Since its launch in 1990, the Hubble Space Telescope (HST) has provided a dazzling array of images that have awed and inspired the public. More than just pretty pictures, the more than 45 terabytes of data collected has provided insight into the universe, from objects as close as the moon to the most remote galaxies, with incredible photos of supernovas and nebulas in between. Below we explore the history of the telescope and its discoveries, plus Hubble facts and links to some of the orbiting observatory’s best pictures. First, we take a look at an iconic photo. No Hubble picture is more widely recognized than the view of the so-called Pillars of Creation within the Eagle Nebula. [See a gallery of recent Hubble pictures.]
Hubble history: From major flaw to perfection
When Galileo first turned a spyglass to the heavens in 1610, he had trouble making out the rings of Saturn that are visible in inexpensive telescopes today. Advances in optics improved scientists' views of the planets, stars, and distant galaxies, but Earth's atmosphere still blocked much of the light for observers on the ground. Larger telescopes were (and still are) placed on high mountains, where thinner atmospheres allow clearer pictures.
In 1923, German scientist Hermann Oberth first suggested that a telescope could be launched into orbit to help overcome the distortions caused by the atmosphere. As rocket launchings became more commonplace, the idea became feasible, and in 1969, approval was given for the launch of a Large Space Telescope. But its development took longer than preparing for a trip to the moon.
In 1975, the European Space Agency began to work with NASA on the plan that would eventually become Hubble. Congress approved funding for the telescope in 1977. The birth of the reusable Space Shuttle provided a new mechanism for delivering such a telescope into space.
The Large Space Telescope was renamed the Hubble Space Telescope (HST) in honor of Edwin Hubble, an American astronomer who, among other things, determined that the universe extended beyond the borders of Milky Way. The world’s first space telescope was then launched on April 24, 1990. The effort cost $1.5 billion, but there would be ongoing costs — both expected and unexpected.
There was a big problem right off the bat. Hubble had a flawed mirror, researchers learned when the telescope reached orbit and was put to work. The images were fuzzy — close to useless. Hubble's main mirror had a major defect, a spherical aberration caused by a manufacturing error. The flaw was just 1/50th the thickness of a sheet of paper.
It took three years before NASA could mount a repair mission. On Decc. 2, 1993, the Space Shuttle Endeavor ferried a crew of seven to fix Hubble during five days of spacewalks. Two new cameras, including the Wide-Field Planetary Camera 2 (WFPC-2) — which later took many of Hubble's most famous photos — were installed during the fix. In December 1993, the first new images from Hubble reached Earth. And they were breathtaking.
Hubble has been serviced five times. Astronauts had to replace batteries and directional gyroscopes, among other fix-it projects. Its final servicing mission took place in 2009 (gallery). The telescope is expected to continue to function until 2014. NASA plans to replace it with the James Webb Telescope, scheduled to launch in 2018.
The Hubble Space Telescope's elevated perspective and advanced optics allow it to peer farther away than previous ground-based optics are able to see. Because light takes time to travel long distances, the range of the HST makes it function similar to a time machine; the light it views from remote objects only reveals how that object appeared when the light left it, not how it appears today. Thus when we look at the Andromeda galaxy, 2.5 million light-years from Earth, we see it as it was 2.5 million years ago.
And with Hubble, distant objects are revealed that otherwise can’t be seen at all.
When astronomers pointed the HST to a seemingly-empty patch of sky, for instance, they captured an image of over 3,000 galaxies too distant to be detected by other telescopes. Some of the galaxies were so young, they had not yet begun serious star formation. Other deep field observations have since been taken, providing a wealth of information.
In addition to gazing at the early universe, Hubble also helped astronomers gauge how much time had passed since the Big Bang. By measuring a special kind of pulsing star known as a Cepheid variable, they were able to narrow down the age of the universe from its pre-HST range of 10 to 20 billion years to a more precise 13.7 billion years.
In addition to galaxies, the Hubble Space Telescope also examines individual stars in various stages of their evolution – from the clouds of dust that form infant stars to the corpses of those long since detonated, and those in between. It has even been able to peer outside of our galaxy, the Milky Way, and into its neighbors, the Magellanic Clouds and Andromeda Galaxy.
More challenging to see than stars are planets orbiting other suns. Yet in 2008, Hubble captured pictures of the planet Fomalhaut b, the first time an extrasolar planet was directly imaged in visible light. But most planets are more challenging to photograph. Much of the HST's work with other planets comes through the detection of their atmosphere as they pass in front of their sun; the atmosphere filters the light from the stars, and the Hubble records the changes.
The Hubble Space Telescope may spend much of its time peering light-years from Earth, but on occasion it takes the time to photograph the planets traveling around our sun. High resolution images taken of Jupiter, Saturn, and even Pluto can provide insights that can only be topped by planetary probes circling the planets. Images from the HST allows scientists on Earth to monitor changes in the planet's atmosphere and surface. When the comet Shoemaker-Levy crashed into the Jupiter in 1994, the Hubble Space Telescope photographed the fatal collision. The aftermath revealed a great deal about the gas giant's atmosphere.
In orbit for more than two decades, the Hubble Space Telescope has provided scientists with a greater understanding of the planets, galaxy, and the whole universe. Among the Most Amazing Hubble Discoveries and research projects:
- Creating a 3-D map of mysterious dark matter.
- Discovering Nix and Hydra, two moons of Pluto.
- Helping determine the rate of the universe’s expansion.
