Some 700 million years ago, #Earth would have looked like a blinding white #snowball.
During the #Cryogenian period, from 720 million to 635 million years ago, the Earth was buried by massive ice sheets that marched from the poles to the tropics.
Surface temperatures were as low as -50°C.
Because the bright, white surface of the #planet reflected the Sun’s energy – a phenomenon known as the albedo effect – the Earth remained locked in this extreme climate state for tens of millions of years.
This seems an unlikely cradle for #life, yet new evidence suggests the frozen #ocean featured restricted ice-free oases that provided a lifeline for our earliest complex ancestors.
#astrobiology #planets
https://theconversation.com/snowball-earth-wasnt-fully-frozen-ice-free-oases-sheltered-early-life-275240
