Washington: NASA's New Horizons probe has settled one of the most basic questions about Pluto - its size. Mission scientists have found Pluto to be 2,370 kms in diameter, somewhat larger than many ...

Pluto will complete its first orbit since 1930 in 2178, a historic 248-year space journey that spans generations of humans.

Editor’s note: A version of this story originally appeared in Astronomy’s 2007 special issue 50 Greatest Mysteries of the Universe. For a more recent discussion of Pluto’s planethood, see “An ...

A new study provides the best estimate to date of the diameter and heft of Pluto’s moon Charon and suggests that the satellite likely has no atmosphere. Charon is the largest known moon in relation to ...