Jupiter is already the biggest planet by far in our solar system, but new research suggests it was somehow once even larger than it is now. Twice as large, in fact. To put that into context, those ...

Pluto hasn't been a planet for almost 20 years. In the early 2000s, scientists discovered several objects of a similar size to Pluto. So, during the summer of 2006, members of the International ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. Astronomers have found a distant celestial body — ...

On May 21, the International Astronomical Union’s Minor Planet Center announced the discovery of 2017 OF 201, which, because of its distance beyond Neptune, is classified as a trans-Neptunian object ...

Mercury has long baffled astronomers because it defies much of what we know about planet formation. A new space mission ...