Discovered in 1930 at the Lowell Observatory, Pluto was demoted as a planet in 2006. Some want President Trump to take action ...

President Donald Trump and his NASA administrator are reviving the Pluto debate again — apparently at the urging of “Star ...

Debate has raged for two decades over whether Pluto should be considered a planet. Some want President Trump to take action via executive order.

The International Astronomical Union declared that Pluto only fulfills two of the three criteria for a full-size planet. Pluto, discovered 90 years ago on Feb. 18, 1930, was long considered the solar ...

Add Yahoo as a preferred source to see more of our stories on Google. NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto on July 14, 2015. The image combines ...

February 18 marks the discovery of Pluto by astronomer Clyde W. Tombaugh. The discovery reshaped the understanding of the solar system, as Pluto was long considered the ninth planet until the ...

The renewed push is stirring controversy nearly two decades after the dwarf planet classification was introduced. Renewed debate NASA chief Jared Isaacman has voiced support for reclassifying Pluto as ...

Arizona has a new state emblem — and it's one that has been a source of controversy among scientists for years. Gov. Katie Hobbs signed a bill on Friday designating Pluto — once considered the ninth ...