct evidence, Betelgeuse gives us a front-row seat to watch how a giant star changes over time," she added. "Finding the wake from its companion means we can now understand how stars like this evolve, shed material and eventually explode as supernovae."

With the combined observations of Hubble and telescopes at the Fred Lawrence Whipple Observatory in Arizona and Roque de Los Muchachos Observatory in the Canary Islands, the researchers spotted a "pattern of changes" in Betelgeuse. They could recognize Siwarha's wake, or trail, because it's composed of material that's denser than the outer-atmospheric gases that surround it.

Every six years, when Siwarha crosses between Betelgeuse and Earth, the trail becomes visible, and due to its density, it changes the spectrum of colors emitted by the various elements in Betelgeuse's atmosphere.

"It's a bit like a boat moving through water. The companion star creates a ripple effect in Betelgeuse's atmosphere that we can actually see in the data," Dupree said. "For the first time, we're seeing direct signs of this wake, or trail of gas, confirming that Betelgeuse really does have a hidden companion shaping its appearance and behavior."

Siwarha will become visible again in 2027, and researchers are already planning new observations for the event.

The new results on Siwarha's wake were presented Monday at the 247th meeting of the American Astronomical Society in Phoenix, Arizona. The study will appear in The Astrophysical Journal.

Using the Hubble Space Telescope, astronomers have discovered a new type of cosmic object, a cloud of dark matter and gas that contains no stars. The object, located around 14 million light-years from Earth at the outskirts of the spiral galaxy Messier 94 (M94), has been nicknamed "Cloud 9."

That's a fitting nickname, given the delight scientists would have if Cloud 9 lives up to its scientific potential. The new object could not only potentially help explain how galaxies formed from gatherings of dark matter in the early universe, but could also grant insights into the very nature of this most mysterious "stuff."

"This cloud is a window into the dark universe," team member Andrew Fox of the Association of Universities for Research in Astronomy/Space Telescope Science Institute (AURA/STScI) for the European Space Agency (ESA), said in a statement. "We know from theory that most of the mass in the universe is expected to be dark matter, but it’s difficult to detect this dark material because it doesn’t emit light. Cloud-9 gives us a rare look at a dark-matter-dominated cloud."

Dark matter is thought to account for around 85% of the "stuff" in the universe, but remains frustratingly invisible because it doesn't interact with electromagnetic radiation such as light. That means scientists can only infer the presence of dark matter via its interaction with gravity and the influence that interaction has on ordinary matter and on light.

Outweighing the particles that comprise the atoms that compose stars, planets, moons, and everything we see around us on a day-to-day basis, dark matter is believed to have had a major influence in the early cosmos and in the shape of the universe as we see it today. This includes the matter that led to the first stars and galaxies coming together in regions of intense gravity where dark matter first gathered.

Such should also be the case with Cloud 9. Within this dark matter-dominated cloud, known as aReionization-Limited Hydrogen I Cloud (RELHIC), hydrogen gas has at least begun to gather  — which would usually trigger stars being born from vast overdense patches in these clouds. However, star formation has failed to get started in the fossil remnant that is Cloud 9, likely because it seems to have failed to gather enough gas for star birth.

"This is a tale of a failed galaxy," team leader Alejandro Benitez-Llambay of the Milano-Bicocca University in Milan, Italy, said in NASA's statement. "In science, we usually learn more from the failures than from the successes. In this case, seeing no stars is what proves the theory right. It tells us that we have found in the local universe a primordial building block of a galaxy that hasn't formed."

Scientists have long theorized that RELHICs like this one exist, but they would have remained theoretical if it weren't for Hubble.

"Before we used Hubble, you could argue that this is a faint dwarf galaxy that we could not see with ground-based telescopes. They just didn't go deep enough in sensitivity to uncover stars," team member Gagandeep Anand of STScI said. "But with Hubble’s Advanced Camera for Surveys, we're able to nail down that there's nothing there."

The discovery of Cloud 9 indicates there may be many more relic-stalled galaxies out in the universe waiting to be uncovered.

"Among our galactic neighbors, there might be a few abandoned houses out there," said team member Rachael Beaton, also from STScI.

RELHICs aren't to be confused with hydrogen clouds around the Milky Way, which scientists have been studying for many years. Cloud-9 is smaller, more compact, and highly spherical, making it look very different from other hydrogen clouds. Its core is composed of neutral hydrogen and is around 4,900 light-years wide, with a mass estimated to be around 1 million times that of the sun. However, the mass of Cloud 9's dark matter has been estimated at around 5 billion solar masses.

The team behind this discovery thinks that Cloud 9 has the potential to become a fully-formed galaxy full of stars at some point in the future, but only if it can gather up to 5 billion solar masses of hydrogen gas. For now, the fact that it lacks stars means that Cloud 9 offers scientists a unique opportunity to study dark matter clouds.

Meanwhile, astronomers will now be paying close attention to future astronomical surveys in the hope of discovering more failed galaxy RELHICs.

The team's research was published in The Astrophysical Journal Letters and was presented at the 247th meeting of the American Astronomical Society in Phoenix on Monday (Jan. 5).

Recently, the James Webb Space Telescope (JWST) took a stunning image of the star cluster known as Westerlund 2, located in a stellar nursery called Gum 29 found within the Carina Nebula. The cluster is 6-to-13 light-years across and has some of the hottest and biggest stars found in the Milky Way.

What is it?

While the Westerlund 2 cluster was the subject of Hubble's 25th anniversary image in 2015, JWST has taken a different view of the area, resulting in what previous telescopes struggled to count: the cluster's faintest members.

The JWST helped uncover for the first time the full population of brown dwarfs in this massive young star cluster, including objects as small as around 10 times the mass of Jupiter.

Brown dwarfs are grouped under the "dwarf" umbrella because they are star-like objects that form from collapsing gas clouds, yet never become big enough to sustain long-term hydrogen fusion like true stars.

Where is it?

The Carina Nebula is located in the Carina constellation, around 20,000 light-years away from Earth.

Why is it amazing?

Finding brown dwarfs in this harsh and brilliant environment is important because it helps astronomers answer a key question: How efficiently are low-mass objects, like brown dwarfs, being made when there's intense radiation in the area? A complete census of the stars in the image lets scientists compare the Westerlund 2 cluster to quieter star-forming regions and test whether extreme conditions change the "mix" of the objects that are formed.

Want to learn more?

You can learn more about the James Webb Space Telescope and star formation.

Recently, the Hubble Space Telescope captured an image of a dwarf galaxy in the constellation Ursa Major. Markarian 178 (Mrk 178) is one of over 1500 "Markarian galaxies," a class defined by their unusually strong ultraviolet emission first catalogued by Armenian astrophysicist Benjamin Markarian.

This small, cloud-like galaxy is dominated by clusters of young, hot, blue stars, yet it also contains a striking red-tinged region. This reddish glow is the signature of something dramatic happening inside: a population of massive, short-lived Wolf–Rayet stars whose powerful stellar winds carve their imprint directly into the galaxy's spectrum.

What is it?

Wolf-Rayet stars are in a brief, turbulent phase of their lives. Having exhausted the hydrogen in their cores, they shed their outer layers in violent stellar winds, producing strong emission lines—particularly from ionized hydrogen and oxygen—that appear red in specialized Hubble filters. Wolf–Rayet stars live only a few million years, so their presence indicates that new stars formed very recently. Yet astronomers were initially puzzled as Mrk 178 has no obvious large neighboring galaxies that could have triggered such activity. It's a puzzle that continues to be a focus for many astronomers.

