This post is part of Issue#15: Winter
‘It was essentially another world’ says a student of NASA Goddard Institute about Snowball Earth. As per the Snowball Earth hypothesis, the earth was covered by glacial ice from pole to pole more than 650 million years ago. Sheets of glaciers stretched from the poles to the equator, covering the Earth in a frozen skin. These features appeared at three different times in Earth’s history
- at 750 million years ago
- at 635 million years ago
- at 580 million years ago
How is the Ice Age different from Snowball Earth?
During normal ice ages, ice sheets go outward from the poles and then come back, while in a snowball event, instead of coming back, the glaciers creep farther south.
Temperatures on Snowball Earth are estimated to have reached minus 58 degrees Fahrenheit (minus 50 degrees Celsius). As the ice spread, more heat was reflected back into space rather than absorbed by the planet, dropping temperatures down in a runaway effect that sped the formation of ice.
Scientists still aren’t certain what caused temperatures to rise again, but volcanic activity is a strong suspect.
What caused the Snowball Earths?
The actual cause of Snowball Earth is not known but many theories have been proposed. One of the more accepted theories is that the Earth froze because of lowering of greenhouse gases, mainly CO2 (carbon dioxide) and CH4 (methane). This would have made the global climate colder, creating larger areas of ice and snow.
Life after Snowball
Life almost completely died during Snowball Earth before it began again. David Attenborough, the younger brother of director Richard Attenborough, is at his explanatory best in the below documentary as he explores the Origin of Life on Earth.
Did You Know?
Although methane gas is mostly made by living organisms, it is sometimes also created by volcanic activity. Therefore, the recently launched Mangalyaan has been fitted with highly sensitive methane sensors to decide if the gas is of biological or geological origin.
Question: Answer in Comments
Points at stake: +1
- Gone Nutty
- No Time for Nuts
- Surviving Sid
All of these are short films from what film franchise produced by Blue Sky studios?
But if the Earth has become a giant ice block three times, could it happen again during human existence? Oh, dear.