“We found evidence that may indicate a change in the structure of iron, which suggests perhaps two separate cooling events in Earth’s history,” said Joanne Stephenson, a researcher from The Australian National University (ANU), about the confirmation of the existence of the Earth’s “innermost inner core” that may point to an unknown, dramatic event in the Earth’s history.
“Early Mars was an extremely active planet from a geological point of view,” said Alberto G. Fairén, a visiting astrobiologist at Cornell University. “The planet had the conditions needed to support the presence of liquid water on the surface – and on Earth, where there’s water, there’s life. “So early Mars was a habitable planet,” he said. “Was it inhabited? That’s a question that the next rover Perseverance will help to answer.”
“So they’re kind of like dark matter,” said paleontologist David Jablonski of the University of Chicago about the sanctuaries, the “refugia” that have never been found in the fossil record, but sheltered the shell-shocked and decimated species of Earth’s past mass extinctions until they were able to repopulate the planet in ensuing eons.
“Currently, Earth is the only known planetary body that has robustly established plate tectonics of any kind,” said Alec Brenner, a member Harvard’s Paleomagnetics Lab about the tectonic plates that began pushing and pulling in a process that helped the planet evolve and shaped its continents into the ones that exist today as early as four billion years ago.
Earth’s tectonic activity of some 15 moving plates may be crucial for life–and rare in our galaxy. The cycle of rigid tectonic plates in constant horizontal motion across the surface of the planet—makes Earth unique within the rocky planets of the solar system. Except, perhaps, for Jupiter’s icy moon Europa, regarded as perhaps one of the solar system’s best bets to host alien life, where massive slabs of ice are sliding over and under each other above a global ocean that reaches down 100 kilometers below the base of the ice –a depth 10 times greater than the Marianas Trench.
“It is remarkable to think that our oldest animal ancestors—and therefore all of us—may owe our existence, in part, to an unusual episode of plate tectonics over half a billion years ago” said Tim Lenton, professor of Climate Change and Earth System Science with the University of Exeter’s Global Systems Institute in June, 2019 about the most dramatic moment in the history of evolution when the spectacular supernova of biology, the Cambrian Explosion, was detonated and the world of animal life was born with the rise in oxygen levels during the formation of the supercontinent Gondwana and a major increase in continental arc volcanism—chains of volcanoes often thousands of miles long formed where continental and oceanic tectonic plates collided.