Where is it?

Mrk 178 is located around 13 million light-years away in the constellation Ursa Major.

Why is it amazing?

Galaxies like Mrk 178 resemble the small, rapidly star-forming galaxies that populated the young cosmos. Studying them today provides clues to how the first galaxies built up their mass and how heavy elements spread through the universe.

As Hubble and ground-based telescopes continue to probe its structure and history, this glittering blue dwarf will help illuminate some of the most powerful forces shaping our cosmos.

Want to learn more?

You can learn more about dwarf galaxies and star formation.

Rapidly growing swarms of satellites around Earth are no longer just a nuisance for ground-based observatories — the reflections they cause are now intruding on space-based telescopes as well, according to new research.

Roughly 15,000 satellites currently circle the planet in vast internet-providing fleets, more than half of them belonging to SpaceX's Starlink network, which has more than 9,000 spacecraft in orbit. In 2023, astronomers reported that some of these satellites were already photobombing images captured by the Hubble Space Telescope, as sunlight glinted off their surfaces leaving bright trails that erase, obscure or mimic genuine cosmic signals.

If every constellation currently filed with regulators were approved and launched, Earth will be encircled by half a million satellites by the end of the 2030s.

"The natural question that comes up is: how many more space telescopes will be affected when all these constellations are launched?" study co-author Alejandro Borlaff, an astrophysicist at NASA's Ames Research Center in California, told Space.com. "This work is the first careful quantification of a potential problem."

Borlaff and his team modeled how future satellite megaconstellations would appear to four space telescopes: Two already operating ones — Hubble and NASA's SPHEREx (short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer), launched in March — and two planned observatories, China's Xuntian telescope, scheduled for a 2026 liftoff, and the European Space Agency's ARRAKIHS mission, expected to launch next decade.

Using orbital data for every registered constellation from the Planet4589 database maintained by astronomer Jonathan McDowell, the researchers simulated roughly 18 months of telescope operations under varying scenarios that ranged from 100 satellites to one million.

If the 560,000 satellites currently planned are deployed, the team found that one in every three Hubble images would contain at least one satellite trail. For SPHEREx, ARRAKIHS, and Xuntian, more than 96% of exposures would be affected. At the million-satellite level, roughly the number of proposals currently pending, contamination rates roughly double, the study reports.

These findings are "truly frightening," Patrick Seitzer, an astronomer at the University of Michigan in Ann Arbor who was not involved in the new study, told Nature. "This is a very important study for the future of space-based astronomy."

Until 2019, the largest commercial constellation, Iridium, operated just 75 satellites in low Earth orbit. Since then, a dramatic reduction in launch costs and the rise of rideshare missions have driven an exponential surge in deployment. The arrival of super-heavy rockets such as SpaceX's Starship, Blue Origin's New Glenn and China's Long March 9 is likely to make large-scale launches even easier, the study notes.

Crucially, image processing cannot fully recover the science lost to satellite contamination, the researchers emphasize. Techniques such as masking can hide a streak, but the cosmic signal underneath cannot be reconstructed.

"That part of the image will be forever lost," Borlaff told Space.com. Photon noise from reflected sunlight wipes out the original data, and no software, AI included, can reconstruct that data, he said, "simply because the information that came from space to the telescope detector is no longer there."

Not everyone agrees with every aspect of the team's modeling. Rafael Guzmán, consortium lead for ARRAKIHS, told Science that while his group shares the serious concern most astronomers have regarding the effects of megaconstellations, the study assumes ARRAKIHS will survey the entire sky, when it will mostly point away from Earth, where satellites are least visible. His team similarly concludes that around 96% of images would bear satellite trails, but a smaller portion of each image would be contaminated, according to the Science story.

One mitigation strategy proposed in the study is placing large satellite constellations below the altitude of space telescopes, where spacecraft spend more time in Earth's shadow and therefore appear dimmer. But Borlaff acknowledges this could increase satellites in lower orbits burn up more frequently due to atmospheric drag, and recent research suggests that materials released during reentry may harm the ozone layer. Lower orbits also make satellites appear brighter to ground-based observatories, potentially shifting the problem rather than solving it.

"This should be discussed from a multi-disciplinary perspective, not just from astronomy," said Borlaff. "We need to carefully evaluate the resources that we have so we can maintain an orbital environment that is useful for both science and industry."

The study notes that efforts to measure the environmental and scientific impacts of megaconstellations are already struggling to keep pace with launch activity, a dynamic reminiscent of the early days of ozone-layer research, when scientists' warnings about chlorofluorocarbons raced against industrial expansion until the historic Montreal Protocol imposed global limits.

When asked whether he is optimistic that meaningful mitigation is possible, Borlaff described himself as an "optimistic pessimist."

"Our results show what will happen if no action is taken, but I am positive that won't be the case," he said.

The Hubble Space Telescope has turned its sharp eye toward a ghostly swirl of stars and gas known as the "Lost Galaxy," given its faint and elusive appearance to stargazers. More scientifically, this galaxy is known as NGC 4535 and its home to lots of stellar activity.

What is it?

In this recent image, the Hubble Space Telescope captured NGC 4535's spiral arms studded with bright blue star clusters: tightly packed families of young, hot stars. Around many of these clusters are soft pink-red glowing areas, which are zones of ionized hydrogen gas known as H II regions. These H II regions act like neon signs advertising recent star formation. Massive, newly formed stars pour out intense ultraviolet radiation and powerful stellar winds, energizing the surrounding gas and making it glow.

Where is it?

The "Lost Galaxy" is found around 50 million light-years away in the Virgo constellation.

Why is it amazing?

This new image is part of a larger effort by astronomers to catalog roughly 50,000 H II regions in nearby star-forming galaxies. BY systematically mapping these glowing clouds in galaxies like NGC 4535, astronomers can better understand where and how stars form, how long star-forming regions last and how newborn stars affect the cold gas from which they came, which is part of NASA's larger PHANGS observing program.

From being a faint smudge on an Earth-based telescope to high-resolution photographs from the Hubble, NGC 4535 is no longer quite so "lost." Instead, it's emerging as a laboratory to understand how galaxies grow their stars.

Want to learn more?

You can learn more about star formation and the Hubble Space Telescope.

Two flagship spacecraft captured striking new images of Interstellar comet 3I/ATLAS, including a surprisingly sharp snapshot from a camera never meant for scientific imaging.

Discovered on July 1 by the NASA-funded ATLAS telescope in Chile, 3I/ATLAS is only the third confirmed visitor from another solar system, following 1I/'Oumuamua in 2017 and comet 2I/Borisov in 2019.

In November, both the European Space Agency's Jupiter-bound JUICE spacecraft and the Hubble Space Telescope captured new views of the fleeting traveler as it raced through the inner solar system, providing valuable clues about the chemistry and dynamics of bodies born around other stars, scientists say.

On Nov. 2, JUICE pointed five of its science instruments at 3I/ATLAS during a planned campaign to study the comet's activity and composition. That high-resolution data won't reach Earth until February 2026, however. The spacecraft is currently using its main high-gain antenna as a heat shield to protect itself from the sun, according to an ESA statement.

"Our JUICE team couldn't wait that long," ESA wrote. Eager for a sneak peek, engineers used the spacecraft's smaller, slower antenna to trickle home just one-quarter of a single frame from JUICE's Navigation Camera (NavCam), a low-resolution imager designed not for science but for navigating JUICE around Jupiter's icy moons after its 2031 arrival.

