Mammal body size decreased significantly during at least two ancient global warming events. A new finding suggests a similar outcome is possible in response to human-caused climate change.

Satellite image showing shadow over Africa about 38 minutes after the maximum eclipse on November 3, 2013.

Two knee surgeons at University Hospitals Leuven have discovered a previously undescribed ligament in the human knee. The ligament appears to play an important role in patients with anterior cruciate ligament (ACL) tears.

"What this means is, when you look up at the thousands of stars in the night sky, the nearest sun-like star with an Earth-size planet in its habitable zone is probably only 12 light years away and can be seen with the naked eye." - Erik Petigura

The increased sea temperature expected in 2100 will in itself mean that the potential number of species introduced by ships will increase more than sixfold in the Norwegian Archipelago Svalbard in the Arctic Ocean.

Find out what deep space sounds like in a new video from NASA.

Warming western temperatures may mean that some of the creeks and streams that Salt Lake City relies on will dry up several weeks earlier in the summer and fall.

Technological approaches to reduce future global warming could also interfere with rainfall and snowfall.

The ozone hole over the South Pole on September 16, 2013. The ozone hole was slightly smaller in 2013 than the average for recent decades.

With a radius about 1.2 times that of Earth and a mass equal to about 1.7 times Earth’s, Kepler-78b has a density that's the same as Earth’s, suggesting that it is also made primarily of rock and iron.