- Discovering that nearly every major galaxy is anchored by a black hole.
- Helping refine the age of the universe.
Great Hubble Pictures
Below are some of the best images taken by the Hubble Space Telescope [See a gallery of awesome Hubble pictures]:
See links to more images below.
The Hubble Space Telescope is a joint project between NASA and the European Space Agency. Here are some basic facts about the telescope and the mission, courtesy the Space Telescope Science Institute (STScI), which operates Hubble for NASA:
- Length: 43.5 ft (13.2 m)
- Weight: 24,500 lb (11,110 kg)
- Maximum Diameter: 14 ft (4.2 m)
- Launch: April 24, 1990 from space shuttle Discovery (STS-31)
- Deployment: April 25, 1990
- Servicing Mission 1: December 1993
- Servicing Mission 2: February 1997
- Servicing Mission 3A: December 1999
- Servicing Mission 3B: February 2002
- Servicing Mission 4: May 2009
- Orbit: Average altitude of 307 nautical miles (569 km, or 353 miles), inclined 28.5 degrees to the equator.
- Time to Complete one orbit: 97 minutes
- Speed: 17,500 mph (28,000 kph)
Hubble transmits about 120 gigabytes of science data every week. That would be roughly 3,600 feet (1,097 meters) of books on a shelf. The collection of pictures and data is stored on magneto-optical disks.
- Energy Source: The Sun
- Mechanism: Two 25-foot solar panels
- Power usage: 2,800 watts
- Batteries: 6 nickel-hydrogen (NiH), with a storage capacity equal to 20 car batteries
- Primary Mirror Diameter: 94.5 in (2.4 m)
- Primary Mirror Weight: 1,825 lb (828 kg)
- Secondary Mirror Diameter: 12 in (0.3 m)
- Secondary Mirror Weight: 27.4 lb (12.3 kg)
—Nola Taylor Redd
Links to additional Hubble images:
Saturn's Rings in Ultraviolet – A new look at some of the most well-known rings in the solar system. Credit: NASA and E. Karkoschka (University of Arizona)
Hubble Ultra Deep Field – Staring at a patch of dark sky, the HST turned up over 10,000 early galaxies unseen from the surface of Earth.. Credit: NASA, ESA, R. Windhorst (Arizona State University) and H. Yan (Spitzer Science Center, Caltech)
When Galaxies Collide – Two colliding galaxies produced a long-tailed, ring-shaped galaxy. Credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)
A Moon of Uranus – The HST captures an eclipse as the moon, Ariel, passes in front of the sun. Credit: NASA, ESA, L. Sromovsky (University of Wisconsin, Madison), H. Hammel (Space Science Institute), and K. Rages (SETI)
Dust Storms on Mars – Hubble captures images of dust storms on the red planet at the polar caps. Credit: NASA, James Bell (Cornell Univ.), Michael Wolff (Space Science Inst.), and The Hubble Heritage Team (STScI/AURA)
Butterfly Emerges From Stellar Death – A dying star ejecting dust and gas has created a beautiful planetary nebula. Credit: NASA, ESA, and the Hubble SM4 ERO Team
Cosmic Pearls From Supersonic Shockwave – Shock waves unleashed from a 1987 supernova are now colliding with the dust and gas around the star, heating the ring and causing it to glow. Credit: NASA, P. Challis, R. Kirshner (Harvard-Smithsonian Center for Astrophysics) and B. Sugerman (STScI)
Galactic Gas Bubbles – A bubble of gas in the center of the galaxy NGC 3079 rises above the flattened disk. Credits: NASA, Gerald Cecil (University of North Carolina), Sylvain Veilleux (University of Maryland), Joss Bland-Hawthorn (Anglo- Australian Observatory), and Alex Filippenko (University of California at Berkeley).
Eta Carinae – The Dumbel Explosion – Dust and gas exploding on both sides of the star, Eta Carinae, are shown in remarkable detail. Structures only 10 billion miles across can be observed despite the stars great distance. Credit: Jon Morse (University of Colorado), and NASA
The Ring Nebulae – A dying star shucked off the dust and gas to create the most famous planetary nebulae. The HST revealed dark clumps of material embedded in the edges of the gas ring, while the dying star hides in the center. Credit: The Hubble Heritage Team (AURA/STScI/NASA)
Preparing for the Trip to Vesta – Images taken by the HST helped astronomers and engineers plan for NASA's Dawn Mission to the asteroid Vesta and the protoplanet Ceres. Credits for Vesta: NASA; ESA; L. McFadden and J.Y. Li (University of Maryland, College Park); M. Mutchler and Z. Levay (Space Telescope Science Institute, Baltimore); P. Thomas (Cornell University); J. Parker and E.F. Young (Southwest Research Institute); and C.T. Russell and B. Schmidt (University of California, Los Angeles). Credits for Ceres: NASA; ESA; J. Parker (Southwest Research Institute); P. Thomas (Cornell University); L. McFadden (University of Maryland, College Park); and M. Mutchler and Z. Levay (Space Telescope Science Institute)
A Stream of Sub-atomic Particles – Electrons and other sub-atomic particles stream from a black hole in the center of the galaxy M87. Credit: NASA and The Hubble Heritage Team (STScI/AURA)
Shoemaker-Levy Bruises Jupiter – When the comet Shoemaker-Levy bombarded Jupiter in 1994, it left its mark on the planet. Credit: Hubble Space Telescope Comet Team and NASA