Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously ...

Far beyond Neptune, something heavy appears to be tugging on the outer solar system, bending the paths of distant icy worlds ...

The newly identified cluster of Kuiper Belt objects lies about 4 billion miles from the Sun, offering fresh clues about how ...

In the cold, distant reaches of the Solar System, far beyond Pluto, astronomers have just identified what could be a new dwarf planet. It's called 2017 OF 201, a rock that appears to be some 700 ...

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

This is a montage of Hubble Space Telescope views of our solar system's four giant outer planets: Jupiter, Saturn, Uranus, and Neptune, each shown in enhanced color. The images were taken over nearly ...

In the remote outer reaches of planetary systems, far beyond the orbit of known planets, enormous and mysterious worlds silently loop around their stars. Some drift as far as 10,000 times the distance ...

When 'Oumuamua traversed our solar system in 2017 it was the first confirmed Interstellar Object (ISO) to do so. Then in 2019, Comet 2l/Borisov did the same thing. These are the only two confirmed ...

The Sun's formation caused temperature differences in the surrounding disk of gas and dust. Inner, hotter regions formed rocky planets from less volatile elements. Outer, colder regions allowed ...