The Montreal Protocol put the brakes on ozone-depleting chemicals 30 years ago. But one compound is still abundant in Earth’s atmosphere. Where's it coming from?

Asteroid passes near Earth on September 7. At its closest (18:18 UTC / 2:18 p.m. EDT), it's about the same distance from Earth as weather and communications satellites.

Astronomers have learned that our Local Group of galaxies - known to be part of the Virgo Supercluster - is also part of an even-larger supercluster. The newly identified supercluster is called Laniakea, which is Hawaiian for "immense heaven."

With ongoing climate change, the long view of future drought risk in the U.S. Southwest is not a pretty picture, say scientists.

An MIT study finds big snowstorms will still occur in the Northern Hemisphere despite global warming.

A NASA sounding rocket has confirmed that the solar system is inside an ancient supernova remnant. Life on Earth survived despite the nearby blasts.

Using telescopes on the ground and in space, astronomers have obtained the best-yet view of a galaxy collision that happened when the universe was half its current age.

Next time you're brushing you teeth, think on this: New research suggests that the fluorine in your toothpaste originates from the sun’s dead ancestors.

New image of star-forming regions in southern Milky Way. Star cluster NGC 3603 is 20,000 light-years away. Glowing gas clouds NGC 3576 is about half as far.

This strange fossil - a worm-like creature with legs, spikes and a head that's difficult to distinguish from its tail – has been linked with a group of modern velvet worms.