Photos and videos of astronauts on the ISS show them floating around, but saying there's zero gravity isn't fully accurate.

Shedding light on the gravity of the situation. Most people do not realize that many of the stars and heavenly bodies they see in the sky no longer exist. In fact, many have ceased to exist for ...

More than a 150 years ago, before Neptune was ever sighted in the night sky, French mathematician Urbain Le Verrier predicted the planet’s existence based on small deviations in the motion of Uranus.

Does dark matter follow the same laws as ordinary matter? The mystery of this invisible and hypothetical component of our ...

How do you explore the interior of a planet without ever touching down on it? Start by watching the way the planet spins, then measure how your spacecraft orbits it — very, very carefully. This is ...

Rogue planets do not orbit around a star, but instead wander through the galaxy aimlessly. NASA estimates there are billions ...

Scientists have discovered that dark matter, the universe's most mysterious "stuff," obeys gravity on vast cosmological scales. This could help to dismiss the possibility of a fifth fundamental force ...

In about 5 billion years, our Sun will run out of hydrogen fuel and collapse into a dense, Earth-sized remnant called a white dwarf. Though it will no longer shine as it once did, this stellar core ...