After a decade-long search, some scientists say a growing number of clues point to the existence of a hidden planet in the Kuiper Belt beyond Neptune — and they may soon have the opportunity to find ...

The solar system has nine planets, but in 2006 the International Astronomical Union declared Pluto a dwarf planet, making the ...

With 8 planets now known, the thoughts of astronomers ... than any of the planets in the outer solar system. Nevertheless, because it orbited the Sun like a planet, it was classified as a planet ...

Exoplanets can be quite different from Earth, but occasionally researchers find one that gives a sneak peak into what the ...

The Subaru Telescope has discovered new objects beyond the known Kuiper Belt, suggesting a more complex structure at the edge ...