On Aug. 24, 2006, the International Astronomical Union voted to strictly define a planet, which ultimately downgraded Pluto from the ninth planet from the sun to a dwarf planet — causing controversy ...

Pluto's days, though they drag on a bit at around 153 hours, are nothing compared to its years. Pluto's orbit takes 248 Earth ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

The James Webb Space Telescope (JWST) has discovered that a hazy sky over frozen Pluto is helping to cool the dwarf planet's atmosphere, while at the same time giving methane and other organic ...