Police confirm that a man has been detained at Gatwick Airport under the Prevention of Terrorism Act while on route to America. Earth was a snowball, say scientists New evidence has emerged that the Earth was once a huge snowball completely covered in ice. A debate is going on among scientists over whether the Earth ever really was completely iced over hundreds of millions ago. Some experts insist that Snowball Earth did exist, while others argue that life could not have survived such an episode.
Critics maintain that sea-level ice never extended into equatorial regions.
They believe the tropical glacial deposits were formed by ice flowing down from the top of mountains. According the snowball theory, it was global warming in reverse that caused the Earth to freeze over. The planet gradually cooled as the amount of carbon dioxide in its atmosphere decreased. As a result, large expanses of ice formed, which reflected the Sun's rays back into space and caused even more cooling. This process continued slowly until the oceans were frozen to about 30 degrees latitude - from the North Pole down to New Orleans, and from the South Pole up to the tip of South Africa.