Frigid and far-flung Neptune, our solar system's outermost planet, is adding to its reputation as an enigmatic world, with astronomers puzzled by a surprising drop in its atmospheric temperatures ...

Neptune has long been pictured as a deep, rich blue. Researchers reprocessed NASA images to show its true hue.

Neptune, planet of dreams, drugs, vision, and oblivion, is going retrograde this summer.

A Neptune-like planet has never been found so close to its host star. And in fact, astronomers came up with a term, the “Neptune desert,” to describe this up-close-and-personal stellar zone.

Scientists recently discovered water vapor in the atmosphere of a recently discovered planet, NASA announced Thursday.