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Earth Survived 2 Close Calls With Supernovas

At least two ancient supernovas scattered radioactive debris across Earth and lit up the sky for humanity's early ancestors.
Posted at 5:52 PM, Apr 06, 2016

Earth has survived several close calls with supernovas.

New research in Nature shows strong evidence that Earth was bombarded by debris from supernova explosions at least twice in the past 10 million years.

Both explosions were too far away to do much damage, but they might've had unknown effects.

The first one happened around the time the ancestors of humans and chimps went their separate ways. The second one, around the time the human side started making stone tools.

Those early human ancestors would've seen a new star appear in the sky as bright as a full moon.

The evidence for the encounters came in the form of radioactive iron dust. Supernovas create a cloud of it, and some landed on Earth.

It's not clear what effects zipping through a cloud of radioactive dust would have had on the planet, but the timing of the supernovas roughly lines up to a period of cooler climate.

This video includes clips from Stephanie Dloniak / CC BY ND 3.0 and Michael Schulreich and images from SLAC National Accelerator Laboratory / Greg StewartDidier Descouens / CC BY SA 4.0 and Ian Norman / CC BY SA 2.0 and images and clips from NASA.