As temperatures drop, broad-leafed deciduous trees – think maples and oaks – withdraw the green chlorophyll from their leaves. Their leaves turn colors and fall. Evergreens solve the problem of winter in a different way.
What kicked off a rapid cooling on Earth 12,800 years ago? Some geologists believe a fragmented comet or asteroid collided with Earth and caused the change. Read more from a scientist whose fieldwork at a South Carolina lake adds to the growing pile of evidence.
New research suggests that the tiny human species – that survived until about 18,000 years ago, later than any human species other than our own – evolved its small size remarkably quickly while living on an isolated island.
The stars are accessible to everyone, but where can you get the most from the night sky? Here are 10 great dark-sky places – mostly in the U.S. but also in Australia, New Zealand and Chile – for skywatching and stargazing.
Air temperatures in the Arctic are increasing at least twice as fast as the global average. What worries climate scientists about the Arctic summer of 2019? And why does it matter for the rest of the world?