At 13.8 billion years ago, our entire observable universe was the size of a peach and had a temperature of over a trillion degrees.
Stars are giant, luminous spheres of plasma. Galaxies consist of stars, stellar remnants, dust, gas, and dark matter, bound together by gravity. Learn more about stars and galaxies.
Like a ship cruising the seas or a fighter jet going supersonic, astronomic objects also make shock waves through the medium in which they travel.
NASA's next exoplanet-hunting spacecraft, the Transiting Exoplanet Survey Satellite, will take to the skies one week from today (April 9), if all goes according to plan.
Our Milky Way galaxy is growing faster than the speed of sound as new stars pop up in its hinterlands, a new study suggests.
In this cloudy, winter scene, a bright and fast meteor crosses the night sky near Arcturus, the brightest star in the constellation Boötes.
Two galaxies surrounding our Milky Way are playing a game of gravitational tug-of-war, and new data from NASA's Hubble Space Telescope has revealed the cosmic winner.
Using data from NASA's Kepler space telescope, astronomers detected the rapid evolution and violent explosion of a dying star cocooned inside a dense shell of gas and dust.
The U.S. National Park Service has partnered with the McDonald Observatory to create training programs for park rangers and improve skywatching events.
Some distant objects in our solar system bear the gravitational imprint of a small star's close flyby 70,000 years ago, a new study suggests.
The Hubble Space Telescope has snapped views of 93 deep-sky objects from French astronomer Charles Messier's famous list. Here are some of the most spectacular.
The European Space Agency has selected the Atmospheric Remote‐sensing Infrared Exoplanet Large‐survey (ARIEL) project as its next medium-class space mission, with a launch targeted for 2028.
With the impending arrival of spring, we can step out during the late evening hours (around 11 p.m. local daylight time) and count up to 11 "first-magnitude" stars – the brightest in the sky.
Amateur astronomers had 12 spectacular new images to look to during this year's Messier marathon, a skywatching challenge that happened on the weekend of March 17 and 18.
Astronomers say there are 100 billion to 200 billion galaxies in the universe. But accurately counting the number of galaxies depends on several factors.
Our solar system's first known interstellar visitor is likely even more alien than previously imagined, a new study suggests.
Albert Einstein's vision for how gravity works was, to say the least, a radical departure from the older, Newtonian perspective.