NASA's MAVEN spacecraft - first spacecraft dedicated to exploring Mars' upper atmosphere - successfully entered orbit on September 21, 2014 at 10:24 p.m. EDT.

It's an unlikely object in an improbable place -- a monster black hole lurking inside one of the tiniest galaxies ever known.

Peak tornado activity typically occurs in the region from early May to early July. It has moved an average of seven days earlier over the past six decades.

Spinosaurus was the largest known predatory dinosaur to roam the Earth. Scientists now say that it was also the first truly semiaquatic dinosaur.

The startling results of a new survey include 17 previously unknown monuments and dozens of burial mounds surrounding Stonehenge.

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.