For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...

Do you miss Pluto? In 2006, the International Astronomical Union voted this bantam world off the island. It was no longer a planet — a peer of Mars, Jupiter and the rest. From then on, Pluto was to be ...

In the continued search for the hypothetical ninth planet in our Solar System, Michael Brown, the CalTech astronomer who led the demotion of Pluto to a dwarf planet in 2006, has co-written a new study ...

The coast looks clear for a NASA spacecraft's historic Pluto flyby less than two weeks from now. The New Horizons probe has spotted no signs of rings or additional moons in the Pluto system, so the ...

After nine years and three-billion miles, the New Horizons space probe will complete its close flyby of Pluto Tuesday at 7:49 a.m. EDT. Google is waiting in anticipation with the rest of the world as ...

Could there be life in Pluto’s liquid water ocean? If so, the “habitable zones” around distant stars where astronomers look for signs of life must be dramatically larger than anyone thought. If life ...

A NASA spacecraft speeding toward Pluto is casting a wary eye on the dwarf planet system, looking for anything that could trip it up in the home stretch of its historic mission. NASA's New Horizons ...