Found in the northern sky, GJ 3378b is a potentially rocky world with liquid water on its surface, receiving 90% of the ...

“This isn’t what we expected at all,” researchers said of a Mega-Earth that defies planet formation theories.

"This isn't what we expected at all." ...

It's nearly 170 million years old. It's more than 2.5 times the size of Earth. And it's the first exoplanet discovered and ...

Scientists have found a massive rocky world far beyond our solar system that is more than 20 times the mass of Earth.

The object orbits a brown dwarf that orbits a star, and astronomers aren’t sure if it’s a planet, a moon — or something else entirely.

Earth,” your mind probably jumps straight to a sci-fi blockbuster movie poster or a comic book alternate dimension. But ...

Discovered in 1930, Pluto reigned as the ninth planet for 76 years — now, 20 years after its demotion, the debate still rages ...

The four astronauts who rounded Earth’s natural satellite in April got an extremely rare view of the dark lunar disk blocking ...