The resulting grainy teaser reveals the comet's bright nucleus surrounded by a glowing coma of gas and dust. If you look closely, a faint tail stretches upward. That is the comet's plasma tail, created when sunlight ionizes gas released from its warming surface and the solar wind sweeps those charged particles away from the sun, according to ESA.

If you squint harder, you might also spot a subtler dust tail drifting down and to the left. Recent observations show this dust shows slightly atypical properties, hinting that its grain sizes differ from those of local comets, NASA revealed at a news briefing last month.

The snapshot was taken on Nov. 2, just two days before JUICE's closest approach to 3I/ATLAS, when the spacecraft passed about 41 million miles (66 million kilometers) from the comet. Because JUICE observed the comet just after its closest approach to the sun, on Oct. 30, mission scientists expect the full dataset to reveal even more vigorous, sun-driven activity.

Just weeks after JUICE captured its preview, the Hubble Space Telescope turned its Wide Field Camera 3 back toward 3I/ATLAS for a second round of observations on Nov. 30. The comet was then about 178 million miles (286 million kilometers) from Earth and racing across the background stars. Hubble tracked the comet's motion, causing the stars to smear into thin streaks in the image, a second ESA statement read.

Hubble first imaged 3I/ATLAS in July, shortly after its discovery, revealing a teardrop-shaped cocoon of dust streaming from the comet's icy nucleus. The new observations show a bright central core similarly wrapped in a glow of dust, confirming continued activity.

A recent coordinated NASA-led campaign, which drew on dozens of spacecraft and telescopes from Earth orbit to Mars and beyond, hints at unusual chemistry in the comet’s dust, including a higher-than-normal carbon-dioxide–to–water ratio and gas unusually rich in nickel relative to iron. Both findings may point to formation conditions unlike those in our own solar system, NASA scientists said at a November news briefing.

At the briefing, scientists also said 3I/ATLAS has probably spent a very long time drifting through interstellar space. Its incoming speed suggests it may have been born in an ancient planetary system, possibly one that predates our own.

That "gives me goosebumps to think about, frankly," said Tom Statler, the lead scientist at NASA for solar system small bodies.

At the same briefing, Nicky Fox, the associate administrator of NASA's Science Mission Directorate, stressed that 3I/ATLAS poses no threat to Earth. The comet will come no closer than 170 million miles (270 million kilometers) to our planet and will not pass near any planets as it exits the solar system, including when it crosses Jupiter's orbit in spring 2026.

The objects in our solar system, Fox said, "will be just fine."

Located in the constellation Leo, spiral galaxy NGC 3370 has long been a favorite among astronomers. NGC 3370 is part of a small galaxy group that also other galaxies studied by the Hubble Space Telescope. Studying these galaxies together helps astronomers understand how galaxies interact, evolve and influence one another over cosmic timescales.

What is it?

Spiral galaxies are among the most striking and familiar structures in the universe. Characterized by graceful, winding arms that spiral out from a bright central bulge, these systems are rich with both young and old stars, swirling gas and cosmic dust.

The Milky Way, our own galactic home, is one such spiral, and studying other examples like NGC 3370 provides astronomers with clues about how galaxies form and evolve.

Where is it?

Spiral galaxy NGC 3370 is located 90 million light years away in the Leo constellation.

Why is it amazing?

NGC 3370 is home to two types of celestial landmarks that have helped astronomers chart cosmic distances with precision: Cepheid variable stars and Type la supernovas. Cepheids are pulsating stars whose brightness rises and falls in predictable cycles, the longer the period of pulsation, the more luminous they are. Meanwhile, Type la supernovas occur when a white dwarf star undergoes a thermonuclear explosion, reaching nearly the same peak brightness each time.

By comparing how bright these objects appear from Earth with how bright they actually are, astronomers can calculate their distances, and in turn, measure how quickly the universe is expanding. Together, these "standard candles" form the backbone of the cosmic distance ladder, a framework that has shaped our modern understanding of cosmic scale and motion.

Want to learn more?

You can learn more about the Hubble Space Telescope and galaxy formation.

In the constellation Cepheus lies the barred spiral galaxy NGC 6951. Due to its stellar activity, the galaxy has become a favorite for astronomers using the Hubble Space Telescope.

What is it?

Orbiting above Earth's atmosphere, Hubble observes galaxies like NGC 6951 in visible and infrared light, capturing details that ground-based telescopes cannot. Its images have illuminated how galaxies form, evolve and recycle their material through generations of star birth and death.

In Hubble's recent image, NGC 6951 unfurls its graceful spiral arms, covered in red nebulae glowing with hydrogen gas, a key fuel for new stars.

Where is it?

The spiral galaxy NGC 6951 is located 70 million light-years from Earth, in the constellation Cepheus.

Why is it amazing?

Crossing the core of NGC 6951 is a bar of stars, a common feature in elongated spiral galaxies that acts as a kind of galactic conveyor belt, channeling gas inward toward the nucleus. That flow of gas gives rise to one of the galaxy's most captivating features: a circumnuclear starburst ring about 3,800 light years wide that encircles the galactic heart.

Within this ring, the conditions are just right for an intense burst of star formation. The bar funnels cold gas to the central region, where it collects and compresses, triggering the birth of new stars at a significant rate. Using Hubble's data, astronomers have identified more than 80 possible star clusters inside this ring, many less than 100 million years old, though the spiral galaxy itself has likely persisted for over a billion years.

Want to learn more?

You can learn more about the Hubble Telescope and the process of stellar evolution.

Star clusters are among the many objects observed by the Hubble Space Telescope. These gravitationally bound groups of stars often form from the same molecular cloud and come in various types. These clusters help astronomers study stellar evolution, star formation environments and the interplay between stars and interstellar gas and dust.

Recently, the Hubble Space Telescope caught one of these clusters in the Large Magellanic Cloud.

What is it?

The Large Magellanic Cloud (LMC) is considered a satellite galaxy of the Milky Way. It's actually visible to the naked eye from the Southern Hemisphere and is an ideal hub for studying star formation and galactic structures. The LMC is defined as an irregular galaxy, as it lacks the well-defined spiral arms seen in many larger galaxies.

Where is it?

The LMC is located around 150,000 light-years from Earth.

Why is it amazing?

Because its stars are relatively nearby and its chemical makeup differs slightly from that of the Milky Way, the LMC provides astronomers with unique opportunities to compare how stars and galaxies evolve in different environments.

In this image, Hubble peers into the second-largest star forming area of the LMC, known as N11. The picture created is the result of combining observations taken roughly 20 years apart. The older data (from 2002 to2003) used Hubble's Advanced Camera for Surveys, while newer data from Hubble's Wide Field Camera 3 focuses on mapping the dusty gas structures.

Want to learn more?

You can read more about the Hubble Space Telescope and the formation of stars.

Floating high above Earth's atmosphere, the Hubble Space Telescope has captured some of the most breathtaking images ever seen — galaxies colliding, stars being born, and nebulae glowing in cosmic colors. It’s not just a camera in space; it's a time machine, peering billions of years into the past by catching light that’s traveled across the cosmos.

Over the decades, Hubble has become a household name, not just among astronomers but among anyone who's ever looked up and wondered what's out there.

From confirming the existence of dark energy to helping measure the age of the universe, its discoveries have reshaped science textbooks and sparked imaginations worldwide.

