Australian researchers have provided compelling evidence to support the frozen Earth theory. The entire planet was covered in ice extending from the poles to the equator about 700 million years ago, with very low temperatures.
Traces of this ice dating back to the Cryogenian period, specifically to the Sturtian era, when the Earth was like a huge snowball traveling in space. Scientists expect that similar ice ages may occur again, especially if current climate changes lead to significant melting of the Greenland ice sheet.