Brewing Life On Earth - Violent Sun, Weak Shielding May Have Contributed | Video

4 billion years ago, the Sun was cooler than it was today, but much more active. Earth's weaker magnetosphere allowed particles from solar flares to seep into the atmosphere, contributing to the creation of the greenhouse gas nitrous oxide. This is turn would have made it warm enough to 'brew and incubate life on Earth,' according to NASA.
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Credit: NASA/GSFC