Ongoing drought - and increasing temperatures - have reduced water flow in the Colorado River, with more dramatic reductions expected. This ongoing, unprecedented event threatens water supplies in cities in the U.S. West and some of the most productive agricultural lands anywhere in the world.

Featured in National Geographic and Nature, Canadian amateur astronomer Christian Sasse explains how he created his unique star trails, by superimposing images.

Albert Einstein hypothesized these ripples in the fabric of space-time a century ago. Now scientists have detected them for the 3rd time, from distant black hole collisions.

More tornadoes occur in the U.S. than any other country, mainly in the Great Plains, Midwest and southern states. Two meteorology professors answer questions.

When astronomers aimed the Very Large Array at the well-studied galaxy Cygnus A, they were surprised to find a bright new object near the galaxy’s core. Supernova explosion, or a second supermassive black hole?

Happening now in Denmark: "bright nights," when the sun is never far below the horizon. Photographer and videographer Adrien Mauduit tells the story and provides stunning imagery.

New data on the massive molten lake on Jupiter's moon Io - most volcanically active world in our solar system - suggest 2 lava waves per day, slowly sweeping west to east.

We can't observe brain activity of extinct human species. But we can observe modern brains doing things that our distant ancestors did for clues to how their brains worked.

This article from NASA's Center for Near-Earth Object Studies provides fresh details on the closest approach by a large asteroid since 2004 ... and shows you how science works.

Twitter has been blowing up with posts on cats' attraction to taped squares on the ground. An animal behavior expert explains what draws Fluffy to the #CatSquare.