Mars' Valles Marineris is nearly 10 times as long as the Grand Canyon and three times as deep, but nobody knows how it formed.
New research proposes that the first black holes came from clumps of gravitinos, exotic, hypothetical particles that managed to survive the first chaotic years of the Big Bang.
Space.com caught up with NASA Planetary Defense Officer Lindley Johnson to discuss recent events and what's on the planetary-defense agenda in the coming year.
Congress wants a report investigating the December collapse of the iconic radio telescope at Arecibo Observatory by late February.
Protecting and preserving the historic sites where the Apollo astronauts first landed on the moon is now not only a good idea, it is also the law.
The White House has laid out a plan for overhauling the federal government's planetary-protection rules, which work to prevent contamination between Earth and other potentially habitable worlds.
A team of physicists recently used a string-theory technique to reveal that we're on the cusp of detecting phase transitions in the early universe through their gravitational wave signature.
If you're feeling lonely, take solace in remembering that there are countless tiny living things floating tens of thousands of feet above your head.
What if there is more than one cosmological agent for dark energy? This mixture would have strange effects in our universe, making it potentially detectable with upcoming surveys.
A massive jet launched from our galaxy's supermassive black hole may have destroyed any red giant stars that wandered into its path, a new study suggests.
It's easy enough to say what a star is: one of those bright pointy things that twinkle in the night sky. But the actual definition of a star is as rich and colorful as the stars themselves.
If you look up in the southern sky you can see the “pointer” stars, pointing towards the Southern Cross.
If there are other intelligent civilizations in the Milky Way, they are probably much closer than we are to the galactic center, and fairly young.
The supermassive black hole hiding in the center of our galaxy is much closer to Earth, about 2,000 light-years closer, than scientists thought.
The big galaxy at the core of the cluster Abell 2261 should harbor a supermassive black hole that weighs as much as 3 billion to 100 billion suns. But astronomers can't find it.
A photographer filmed the "Great Conjunction" of Jupiter and Saturn as the heavenly bodies passed by Burj Khalifa, the world's tallest building.