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Two asteroids that struck Earth within 25,000 years of each other did not have a long-term impact on the planet, researchers have found. The first asteroid hit a place that is in Russia today and created a crater 60 miles wide. The other impact happened in the Chesapeake Bay on the US's East Coast about 36 million years ago.
The study was published in Communications Earth & Environment.
The craters made by the asteroid strikes are one of the biggest to have formed on Earth, yet they did not cause any major climate change over the following 150,000 years.
Bridget Wade, the study's co-author, "These large asteroid impacts occurred and, over the long term, our planet seemed to carry on as usual."
"We were expecting some kind of climate perturbation, most likely cooling to result from the impacts, so we were surprised to find no climatic response," Wade told Newsweek.
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The researchers found fossils of ancient creatures in the seafloor and examined the isotopes in them. These isotopes helped them learn about the climate of the time.
"The fossils are about the size of a grain of sand (0.5 mm) and we can separate them into different species under the microscope," Wade said.
Climate remained stable over the years
They were surprised to see that despite such massive asteroid strikes, Earth's climate managed to remain stable. But the team clarified that they only had access to study long-term climate changes. The immediated consequences of the impacts might have been devastating, especially if considered over a human lifetime.
"Our study would not have picked up shorter-term changes over tens or hundreds of years, as the samples were every 11,000 years," Wade said. "Over a human timescale, these asteroid impacts would be a disaster."
The study found that the asteroids were quite small, just about five miles wide. Yet, they managed to gouge such huge craters, which indicates how forceful the impacts were. In the short term, tsunamis would have wreaked havoc, with widespread fires taking over Earth. The asteroid strike likely created massive clouds of dust that blocked sunlight for a brief time.