Whether you're a seasoned stargazer or just someone who loves a good cosmic mystery, you'll explore the telescope's greatest hits, quirky facts, and the science behind its stunning snapshots. Expect questions that span astronomy, history, and a few surprises that even Hubble itself might not have seen coming.

Try it out below and see how well you score!

A new algorithm capable of transforming ground-based telescope images by removing the blurring effect of the atmosphere to produce as perfect an image as possible has successfully completed tests on the eight-meter Subaru Telescope on Hawaii's Mauna Kea. The next step is to apply it to images from the Vera C Rubin Observatory when it begins science operations later this year.

The revolutionary algorithm was developed by Johns Hopkins mathematician Yashil Sukurdeep.

"We dubbed our algorithm 'Image MM' because, at its core, it relies on the Majorization–Minimization, or MM, method — an elegant mathematical technique that we've adapted in a new way for exploring the cosmos," Sukurdeep said in a statement.

Ground-based telescopes have always been at a disadvantage compared to space-based observatories such as the Hubble and James Webb Space Telescopes because light has to pass through Earth's atmosphere to reach them. The atmosphere distorts light as the result of tiny but ever-present fluctuations in temperature, pressure, the amount of airborne dust and so on. These distortions, which astronomers refer to as "seeing," are what make stars seem to twinkle.

Astronomers are therefore constantly on a quest to improve their ground-based images and get them as close as possible to a telescope's theoretical maximum resolution, known as the Dawes limit. Adaptive optics are one popular technique, which involves shining a laser into the sky to create an artificial guide star and then performing minute adjustments to the shape of the telescope's optics to match the distortions in the guide star and counteract the effects of the seeing.

"Astronomers already have very sophisticated tools to analyze imaging data from telescopes, but they don't remove all the noise, don't remove all the blur and they don’t deal very well with missing pixel values," said Sukurdeep. "Our framework can recover a near-perfect image from a series of imperfect observations."

ImageMM works by modeling how light from objects in the night sky travels through the distorting atmosphere, and then applying this model to images.

"Think of the atmosphere as a restless sheer curtain, constantly shifting and shimmering, so the scene behind it always looks blurred," said Sukurdeep. "Our algorithm learns to see past that curtain, reconstructing the still, sharp image hidden behind it."

So far, the ImageMM algorithm has been tested on the Subaru telescope, returning images sharper and more detailed than what was previously possible with the Japanese-owned observatory.

Now the intention is to use it on images from the Vera C. Rubin Observatory in Chile, particularly because one of Rubin's science objectives is to map the distribution of dark matter in the universe by measuring how the mass of the dark matter subtly warps space, causing the images of galaxies to be weakly gravitationally lensed and therefore appear slightly deformed. The effect of weak gravitational lensing is not as dramatic as the strong lensing that produces wonderful arcs of light stretching around galaxy clusters and multiple images of background galaxies, which means careful observations must be taken in order to detect weak lensing. ImageMM can sharpen Rubin's already impressive images of galaxies, making measurements of weak lensing more accurate.

"When it comes to billion-dollar ground-based observatories, gaining even just a small degree of depth and quality improvement from these observations can be huge," said Tamás Budavári of Johns Hopkins University.

Although space telescopes will still produce better images, they tend to have narrow fields of view, whereas Rubin has a much wider field of view of 3.5 degrees, or about the angular diameter of seven full moons. Therefore, using ImageMM to sharpen Rubin's images will give it a huge advantage even if the quality of Hubble's and James Webb's images are greater overall.

"We'll never have ground truth, but we think this is as close as it currently gets to perfect [for ground-based telescopes]," said Sukurdeep.

A paper describing ImageMM and its test results was published on Sept. 29 in The Astronomical Journal.

Astronomers have long sorted galaxies into types based on their visible structure. Spiral galaxies, like our Milky Way, have a flat disk, winding spiral arms and ongoing star formation. Ellipticals tend toward smooth, featureless ellipsoids with older stellar populations and little cold gas or dust.

Some galaxies, known as irregulars, don't fit neatly into either mold. And some have aspects of both — like the galaxy NGC 2775, which we see in this Hubble Space Telescope image.

What is it?

Hubble's sharp resolution allows observers to pore over the galaxy's details, showing that it has traits of both spiral and elliptical galaxies. Its core appears unusually smooth and gas-poor, traits of elliptical galaxies, while around that core lies a dusty ring peppered with star clusters, bearing more resemblance to a spiral structure.

Where is it?

NGC 2775 lies around 67 million light-years away in the direction of the constellation Cancer.

Why is it amazing?

Galaxies like NGC 2775 allow astronomers to look at the transitional zones between galaxies as they evolve over time. These hybrids of sorts may have faded spiral arms, rings or bars, all remnants of past interactions.

Unfortunately, we are currently only viewing NGC 2775 at one angle, making it difficult to determine its exact shape. This has led some experts to classify it as a lenticular galaxy, which has a combination of spiral and elliptical features. What astronomers also point out, which Hubble wasn't able to capture, is a 100,000-light-year-long hydrogen tail wrapped around the galaxy, suggesting NGC 2775 may have merged with other galaxies in the past.

Want to learn more?

You can read more about the Hubble Space Telescope and galaxy formation.

Hidden within veils of gas and dust lies the brilliant heart of Messier 82 (M82), better known as the Cigar Galaxy. This galaxy has earned its reputation as one of the most energetic star-forming galaxies in the universe.

Recently, the Hubble Space Telescope took this image of the galaxy, showing it buzzing with activity.

What is it?

M82 is classified as a starburst galaxy, because it forms stars at a rate 10 times faster than our own Milky Way galaxy. This accelerated pace of stellar birth powers immense outflows of gas and fuels the growth of super star clusters at its core, which contain hundreds of thousands of stars and shine far brighter than typical star clusters.

By observing M82, astronomers gain unique insights into how these extreme environments give rise to massive stellar nurseries, and how those nurseries evolve over time.

Where is it?

The Cigar Galaxy is located 12 million light-years away in the constellation Ursa Major, or the Great Bear.

Why is it amazing?

M82 has been a popular target for astronomers and their telescopes, due to its high activity. Hubble has observed it many times, and, more recently, the James Webb Space Telescope turned its infrared eye on the Cigar Galaxy to show views of its dynamics in new wavelengths.

The galaxy will continue to help astronomers better understand processes like star formation, stellar winds and super star clusters.

Want to learn more?

You can read more about the Hubble's images and the M82 galaxy.

Anyone hungry for the icy crunch of a Pluto-like body? No? Well, one nearby white dwarf is going all in on a Pluto-esque snack.

According to NASA, the Hubble Space Telescope has spotted a "burned-out star" snacking on a "fragment of a Pluto-like object" that's not too far from Earth — only about 260 light-years away, which is very close when considering the vastness of the cosmos. However, it's not actually the snacking itself that's fascinating, but rather the icy composition of the exo-Pluto. The object appears to be filled with volatiles like carbon, sulphur, nitrogen and oxygen, which indicate the presence of water. According to Hubble data, the exo-Pluto comprises 64% water ice.

"We were surprised. We did not expect to find water or other icy content," Snehalata Sahu of the University of Warwick, who led the analysis of a Hubble survey of white dwarfs, said in a statement. "This is because the comets and Kuiper Belt–like objects are thrown out of their planetary systems early, as their stars evolve into white dwarfs. But here, we are detecting this very volatile-rich material."

