Mission scientists have found Pluto to be 1,473 miles (2,370 kilometers) in diameter, somewhat larger than many prior estimates. Images acquired with the Long Range Reconnaissance Imager (LORRI) were ...

On the eve of NASA's historic flyby of Pluto, scientists announced Monday that the New Horizons spacecraft has nailed the size of the faraway icy world. Measurements by the spacecraft set to sweep ...

For the most part, our moon is nothing particularly special. It isn’t home to a series of active volcanoes, a thick atmosphere chalked full of nitrogen (with oceans of liquid hydrocarbons), or ...

Update, July 13, 3015 at 20:00 UTC: Emily Lakdawalla has also written about this on her blog, with more details. Update 2, July 13, 2015 at 20:30 UTC: There has been some confusion about the ...

The Hubble Space Telescope may be getting old, but it still has excellent spotting power — witness its discovery of a fourth moon of Pluto, which is between 8 miles and 21 miles in diameter. Says ...

JUDY WOODRUFF: After a three-billion-mile journey by a spacecraft named New Horizons, NASA finally had the chance today to release the first ever close-up photos of the dwarf planet Pluto. The images ...