If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

Galaxies speckle the heavens like stars in a stunning new photo of the deep and distant universe.

The surface of Mammoth Cave National Park encompasses about 80 square miles. No one knows how big the underside is. More than 365 miles of the five-level cave system have been mapped, and new ...

This spectrograph map, generated from data collected by NASA's New Horizons probe, depicts the relatively uniform brightness ...

Magnetars are among the rarest—and weirdest—denizens of the galactic zoo. They have powerful magnetic fields and may be the ...

The cloud, named Eos after the Greek goddess of dawn, had eluded researchers because it contains very little carbon monoxide ...

But the people who discover Isle Royale treat this isolated realm like no other park: Isle Royale visitors typically stay there 3.5 days, while the average visit to a national park is about 4 hours.

Two new research studies explore how a stellar nursery in the heart of the Milky Way is affected by the region’s strong ...