This white dwarf was once a sun-like star, but after it burned up its fuel, it collapsed into an extremely dense stellar remnant. Given the dwarf's intense gravitational pull, scientists believe it drew in a Pluto-like planetesimal from its own version of the Kuiper Belt — a region in our solar system filled with icy bodies, from comets to dwarf planets — and tore it apart. What Hubble has captured is just the remaining fragments of the exo-Pluto, something it's uniquely qualified to do with its Cosmic Origins Spectrograph, which analyzes both near- and far-ultraviolet wavelengths.

Studying the white dwarf and the exo-Pluto fragments is like looking into the future of our own solar system. Eventually, the sun will also turn into a white dwarf, pulling in not only planets, but also icy Kuiper Belt objects. "If an alien observer looks into our solar system in the far future, they might see the same kind of remains we see today around this white dwarf," says Sahu.

Next up, the team hopes to use NASA's James Webb Space Telescope to study the white dwarf and the exo-Pluto in infrared light.

The team's research was published in the journal Monthly Notices of the Royal Astronomical Society on Sept. 18.

The spiral galaxy NGC 7456 may appear like other whirling star systems in our universe. But, as a new image from the Hubble Space Telescope reveals, there is far more going on in this galaxy than meets the eye. Behind the patchy spiral arms and glowing clouds of gas lie star-forming areas and a very active galactic core.

What is it?

The recent image brings the fine details of NGC 7456 into focus, including its spiral arms, which are rich with dust that obscure the stars behind them. The pink areas are regions of gas where new stars are starting to form. As the gas responds to the flood of ultraviolet light from these young stars, it glows a signature red that astronomers use to track star formation.

Where is it?

Spiral galaxy NGC 7456 is located more than 51 million light-years away in the constellation Grus, the Crane.

Why is it amazing?

NGC 7456 can act as a cosmic laboratory of sorts for astronomers to track how stars form. By studying these areas, scientists gain insights into how galaxies recycle gas into new generations of stars and planets.

Beyond this, the European Space Agency's XMM-Newton X-Ray observatory also studied this spiral galaxy repeatedly and found mysterious regions known as ultraluminous X-ray sources (ULXs). These compact objects emit far more X-rays than expected for their size. The precise physics behind ULXs remains one of astronomy's enduring puzzles, and each galaxy that hosts them, including NGC 7456, can provide key clues.

Want to learn more?

You can read more about spiral galaxies and X-ray emission.

Recently, the Hubble Space Telescope captured a before-and-after image of a star exploding brightly. With the images one year apart, the contrast shows how bright a supernova is, and how that brightness fades over time.

What is it?

The supernova explosion, designated as SN 2018gv, is found in the spiral galaxy NGC 2525. According to NASA, Hubble began observing the supernova after an amateur astronomer named Koichi Itagaki first detected it in early 2018.

Where is it?

NGC 2525 is approximately 70 million light-years away from Earth.

Why is it amazing?

SN 2018gv is classified as a Type la supernova, a rare type of stellar explosion. Supernovae of this type are also known as "standard candles" because they can reach a consistent peak brightness that astronomers use to calculate distances very precisely. By comparing their known intrinsic luminosity with how bright they appear from Earth, we can determine just how far away these exploding stars are.

Astronomers also use this type of supernova to help study the rate of the universe's expansion, and how it has changed over time. NASA's Roman Space Telescope, which is still under construction, is designed to study explosions like this one to peer even farther back in time than the Hubble Space Telescope to study the universe's expansion rate even more precisely.

Want to learn more?

You can read more about the Hubble Space Telescope and the study of our expanding universe.

Astronomers using the Hubble Space Telescope have discovered that a seemingly ordinary white dwarf star is actually the result of a dramatic stellar merger.

This result, detailed in a new study led by Snehalata Sahu and Boris Gaensicke of the University of Warwick in the U.K., suggests that other "normal-looking" white dwarfs scattered throughout the universe could also have violent pasts.

"It's a discovery that underlines things may be different from what they appear to us at first glance," Gaensicke, study co-author and a professor of physics at the University of Warwick who serves as the principal investigator of the Hubble program, said in a statement. "Until now, this appeared as a normal white dwarf, but Hubble's ultraviolet vision revealed that it had a very different history from what we would have guessed."

The star, named WD 0525+526, is located about 128 light-years from Earth. Though it appeared rather standard at first glance through visible light, further observations using the Hubble telescope revealed telltale signs of a more turbulent origin, the new study reports.

White dwarfs are the dense remnants of stars like our sun that have exhausted their fuel supplies and collapsed into Earth-size objects. Despite their small size, however, they can pack in up to 1.4 times the mass of the sun. Most white dwarfs form from the predictable evolution of single stars nearing the final days of their life cycles, which is a path our own sun is expected to follow in about 5 billion years.

However, WD 0525+526 may have followed a very different path. Instead of forming from one dying star, it appears to have emerged from the violent collision and merger of two stars. This dramatic past, the new study says, left subtle but detectable fingerprints in the white dwarf's atmospheric makeup.

When Gaensicke and his team examined WD 0525+526 with Hubble's ultraviolet instruments, they detected an unusual amount of carbon in the star's atmosphere — a key sign the star was formed in a merger.

Typically, white dwarfs have outer layers of hydrogen and helium that obscure their carbon-rich cores. But in mergers such as this one, the intense collision can strip away much of these outer layers, allowing carbon to rise to the surface. The signals of such stars are difficult to detect in visible light, but become clearer in ultraviolet wavelengths — and that's where Hubble excels.

WD 0525+526 is remarkable even among the small number of white dwarfs known to be merger remnants, according to the statement. It has a surface temperature of nearly 21,000 Kelvin (about 37,000 degrees Fahrenheit) and a mass 1.2 times that of the sun, making it both hotter and more massive than others in this rare category, the study notes.

Because WD 0525+526 appeared completely normal in visible light, astronomers now suspect that many more white dwarfs could be hiding similar explosive origins.

"We would like to extend our research on this topic by exploring how common carbon white dwarfs are among similar white dwarfs, and how many stellar mergers are hiding among the normal white dwarf family," Antoine Bedrad, a researcher at the University of Warwick who co-led the study, said in the statement.

"That will be an important contribution to our understanding of white dwarf binaries, and the pathways to supernova explosions."

This research is described in a paper published Aug. 6 in the journal Nature Astronomy.

Recently, the Hubble Space Telescope caught this stunning image of the Tarantula nebula, the largest and brightest stellar factory in the Large Magellanic Cloud  —  a dwarf galaxy orbiting our own.

What is it?

The Tarantula nebula is home to some of the largest known stars, boasting masses up to 200 times that of our sun.

The Hubble Space Telescope captured a scene on the nebula's fringes where the super star cluster R136 resides. Near R136 lives a rare type of stars known as Wolf-Rayet stars. These massive stars have shed their hydrogen envelopes and unleash fierce stellar winds, influencing their dusty surroundings.

Where is it?

The Tarantula nebula lives approximately 160,000 light-years away in the Large Magellanic Cloud, in the constellations of Dorado and Mensa.

Why is it amazing?

To study the processes happening within the Tarantula nebula, astronomers used an observing program called Scylla, after the Greek monster, to study the clouds of dust and gas around the stars. The program works in tandem with another Hubble initiative known as ULLYSES (Ultraviolet Legacy Library of Young Stars as Essential Standards), which focuses on the giant young stars in both the Large and Small Magellanic Clouds.

