How many dwarf planets are there in our solar system? The recent discovery of 2017 OF201 makes the tally anywhere between ...

The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy ... Objects need to be at least 400 km or so in size to round out via self-gravity, ...

A theory developed to replace dark matter may mean bad news for Planet Nine, a hypothetical as-yet-unseen world in the outer solar system.The odd orbital alignments of icy objects in this region ...

Rogue planets that range from Mars mass to Earth mass will be future targets for the Roman telescope. As they cross in front of a star and bend spacetime (therefore bending the star’s light ...

"We estimate that our galaxy is home to 20 times more rogue planets than stars – trillions of worlds wandering alone," David Bannett, co-author of both studies and an astronomer at NASA's ...

NASA scientists have discovered an electric field encompassing Earth’s atmosphere that is as "fundamental" as gravity -- and could even give clues about possible life on other planets.

Gas planets are not the only example of celestial bodies that resist diffusion due to gravity. Like gas planets, “stars are just giant balls of gas,” said Knittle. “And they hold together.” ...

One common question people seem to have about the planets' orbits is why the planets are drifting away from the Sun, given the Sun's strong gravitational pull keeping the Solar System together ...