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.

Researchers have uncovered 300,000 year-old fossil bones of Homo sapiens in Morocco, the oldest reliably-dated fossil evidence of our species yet.

Words often fail when trying to explain the kaleidoscope of sights, sounds, feelings and emotions that consume us during this other-worldly event.

Awesome observation! Astronomers used the Hubble Space Telescope to measure the mass of a nearby white dwarf, as it bent the light of a more distant star.

On June 3, July 10 and July 17, astronomers will be watching as tiny MU69 in the outer solar system - the New Horizons spacecraft's next target - occults or blocks the light from 3 different stars.

New video from NASA about studies looking at the effects of space travel on the human body's immune system.

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.

Super cool, interactive image of a transit across the sky of the International Space Station, via Project Nightflight of Austria.

Radar astronomers are peering toward asteroid 2017 CS, closest on May 29. Another asteroid - 418094 (2007 WV4) - will be closest June 1. Charts here for Saturday night, for 8-inch or larger 'scopes!

Our teeth evolved from the same genes that make the bizarre beaked teeth of the pufferfish, according to new research.