Want to learn more?

You can read more about the Tarantula nebula and star formation.

Thanks to the Hubble Space Telescope, we now have the sharpest image yet of the interstellar visitor 3I/ATLAS, showing that it is clearly a comet, with a coma filled with dust particles and the first hints of a tail.

Of course, 3I/ATLAS is no ordinary comet. Discovered on July 1, 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS), 3I/ATLAS is the fastest comet ever seen. Racing in-system at 130,000 mph (209,000 kph), it is hurtling through space so fast that it will escape the sun's gravitational grasp. Its origin is somewhere beyond the solar system, in interstellar space where it has traveled for aeons, being sped up by gravitational slingshots every time it encounters a star. As a result, 3I/ATLAS is just passing through, and will gain another slingshot from our sun to send it on its way back into interstellar space, never to be seen again.

"No one knows where the comet came from," said David Jewitt of the University of California, Los Angeles in a statement. Jewitt was the science lead on the Hubble observations of 3I/ATLAS. "It's like glimpsing a rifle bullet for a thousandth of a second. You can't project that back with any accuracy to figure out where it started on its path."

Even though 3I/ATLAS' origins are shrouded in mystery, astronomers now have the rare chance to learn as much as possible about a comet that was born around another star and is quite possibly older than our solar system.

Comets have four primary components. They all have a solid nucleus. And, when comets get close to the sun, they warm up, causing outgassing that produces a coma around the nucleus as well as two tails — a dust tail left along its path, and an ion tail pointing away from the sun.

The Hubble observations show that 3I/ATLAS' nucleus is shrouded by a coma made from small particles of dust that have been lifted off the interstellar comet's surface. This coma is hiding the nucleus, but, thanks to Hubble's careful observations, astronomers have now placed upper and lower limits on the size of that core. It is potentially as large as 3.5 miles (5.6 kilometers) across, while the smallest it can be is 1,000 feet (320 meters). That's quite a large size range in the context of cometary bodies.

Hubble also saw a dust plume emanating from the sun-facing, warm side of the comet and feeding the coma, plus the barest hints of a dust tail. These are all typical features of a comet that is still 3.8 astronomical units (Earth-sun distances; one AU is about 93 million miles, or 149.6 million km) from the sun. So in that sense, 3I/ATLAS is behaving very much like a comet native to the solar system. So far, only its velocity and hyperbolic trajectory mark it out as different.

Despite being discovered by a network of telescopes designed to spot hazardous asteroids, 3I/ATLAS is no danger to Earth. The closest it will come is 1.8 AU (167 million miles, or 270 million km), and, even when it reaches its closest point to the sun, called perihelion, on Oct. 29, it will barely be closer to the sun than Mars. In fact, after the comet has entered solar conjunction in the sky as seen from Earth and becomes lost in the sun's glare, it will still be visible from Mars, and our spacecraft at the Red Planet will continue to observe it even after it has moved out of sight from Earth. The comet will reappear in Earth's sky in December 2025.

Astronomers aim to track 3I/ATLAS' rise in activity as it gets closer to the sun for as long as possible. As the amount of outgassing ramps up with the sublimation of various ices, spectroscopic observations could perhaps reveal something of the comet's composition. Astronomers could then compare that composition to the native comets of our solar system. For example, a previously discovered interstellar object, 2I/Borisov, was a comet that had a greater abundance of carbon monoxide than the solar system's comets.

3I/ATLAS is the third interstellar interloper to be discovered, with the first, 1I/'Oumuamua coming in 2017 and 2I/Borisov following in 2019. However, it is believed that this trio is just the tip of the iceberg, with some estimates claiming that there could be as many as 10,000 such objects of various sizes passing through the solar system at any one time.

However, because we can't actually see the nucleus of 3I/ATLAS to measure its size exactly, it means that it is not possible to use its discovery to make more accurate predictions about how many interstellar objects there are. For example, we expect there to be more interstellar objects that are closer to 1,000 feet (300 m) in diameter than larger ones of 3 miles (5 km) or so. If 3I/ATLAS were one of the larger ones, then, based on the fact that it is just the third interstellar object that we've discovered, we'd need to revise our estimates of how many 3-mile objects there are. That's because, statistically, we'd be unlikely to have found one as the third interstellar object if objects of that size are very rare.

We can't even use how likely it was that ATLAS would spot 3I/ATLAS as a guide to how many interstellar objects there are, because it was not the size of the nucleus but rather the dust in the coma scattering light and making 3I/ATLAS appear brighter than it otherwise would have that made it visible to the ATLAS telescope network.

However, not even the presence of a comet's coma can hide the secrets of such objects forever. With the Vera C. Rubin Observatory in Chile now almost fully operational, the expectation is that it will find at least one interstellar visitor per year on average, and at greater distances from the sun — for many of them, before they've had the chance to warm up enough for cometary activity to emerge.

"This latest interstellar tourist is one of a previously undetected population of objects bursting onto the scene that will gradually emerge," said Jewitt. "This is now possible because we have powerful sky survey capabilities that we didn't have before. We've crossed a threshold."

These latest findings about 3I/ATLAS have been accepted for publication in The Astrophysical Journal Letters, and a pre-print of the study is available now.

ANCHORAGE, Alaska — The Trump administration has been disrupting the infrastructure of U.S. science over the last few months, its latest blow being a 2026 budget proposal that would cut NASA's science funding in about half. If passed by Congress, this budget would be devastating, scientists say. It would cancel a number of in-development and currently operational missions, lead to significant layoffs and force the shutdown of some astronomy facilities.

"It basically slashes science just about everywhere," Neill Reid, the multi-mission project scientist at the Space Telescope Science Institute (STScI) in Baltimore, said during the 246th meeting of the American Astronomical Society (AAS) here last month. "NASA science is cut by a factor of two; astrophysics is cut by two-thirds."

This situation therefore begs the question: How might Trump's proposed reductions in U.S. science funding domino down to two of the most high-profile astronomy instruments we have, the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST)?

The short (and glass-half-full) answer is that Trump's fiscal year 2026 budget request doesn't outright cancel the JWST or the HST. The reductions suggested for these instruments are also rather modest relative to those suggested for other projects (not to mention the missions that'd be deleted from the roster altogether, like the Jupiter-orbiting Juno spacecraft).

Still, the JWST's funding would go down from the $187 million it was allocated in 2024 to $140 million for 2026 if the budget gets passed. Hubble's funding would go down from the $93.3 million it had in 2024 to $85 million in 2026. And both of these proposed reductions would certainly affect these cosmic imagers.

Less money, fewer stars

To start with the JWST, Reid says a 25% to 35% reduction in operations could be in store for the $10 billion telescope that lives about a million miles away from Earth.

"The operations costs for JWST were set back in 2011; there was a certain amount of optimism that went into some of those," he said. "There's also been inflation; then you have the [President's budget request] that comes in and cuts more."

A slide in Reid's presentation also stated that "inflation and NASA budget issues are [a] significant risk to JWST support starting Oct 2025." That general support would be needed now more than ever, he explained, seeing as how demand for the JWST has only continued to increase ever since it began observing the cosmos in mid-2022.

With regard to Hubble, Reid pointed out that the telescope's budget has remained "flat" for the past 10 years, which means the team has lost about 30% spending power on the spacecraft already due to inflation: "Essentially, we're now at the point where if you cut the budget further, which is what is proposed here, you end up being able to do less."

