A giant meteorite first discovered in 2014 caused a tsunami larger than any known in history and boiled the planet's oceans, according to scientists.
Asteroid S2, 200 times larger than the one that wiped out the dinosaurs, collided with Earth 3 billion years ago, when our planet was still in its “infancy.”
Scientists visited the site of a meteorite impact in South Africa and removed chunks of rock to try to understand what happened.
The team found signs that the massive meteorite not only brought destruction to Earth, but helped the planet's nascent life thrive.
“Even after the Earth formed, we know that a lot of debris flew through space and crashed into the Earth,” says the study's lead author, Harvard University professor Nadja Draban.
“But now we're finding that life was very resilient in the face of these enormous impacts, and that it actually thrived.”
S2 is between 40 and 60 kilometers wide and between 50 and 200 times larger than the famous meteorite that caused the extinction of the dinosaurs 66 million years ago. The rock was about 10 kilometers wide, a little less than the height of Everest (8,849 meters).
3 billion years ago, the Earth was in its early stages of development. It was a predominantly aquatic world, with a few continents. Life was very simple: there were only single-celled microbes.
The impact site, in an area known as the Barberton Greenstone Belt, is one of the oldest places on Earth that still preserves meteorite remains.
Draban has already made the trip three times with his fellow scientists, first by car as far as possible into the mountain complex and then completing the rest of the trip on foot, with a backpack.
They travel with rangers equipped with machine guns to protect them from wild animals such as elephants and rhinos or poachers in the national park.
Scientists were looking for small spherical particles or small pieces of rock left by the impact. With the help of hammers, they collected hundreds of kilograms of rock, which were taken for laboratory analysis.
Drapan placed the pieces considered the most expensive in his suitcase.
“I usually get stopped by security, but I give them a hard time, talk about how wonderful science is, and they get bored and let me pass,” he says.
The team was able to map what happened when S2 violently hit Earth. The impact left a 500 kilometer crater and pulverized rocks that rose at enormous speeds, creating a cloud that enveloped the entire planet.
“Imagine a rain cloud, but instead of drops of water falling, it's drops of molten rock falling from the sky,” Draban says.
A tsunami would devastate the planet, destroying the ocean floor and flooding coastal areas.
Draban says the famous 2004 Indian Ocean tsunami would have been considered small in comparison.
All this energy would have produced enough heat to boil the oceans and cause evaporation. The air temperature would have increased by about 100ºC.
The sky is dusty. If this darkness blocks sunlight, simple life forms on land or in surface waters that rely on photosynthesis will become extinct.
The impact is similar to that observed with other large meteorites.
But Traban and his team found something surprising. Evidence from the rocks suggests that the violent impact exposed nutrients such as phosphorus and iron, which helped simple organisms grow.
“Life was not only resilient, but it recovered and thrived very quickly,” says the scientist.
“It's like brushing your teeth in the morning. It kills 99.9% of bacteria, but they come back at night, right?
The new findings suggest that the large impacts acted like “giant fertilizers”, spreading substances essential for life, such as phosphorus, to different parts of the planet.
The tsunami would have brought iron-rich water to the surface from the depths, giving the microbes additional energy.
According to Troban, the findings reinforce an increasingly popular thesis among scientists that life in early Earth was aided by a series of rock impacts.
“Life after the impact appears to have found more favorable conditions and allowed it to thrive.”
The findings are published in the scientific journal Proceedings of the National Academy of Sciences.
