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 ...
President Donald Trump and his NASA administrator are reviving the Pluto debate again — apparently at the urging of “Star ...
Until 2015, Pluto, the former ninth planet of the classical solar system, was largely a mystery—a tiny speck 3.6 billion miles from the sun. When NASA's New Horizons spacecraft arrived at the ...
Add Yahoo as a preferred source to see more of our stories on Google. A huge heart-shaped feature on the surface of Pluto has intrigued astronomers since NASA’s New Horizons spacecraft captured it in ...