To be fair, discussions regarding Hubble funding precede the Trump administration's proposed budget cuts — last year, for instance, an independent panel of experts convened to review what the future of Hubble budgets will look like as the telescope faced a possible 10% cut to its budget under the Biden administration. The Hubble Space Telescope's orbit is also naturally getting lower and lower as the years go by; NASA isn't quite sure yet whether a boosting mission is worth the technology, time and effort (though it's not 100% out of the question).

"The main takeaway for Hubble is that she's in great health," Reid said. "There's a high probability of producing great astrophysics into the early 2030s. The orbit is decaying — we know that — but the median estimate of the entry point [into Earth's atmosphere] is September of 2033."

With Trump's proposed Hubble cut, Reid said some of the telescope's instruments would remain "unsupported" in Earth orbit even if they're able to stay online. He said there's work being done at the moment in a sort of "close-out" to make sure Hubble can have as much support as possible, but that the team will be relying on the community to "self-support" while using those particular instruments.

"The bottom line here is, we're not going to do anything about it until we get formal direction from NASA," he said. "We're preparing … but until NASA tells us 'you need to stop doing something,' we're going to keep doing it."

"I think it is up to us to push back and emphasize the importance of NASA science leadership to our representatives," he added. "You can even tell them that science makes America safer, stronger and more prosperous."

It's a sentiment that was echoed by many at the AAS conference, especially because many scientists are being pressured to not speak out by their institutions for fear of retaliation.

Grants, telescope synergy and the White House

For scientists, some of the most serious consequences of Trump's 2026 budget request have to do with grant funding being significantly reduced. Though it's great to have an operational telescope in space, that telescope isn't of much use if scientists can't create instructions for it.

And those instructions stem from scientific studies, which are funded by grants.

"There's also going to be less money that will go into high-level science products in MAST [which is an astronomy data archive]," Reid said, "and there will be less grant funding."

"That's going to affect, basically, things across the board," he added. "We don't have a specific plan here yet. We'll keep the community informed."

Reid also touched on the importance of publicity for both Hubble and JWST science — something that has indeed been affected by Trump cuts already. "Publicity" in this sense refers to, for instance, the article you're reading right now. Media communications from scientific institutions — including NASA, the National Oceanic and Atmospheric Administration (NOAA) and others that have seen reductions in this sector — allow journalists to learn about research timelines, outcomes and hurdles so they can be explained to the public. This is a key aspect of the scientific process.

"Publicity is something that lets the taxpayer know how we are spending money; what we are doing with it," he said.

Additionally, it can't be ignored that a major purpose of science is to further humanity's knowledge and prospects, meaning humanity should know about the discoveries that are fueling this goal. It is only then when scientific observations can lead to breakthroughs in other disciplines, form the next generation of scientists and procure art that cyclically inspires scientists themselves.

"I mean, there's the Universe of Learning. That's a consortium of different organizations we're part of. It provides materials for museums, for planetariums. Their grant finishes at the end of this year. It's not being renewed," Reid said. "This is something that we're going to need to look at critically in the future — make sure that we can still tell people what we do so we have some support out there for continuing doing it."

And in fact, both the JWST and Hubble are veterans at strengthening the bond between scientific research and public discourse. Both can create visual expanses that make the unimaginable universe seem a little more coherent and tangible while somehow normalizing concepts once confined to fantasy.

"There's a strong synergy between what Hubble does at UV [ultraviolet] wavelengths, and what Webb does at near-infrared," Reid said. "I'm still blown away by the fact that we're kind of blasé now about redshift 13 galaxies."

(Redshift 13 galaxies are those that existed over 13 billion years ago, when the cosmos was still in its infancy. Thanks to the JWST, we can literally look at them today.)

"The Rocky World project is putting together the best aspects of JWST and HST," Reid said. "This is an exciting program that really has a good chance of telling us whether M-dwarf planets [those circling red dwarfs, the most common stars in the Milky Way] are a good place to look for signs of life."

He also mentioned how excellent the results can be when the JWST and Hubble team up with the Chandra X-ray telescope — yet another NASA facility on the chopping block. Trump's 2026 fiscal year budget proposal takes Chandra from its allocated $70 million in 2024 to $0 for 2026.

"Habitable Worlds Observatory, Hubble 2.0, is the next big thing that NASA's aiming for. It was not written out of the [President's budget request]. It's still in there, much reduced, but it's still in there.

"That's good."

The Hubble Space Telescope searches the universe to understand how planets, stars, and galaxies form. Recently, it captured this image of a nebula known as GN 04.32.8 within a larger stellar nursery called the Taurus Molecular Cloud.

What is it?

According to the European Space Agency (ESA), the GN 04.32.8 nebula is classified as a reflection nebula, as it does not emit its own light, but instead its clouds of space dust reflect the light of nearby stars.

The reflection nebula is more brightly illuminated around three young bright stars, the centermost being star V1025 Tauri. This star is a variable star, meaning that it's very chaotic and active as it's beginning its stellar evolution.

Where is it?

The Taurus Molecular Cloud, where GN 04.32.8 lies, is in the constellation Taurus, around 480 light-years from Earth.

Why is it amazing?

The Taurus Molecular Cloud is one of the closest and most well-known stellar nurseries, making it an easy place to study how stars are born and evolve.

But it's not the only thing in this picture that's newly formed. Lower down in this image is a small squished orange spot with a dark line through it. It's easy to miss but important to study, as it's a newly formed protostar surrounded by a protoplanetary disk. Because the disk is edge-on to the Hubble Space Telescope, astronomers can zoom in to further study how this disk formed, revealing more about the early universe.

Want to learn more?

You can read more about baby stars and the Hubble Space Telescope's photographs as astronomers continue peering deep into our universe.

New data from the Hubble Space Telescope suggests that Uranus' largest moons are gathering dust — literally.

Uranus, the seventh planet from the sun and home to 28 known moons, is well known for its bizarre tilt. The planet spins almost completely on its side, an oddball orientation that twists its magnetic field into a warped and constantly shifting force, which scientists have long thought would leave visible scars on its moons by bombarding them with charged particles.

However, new Hubble Space Telescope observations of Uranus' four largest moons — Ariel, Umbriel, Titania and Oberon — show no clear signs of the expected radiation damage, Christian Soto of the Space Telescope Science Institute in Maryland, who led the analysis, told reporters on Tuesday (June 10) at the 246th American Astronomical Society (AAS) press conference in Alaska.

Based on data from NASA's Voyager 2 flyby in 1986 and decades of modeling, scientists expected the trailing hemispheres of Uranus' moons — the sides opposite their direction of travel — to be visibly darkened by radiation. The leading sides, by contrast, were expected to remain relatively brighter.

Instead, the researchers found that the two outer moons, Titania and Oberon, are darker on their leading sides, the opposite of what they had predicted. The visible darkening, they say, doesn't come from Uranus' magnetic field at all, but from dust.

Hubble's data points to a slow inward drift of dust from Uranus' distant irregular moons, which orbit between 2.5 to 13 million miles (4 to 20 million kilometers) from the planet. These outer moons are constantly bombarded by micrometeorites, which kick up particles that gradually spiral inward over millions of years, Soto said. As Titania and Oberon travel through this diffuse dust cloud, they accumulate the particles mostly on their leading sides.

"Think of driving very fast on a highway, and bugs are hitting your windshield — that's what we're seeing here," Soto said during the press briefing.

