What happened when a rock the size of London hit the earth?

A giant meteorite first discovered in 2014 caused the largest tsunami in human history and boiled the oceans, scientists have discovered.

A space rock 200 times bigger than the one that wiped out the dinosaurs slammed into Earth three billion years ago when our planet was in its infancy.

Carrying sledge hammers, scientists hiked to the impact site in South Africa to chisel out pieces of rock to understand the crash.

The team also found evidence that massive asteroid impacts didn’t just bring destruction to Earth — they helped early life flourish.

“We know that after the Earth first formed, there was a lot of debris flying around in space,” said lead author of the new research, Professor Nadja Traban from Harvard University.

“But now we’re finding that life was really resilient in the wake of some of these giant impacts, and it really blossomed and thrived,” he says.

Meteorite S2 was larger than the space rock we are familiar with. About 10 km wide or the height of Mount Everest that led to the extinction of the dinosaurs 66 million years ago.

But S2 is 40-60km wide and 50-200 times its mass.

It hit Earth when it was in its early years and was very different. It is a water world with a few continents sticking out of the ocean. Life is very simple – single-celled microorganisms.

The impact site in the East Barberton Greenbelt is one of the oldest places on Earth to contain the remains of a meteorite crash.

Professor Trapan traveled there three times with his colleagues, visiting as many remote mountains as possible, then backpacking the rest of the way.

Rangers accompanied them with machine guns to protect them from wild animals like elephants or rhinos or poachers in the national park.

They looked for spherule particles, or small pieces of rock, left behind by the impact. Using sledge hammers, they collected hundreds of kilograms of rock and transported it back to the labs for analysis.

Professor Draban had very expensive pieces in his luggage.

“I usually get stopped by security, but I give them a big presentation about how amazing science is, and then they get really bored and let me pass,” he says.

The team has now recreated what S2 did when the meteor rampaged through Earth. It was a 500km crater and pulverized rock was ejected at incredible speeds, creating a cloud that circled the globe.

“Imagine a rain cloud, but instead of water droplets coming down, it’s like molten rock droplets falling from the sky,” says Professor Trapan.

A massive tsunami would sweep across the globe, tearing up the ocean floor and flooding coastal areas.

The 2004 Indian Ocean Tsunami pales in comparison, says Professor Traban.

All that energy would have produced massive amounts of heat that would have boiled the oceans and vaporized water tens of thousands of meters up. This would have raised the air temperature to 100C.

The sky would have turned black, choked with dust and particles. Without sunlight penetrating the darkness, simple life would have died out on land or in shallow water that relied on photosynthesis.

These impacts are similar to what geologists have found in other large meteorite impacts and what is suspected to be S2.

But what Professor Traban and his team discovered next was surprising. Rock evidence shows that violent disturbances mix nutrients such as phosphorus and iron that feed simple organisms.

“Life was not only resilient, but actually recovered quickly and thrived,” he says.

“It’s like brushing your teeth in the morning. It kills 99.9% of the bacteria, but by evening they’re all back, right? she says.

The new findings suggest that large impacts are like a giant fertiliser, sending materials essential to life such as phosphorus around the world.

Planet-sweeping tsunamis would have brought iron-rich water from the depths to the surface, providing extra energy for early microbes.

The findings add to a growing view among scientists that early life was aided by a violent succession of rocks striking Earth in its early years, Professor Draban says.

“It seems that life after the impact actually encountered more favorable conditions that allowed it to flourish,” he explains.

The findings are published in the scientific journal PNAS.