The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Does our Solar System have 9 planets or only 8? Astronomers have gone back and forth on that a lot, with Pluto now being classified as a dwarf planet. However, out beyond Neptune there could be ...

Filmmaker Adam Nemoy helps celebrate the 90th anniversary of Pluto's discovery this month at the 6th annual 'I Heart Pluto' ...

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.

Why is Pluto no longer a planet? Discover the real reason behind Pluto’s reclassification as a dwarf planet and the science that led to this change.

The building blocks of life could have been delivered to Ceres by one or more space rocks from the outer asteroid belt.

In August 2006, the International Astronomical Union made the controversial, but correct, decision to demote Pluto from its ...

Our solar system contains planets, dwarf planets, asteroids and comets — but only one world is known to harbor life. Scientists have long debated whether Earth is truly unique. Perhaps our planet just ...

While the composition of gas and dust in a molecular cloud is fairly uniform, everything changes once a star begins to form.

Scientists have been unable to determine whether the dwarf planet’s organics were produced by its own chemical processes or ...

Enaiposha orbits a red dwarf star 47 light years away from our own Earth, upending previous theories of how planets are formed and structured and giving scientists a tempting window into the ...

Gaia-4b is considered a super-Jupiter planet, a relatively cold gas giant, orbiting its star over 570 Earth-days. That star ...