For many people, the definition of a planet was only made clear in 2006, when the spunky world Pluto was demoted from a planet to a dwarf planet. Now, a team of astronomers is pushing for “planet” ...

Add Yahoo as a preferred source to see more of our stories on Google. When you buy through links on our articles, Future and its syndication partners may earn a commission. In 2006, the International ...

The official definition of a “planet” could be set to change again soon. Last time that happened, Pluto was kicked out of the club, but the new proposed definition is designed to be more inclusive.

Will Pluto have the last laugh? A group of NASA scientists hopes so. A group of members of the New Horizons mission to Pluto are making the case to redefine what constitutes as a planet to be more ...

The world’s astronomers, under the auspices of the International Astronomical Union (IAU), have concluded two years of work defining the difference between “planets” and the smaller “solar system ...