A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth ...

There are a couple of ways that scientists can date planets, so which planets formed first in our solar system?

Pluto was reclassified as a dwarf planet in 2006. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system ...

By Will Dunham WASHINGTON (Reuters) -Just as Earth orbits the sun, most planets discovered beyond our solar system orbit a ...

A recent study by Princeton University astronomers suggests the possible existence of a previously undetected planet in our ...

All of our solar system’s planets are lining up to parade through the night sky at once. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known as a ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

Astronomers have discovered seeds of rocky planets forming in the gas around the baby sunlike star providing *** peek into the start of our own solar system. The the thing that we've discovered is ...

Our solar system is a smashing success. A new study suggests that from its earliest period—even before the last of its nebular gas had been consumed—Earth's solar system and its planets looked more ...

When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...