In the beginning… it was a fiery ball of rock. It was clouded with carbon, at extreme temperatures. How did it change so much? How did the Earth become habitable? A new scientific theory gets closer to that mystery.
Rocks and sea
The theory refers to the early years of the Earth. It suggests that foreign rocks interacted with sea water. And thus prompted the existence of biological matter.
“This period is the most enigmatic epoch in Earth’s history. This is the most complete theory for our first 500 million years,” noted Jun Korenaga. He is a professor of Earth and planetary sciences at Yale.
Earth began with an atmosphere much like that of the planet Venus. Its skies were filled with carbon dioxide. Earth’s surface temperature would have exceeded 200 degrees Celsius. When did biological life form? How?
“Somehow, a massive amount of atmospheric carbon had to be removed. We made a theoretical model of the very primitive Earth from scratch,” explained lead author Yoshinori Miyazaki.
In the studythere are aspects of thermodynamics, fluid mechanics and atmospheric physics. The conclusion is that the early Earth was covered with rocks that do not exist on Earth today.
Creating hydrogen
“These rocks must have been enriched in a mineral called pyroxene. They probably had a dark greenish color. And they were extremely enriched in magnesium,” Miyazaki said. Magnesium-rich minerals react with carbon dioxide to produce carbonates. A key role in sequestering atmospheric carbon.
When the molten Earth began to solidify, its moist, hydrated mantle convulsed vigorously. This accelerated the process of extracting CO2 from the atmosphere.
The rate of sequestration of atmospheric carbon would have been 10 times faster than would be possible with a mantle of present-day rocks. “These early Earth rocks would readily react with seawater to generate a large hydrogen flux. This is essential for the creation of biomolecules. We think it explains how the Earth became habitable. And how life arose,” Korenaga concluded.
