More than 2 billion years ago, a much fainter sun should have left the Earth as an orbiting ice ball. Why we avoided the deep freeze is a question that has puzzled scientists, but one astronomer might have an answer.
More than 2 billion years ago, a much fainter sun should have left the Earth as an orbiting ice ball. Why we avoided the deep freeze is a question that has puzzled scientists, but one astronomer might have an answer.