A giant, ancient meteorite may have helped life on Earth thrive

Hannah Peart

Updated Wed, October 23, 2024 at 5:55 AM GMT+7·3 min read

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It was four times the size of Mount Everest, unleashed a tsunami bigger than any in known human history and boiled the oceans — but an ancient meteor may also have nurtured life on Earth after smashing into it, scientists have discovered.

The meteorite, S2, was discovered in 2014. It hit the planet about 3.26 billion years ago and is estimated to have been up to 200 times larger than the space rock that later killed the dinosaurs.

The new findings, published in the scientific journal Proceedings of the National Academy of Sciences on Monday, suggest that this massive collision not only brought destruction to Earth, but also helped early life thrive.

“We know that giant meteorite impacts were frequent during Earth’s infancy and that they must have affected the evolution of early life, but we didn’t have a good understanding of how,” Harvard University geologist Nadja Drabon, lead author of the study, told NBC News in an email.

The research has been a passion project for Drabon, who was inspired by numerous previous studies that showed the potential impact a meteorite collision can have on life forms.

“We have long known that on the young Earth meteorite impacts were both more frequent and, on average, larger than today,” said Andrew Knoll, a Harvard geologist and study co-author.

“While people have speculated about the potential biological and environmental consequences of ancient impacts, there has been little hard data to test varying hypotheses,” Knoll added.

The research team traveled for three field seasons to Barberton Greenstone Belt in South Africa to collect the samples needed for the study, accompanied with years of laboratory work, Drabon said.

The meteorite struck Earth when it was still in its early years, a water world with only a few continents sticking out of the sea.

In their fieldwork, Drabon said, they were looking for spherule particles or tiny fragments of rock left behind by the impact of the meteorite.

The team collected 220 pounds of rock and took them back to the lab for analysis.

The giant meteorite caused a tsunami to sweep across the planet, the scientists found. Heat from the impact caused the topmost layer of the ocean to boil off, while also heating the atmosphere.

They found rock evidence showing that the tsunami churned up nutrients such as iron and phosphorus.

Additionally, there was partial ocean evaporation, and darkness that likely harmed shallow-water photosynthetic microbes in the short term.

Life in the deeper oceans was less affected, the scientists found.

Jon Wade, associate professor of planetary materials at Oxford University in England, said the distribution of this iron-rich water is the crucial element to how life began.

Iron is the most abundant element by mass in the Earth, but most of it is locked up in the Earth’s core, 1,800 miles beneath our feet, Wade said.

Despite this, life forms rely on iron for survival. Only two life forms — lactobacilli, found in yogurt, and Borrelia burgdorferi, which is responsible for Lyme disease — are currently not dependent on iron.

As a result, there was a temporary boom of microorganisms that relied on iron.

The study has drawn global media coverage, something the team said they were not anticipating.

“There has been a surprising amount of interest in the paper; I suppose we have the dinosaurs to thank for that,” Knoll said.

“I get very excited about my research and I know that the results are important to the scientific community,” Drabon said. “Seeing that the public is interested as well has been a very welcome surprise.”