On Aug. 24, 2006, the International Astronomical Union (IAU) decided that Pluto wasn't a planet anymore. Instead, Pluto is ...

The solar system has many more moons than the one we can see in the sky. But how many do we actually know about? And how many ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

Astronomers have identified a strikingly large gas giant orbiting a remarkably small red dwarf star — a finding that ...

On August 24, 2006, Pluto ceased to be considered a planet. A mixture of rock and ice located in the Kuiper Belt, a region of icy objects beyond the orbit of Neptune. This demotion ...

The Solar System does not have a clear border. The influence of the Sun in certain domains is small enough for the Voyager ...

Pluto, the largest of those dwarf planets, has a diameter of about 1,477 miles. Don't miss out on what's happening! Stay in touch with breaking news, as it happens, conveniently in your email inbox.

For the first time, a planet has been discovered orbiting a white dwarf, also known as a dead star. This exoplanet, a planet outside of our solar system, is the size of Jupiter and it's known as ...

Astronomers discover GJ 2126 b, a giant planet with an extremely eccentric orbit, 124 light-years away, using HARPS data.

Astronomers have discovered a rare quadruple star system with two red dwarfs and two brown dwarfs orbiting together.

A newly discovered dwarf planet has grabbed the crown as the most distant known object in our solar system – and its orbit hints at a giant, unseen rocky world, 10 times the mass of Earth and ...