The Mystery of Earths Early Thaw

Long ago, the Sun shone much dimmer, delivering only seventy percent of today's heat. Scientists are baffled because Earth should have been a giant ball of ice, yet liquid water and life thrived.

This puzzle is known as the Faint Young Sun paradox. If our planet were truly that cold, it would have been trapped in a deep freeze for eons. Instead, geological evidence proves that rivers and oceans flowed freely during that era. Experts believe powerful greenhouse gases likely trapped enough warmth to keep our young world habitable against the odds.