Pluto

Scientists have spent 12 years arguing over how to classify Pluto, and a recently published paper offers a new — but surprisingly old — reason for restoring the object's planetary status.

"Ask a Spaceman" is live for the first time on Facebook — and astrophysicist Paul Sutter jumps right into it with a trip to Pluto.

Forty years ago, Pluto's largest moon Charon was discovered.

Scientists have put together new maps of Pluto and its moon Charon, showing the peaks and valleys of their surfaces in incredible detail.

Pluto has an extensive dune system, but the grains that make up the wind-blown mounds are certainly not sand, a new study reports.

Pluto may have long ago coalesced from 1 billion or so comets, a new analysis of data from NASA's New Horizons mission and the European comet-orbiting Rosetta probe suggests.

The long-simmering argument about Pluto's planethood has just flared up again.

The names of explorers and the authors of journeys make up some of the first feature names for Charon.

A thick, gooey, asphalt-like layer could lie beneath Pluto's crust.