A small team led by Sihao Cheng, Martin A. and Helen Chooljian Member in the Institute for Advanced Study's School of Natural ...

T he Solar System has just gotten a new official member. Currently, with the name of 2017 OF 201, this is a trans-Neptunian ...

There’s a new frozen oddball orbiting the Sun, and it’s not your average space rock. It’s a planet—a minor one, to be ...

One Pluto year equals 248 Earth years. At 1473 miles in diameter—about half the width of the United States—Pluto is the ...

Elon Musk, under the username "Kekius Maximus," has joined William Shatner in advocating for Pluto's reclassification as a ...

Stars that pass close to the solar system could pull planets out of alignment, sending them hurtling into the sun or out into ...

Billions of years ago, in the frozen edges of the solar system, a violent impact shaped one of space’s oddest pairs. Instead of a typical planet-moon setup, Pluto and Charon became a binary system.

The unusual orbit of a possible dwarf planet, known as 2017 OF201, makes it less likely that our solar system contains a ...

It must orbit the Sun. It must have sufficient mass for its gravity to shape it into a nearly round form. It must have cleared its orbital path of other debris. Pluto fails the third criterion as ...

But then scientists at the International Astronomical Union decided Pluto didn’t quite make the cut, it lacked the gravitational muscle to clear its orbit. Ouch. Now officially labeled a ...

The International Astronomical Union, which reclassified Pluto as a dwarf planet in 2006, is the arbiter of such ...

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...