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

Scientists have discovered that a massive meteorite first discovered in 2014 caused a tsunami larger than any known in human history and boiled the oceans.

The space rock, which was 200 times larger than the one that wiped out the dinosaurs, collided with Earth when our planet was in its infancy three billion years ago.

Scientists, carrying heavy hammers, went to the impact site in South Africa to cut off pieces of rock to understand the accident.

The team also found evidence that massive asteroid impacts not only brought devastation to Earth, but helped early life flourish.

“We know that after the Earth first formed, there was still a lot of debris flying around space that would have collided with the Earth,” says Professor Nadia Drabon from Harvard University, lead author of the new research.

“But now we're discovering that life was really resilient in the wake of some of these giant impacts, and that it actually thrived and thrived,” she says.

The S2 meteorite was much larger than the space rock we are most familiar with. The one that led to the extinction of the dinosaurs 66 million years ago was about 10 kilometers wide, or roughly the height of Mount Everest.

But S2 was 40 to 60 kilometers across and 50 to 200 times more massive.

It struck when the Earth was still in its early years and looked completely different. It was a water world with only a few continents sticking out of the sea. Life was very simple – tiny organisms made up of single cells.

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

Professor Drabon traveled there three times with colleagues, driving as far into the remote mountains as she could before walking the rest of the way with backpacks.

Rangers accompanied them with automatic rifles to protect them from wild animals such as elephants or rhinos, or even poachers in the national park.

They were looking for spherical particles, or small fragments of rock, left behind by impacts. Using sledgehammers, they collected hundreds of kilograms of rocks and brought them back to laboratories for analysis.

Professor Drapon stored the most expensive pieces in her bags.

“I usually get stopped by security, but I give them a rant about how exciting science is, and then they get really bored and let me pass,” she says.

The team has now reconstructed what meteorite S2 did as it careened violently toward Earth. It created a crater 500 kilometers deep and crushed rocks that were ejected at incredibly high speeds to form a cloud that circled the globe.

“Imagine a rain cloud, but instead of water droplets falling, it looks like droplets of molten rock raining down from the sky,” Professor Drabon says.

A huge tsunami would have swept across the world, tearing up the seafloor and submerging coastlines.

Professor Drabon points out that the 2004 Indian Ocean tsunami would have paled in comparison.

All this energy would have generated massive amounts of heat that boiled the oceans causing up to tens of meters of water to evaporate. It will also raise air temperatures by up to 100 degrees Celsius.

The sky would have turned black, choked with dust and particles. If sunlight had not penetrated the darkness, simple life on land or in shallow water that relied on photosynthesis would have been wiped out.

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

But what Professor Drabon and her team found next was surprising. Rock evidence showed that violent disturbances led to the production of nutrients such as phosphorus and iron that fed simple organisms.

“Not only was life resilient, but it bounced back very quickly and thrived,” she says.

“It's like you brush your teeth in the morning. It kills 99.9% of the bacteria, but by the evening it's all back, right?” She says.

The new findings suggest that the large impacts were like giant fertilizers, sending essential ingredients for life like phosphorus across the globe.

It's also possible that the tsunami that swept across the planet brought iron-rich water from the depths to the surface, giving early microbes extra energy.

Professor Drabon says these findings add to the growing view among scientists that early life was indeed supported by the violent succession of rocks that struck the Earth in its early years.

“It appears that post-impact life actually faced really favorable conditions that allowed it to flourish,” she explains.

The results were published in the scientific journal PNAS.