Antarctica developed a continental-scale ice sheet 34 million years ago while Earth was about 5°C warmer than today — helped by slow-moving mantle waves that had spent more than 100 million years lifting its interior high enough for permanent ice to survive.
Life on Earth may have begun twice. A Science Advances study found that bacteria and archaea inherited one ancient genetic code but independently evolved the machinery needed to become free-living cells — leading the researchers to describe it as “one origin of the genetic code, but two origins of life.