Planetary scientists are proposing a new definition of a planet to replace one that many researchers view as sun-centric and outdated. The current definition—established in 2006 by the International ...

Planets sort of look like big basketballs in space, floating around aimlessly. Sometimes they have rings. Other times, they look like gnocchi. More or less, to the average stargazer, planets have ...

Officially, Pluto is still not a planet. But five years after the ruling that demoted the icy object to dwarf planet, people continue struggling with the definition, and the debate over what exactly ...

While thousands of planets have been discovered around other stars, relatively little is known about them. A NASA catalog featuring 126 exotic, newly discovered worlds includes detailed measurements ...