Astronomers have a new theory on how former 'fireball' Earth became habitable

Categories: SCIENCE NEWS Technology

                    The research, published in Nature, has been conducted by Yale University and the California Institute of Technology (Caltech).The theory covers Earth’s earliest years and involves “weird” rocks that interacted with seawater in just the right way to nudge biological matter into existence.Most scientists believe that Earth began with an atmosphere much like that of the planet Venus. Its skies were filled with carbon dioxide, more than 100,000 times the current level of atmospheric carbon, and Earth’s surface temperature would have exceeded 400 degrees Fahrenheit.

                     Biological life would have been unable to form, much less survive, under such conditions, scientists agree."Somehow, a massive amount of atmospheric carbon had to be removed," says planetary scientist Yoshinori Miyazaki, who is now working at the California Institute of Technology.“These rocks would have been enriched in a mineral called pyroxene, and they likely had a dark greenish color,” Miyazaki said. “More importantly, they were extremely enriched in magnesium, with a concentration level seldom observed in present-day rocks.”

                     Miyazaki said magnesium-rich minerals react with carbon dioxide to produce carbonates, thereby playing a key role in sequestering atmospheric carbon.“As an added bonus, these ‘weird’ rocks on the early Earth would readily react with seawater to generate a large flux of hydrogen, which is widely believed to be essential for the creation of biomolecules,” Korenaga said.The Lost City hydrothermal field’s abiotic production of hydrogen and methane has made it a prime location for investigating the origin of life on Earth.“Our theory has the potential to address not just how Earth became habitable, but also why life emerged on it,” Korenaga added.