Interestingly, the inner moons Ariel and Umbriel show no significant difference in brightness between their leading and trailing sides — possibly because the drifting dust doesn't reach them, thanks to shielding by Titania and Oberon.

"Dust collection — I didn't even expect to get into that hypothesis," Richard Cartwright, a planetary scientist at the Johns Hopkins University's Applied Physics Laboratory in Maryland, said in a statement. "But you know, data always surprise you."

As for the role of Uranus' powerful magnetic field, researchers now suspect that its effects might be subtler or more complex than previously thought. It may still be interacting with the moons, but not in a way that creates strong contrasts on their surfaces.

"Uranus is weird, so it's always been uncertain how much the magnetic field actually interacts with its satellites," Cartwright said in the statement.

The findings highlight how little we still know about Uranus. Apart from Voyager 2's brief flyby nearly 40 years ago, coincidentally during a rare solar event, no dedicated mission has ever visited the planet.

To learn more, Soto's team has scheduled follow-up observations with the James Webb Space Telescope within the next year. Using infrared imaging, Webb will take a closer look at the same moons, potentially confirming whether dust, radiation or a combination of both is shaping their surfaces.

"Why do we do this?" Soto said at the briefing. "Well, Uranus is weird — so why not?"

The red arc at the center of this Hubble Space Telescope image is a distant galaxy, called HerS 020941.1+001557. It appears to be partially circling another galaxy, SDSS J020941.27+001558.4, and seems to be intersected in part by the curving, red crescent of light of another remote galaxy, SDSS J020941.23+001600.7,

What is it?

The alignment of the three galaxies creates a type of gravitational lens called an Einstein ring.

Gravitational lenses occur when the light from a very distant object bends (or is "lensed") around a massive (or "lensing") object located between Earth and the distant lensed galaxy. When the lensed object and the lensing object align, they create an Einstein ring.

Einstein rings can appear as a full or partial circle of light depending on how precise the alignment is. The effects of this phenomenon only become clear when dealing with curvatures of light on enormous, astronomical scales.

Where is it?

HerS 020941.1+00155 is now 19.5 billion light-years from Earth, but it appears in the image as it did around 11 billion years ago, when the galaxy was 5.5 billion light-years away and its light began the long journey toward Earth through expanding space.

SDSS J020941.27+001558.4 is located some 2.7 billion light-years away.

Why is it amazing?

The partial Einstein ring in this image was identified by a citizen scientist as part of the SpaceWarps project, which asked the public to search for gravitational lenses in images.

Computers can be programmed to recognize gravitational lensing, but the effects can be easily confused for galaxies that look similar to a distorted background galaxy. Also, in order for the computer to run fast enough to analyze lots of images quickly, they have to cut a lot of corners, and this makes them less effective.

Human beings have a remarkable ability to recognize patterns. With a basic understanding of what the distorted images of galaxies that have passed through a gravitational lens look like, participants in the SpaceWarps project can help discover new examples of this amazing phenomenon, as was the situation in this case.

Want to learn more?

You can read more about the SpaceWarps project and the basics of gravitational lensing.

What might look like sparkling wisps of candy floss, or cotton candy, are dusty gas clouds in the Large Magellanic Cloud, a dwarf galaxy, as imaged by the Hubble Space Telescope. The pink, blue and green colors are not only beautiful to look at but can inform the viewer about the many wavelengths that comprise this photo.

What is it?

A part of a nebula in a dwarf galaxy called the Large Magellanic Cloud, the photo by the Hubble Space Telescope shows a gas cloud strewn in front of a star field.

This type of view is made possible by Hubble’s cameras, including the Wide Field Camera 3 (WFC3) that was used to collect the observations for this image. WFC3 has a variety of filters, each of which lets through only specific wavelengths, or colors, of light.

This image combines observations made with five of WFC3's different filters, including some that capture ultraviolet and infrared light that are outside the field of vision for the human eye.

Where is it?

The Large Magellanic Cloud is located 160,000 light-years from Earth in the constellations Dorado and Mensa. It is the largest of the Milky Way’s many small satellite galaxies.

Why is it amazing?

People often wonder if the colors depicted in photos like these match what humans would see if they were to travel to the location.

The specialists who process Hubble's images combine the telescope's raw data to compose multi-colored images like this one. To do so, they assign a color to each wavelength filter. Visible-light observations are typically matched to the color that the filter allows through. As such, shorter wavelengths of light, such as ultraviolet, are usually colored in blue or purple hues, while longer wavelengths, like infrared, are typically shown in shades of red.

This way, the images stay close to reality while adding in new information from the portions of the electromagnetic spectrum that humans cannot see with our eyes alone.

Want to know more?

You can read more about the Large Magellanic Cloud and the Hubble Space Telescope. You can also learn more about how Hubble Space Telescope images are made.

You are face-to-face with spiral galaxy NGC 3596, courtesy of an image captured by the Hubble Space Telescope. British astronomer William Herschel was the first person to see and document the galaxy in 1784.

What is it?

NGC 3596 is a typical spiral galaxy, other than its straight-on orientation when viewed from Earth.

The bright arms of NGC 3596 are comprised of stars, gas and dust. It is that area where the most stars are being formed, as seen by the bright pink regions and young blue stars tracing the galaxy's arms.

Where is it?

NGC 3596 is situated 90 million light-years from Earth in the constellation Leo, the Lion.

Why is it amazing?

Scientists still don't know why galaxies like this one take on this spiral shape, in part because of the sheer diversity of other examples. "Some have clear spiral arms, while others have patchy, feathery arms. Some have prominent bars across their centers, while others have compact, circular nuclei. Some have close neighbors, while others are isolated," NASA officials wrote in a description of NGC 3596.

Today, researchers believe that spiral arms represent a pattern of high-density and low-density areas. Stars, gas, and dust bunch up as they enter a galaxy's spiral arm, before emerging and continuing their journey through the galaxy.

Want to know more?

You can read more about spiral galaxies and learn how they get their "feathers." You can also read about the formation of the arms of our own galaxy, the Milky Way.

Arp 184 or NGC 1961, a skewed or "peculiar" spiral galaxy, is still stunning in this image from the Hubble Space Telescope.

What is it?

One of the 338 formations cataloged by astronomer Halton Arp in 1966 in his "Atlas of Peculiar Galaxies," Arp 184 or NGC 1961 is a skewed, but still spectacular looking, spiral galaxy as imaged by NASA/ESA's Hubble Space Telescope.

Arp 184 was included in the catalog due to its single broad, star-speckled spiral arm that appears to stretch toward Earth. The galaxy’s far side (as relative to us) has only a few wisps of gas and stars, rather than a similarly spectacular spiral arm.

Where is it?

Arp 184 sits about 190 million light-years away from Earth in the constellation Camelopardalis (The Giraffe).

Why is it amazing?

This Hubble image is the product of three Snapshot observing programs, which are brief observations slotted into time gaps between the orbiting observatory's longer studies.

One of the three programs surveyed galaxies listed in the Atlas of Peculiar Galaxies, as well as A Catalogue of Southern Peculiar Galaxies and Associations, a similar catalog compiled by Halton Arp and Barry Madore.

The remaining two Snapshot programs looked at the aftermath of fleeting astronomical events like the four known supernovae that Arp 184 has hosted in the past three decades.

Want to know more?

You can see another Hubble image of NGC 1961 and view another peculiar galaxy in the Arp catalog. You can also read how the Hubble Space Telescope's capabilities compare today to newer observatories.