Did Bolide Bombardment Kill Life on Earth More Than Once? – #365papers – 2018 – 36

Grimm and Marchi, 2018, Direct thermal effects of the Hadean bombardment did not limit early subsurface habitability: Earth and Planetary Science Letters, v. 485, p. 1-8.

What’s it about?

The first billion years or so of Earth’s existence was marked by repeated bombardment of the planet by various asteroids, and even planetessimals. It is thought that this bombardment would superheat the Earth’s surface and kill any life that may have started to develop there. This study shows that, while the heating was extreme, there were still places that were protected from life-killing heat.

Why does it matter?

A major question in science is the timing of the origin of life on the planet. If bombardment sterilized the planet, then life could not have originated until after 3.5 billion years ago. But, by the interpretation of these authors, life may have originated much earlier.

Why did I read this?

Like many paleobiologists, I am interested in the origins of life. This paper places an older limit on the possible development of life on Earth.

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