The end of the world wouldn't be pretty.
If a big asteroid — like the one whizzing by on Wednesday — slammed into the Earth, ferocious winds of up to 1,000 mph and intense shock waves would kill the most people, according to a study published Wednesday.
Researchers looked at seven effects associated with asteroid impacts — heat, pressure shock waves, flying debris, tsunamis, wind blasts, seismic shaking and cratering — and estimated how deadly each would be. The winds and the shock waves would be the worst.
In fact, these two effects would account for more than 60% of lives lost, said Clemens Rumpf, study lead author and a researcher at the University of Southampton in the U.K. Shock waves from a spike in atmospheric pressure would rupture internal organs, while wind blasts would hurl human bodies and flatten forests.
“This is the first study that looks at all seven impact effects generated by hazardous asteroids and estimates which are, in terms of human loss, most severe,” Rumpf said.
Also, unlike in Hollywood movies, land-based impacts would be far more dangerous and deadly than asteroids that landed in oceans, the study found. Though a tsunami might be triggered, the waves would likely dissipate before reaching land, unless the impact was just offshore. Overall, tsunamis would account for 20% of lives lost, according to the study.
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The study, which used computer models to batter the globe with 50,000 artificial asteroids ranging from 49 to 1,312 feet across, only considered the immediate effects of an impact. "Larger asteroids would also be expected to cause long-lasting environmental changes, such as dust deposition in the atmosphere and subsequent dimming of sunlight," he said.
Long-term effects would most likely be the main issue with larger asteroids: The injection of huge masses of dust and gases into the atmosphere would effectively block out sunlight for long periods of time, to the point that most life could not be sustained, according to NASA. This is what may have happened to the dinosaurs about 66 million years ago, thanks to a six-mile wide asteroid.
Fortunately, asteroid impacts are very rare: An asteroid that's more than 1,300 feet in size, like the one zipping by the Earth on Wednesday, is likely to strike the planet only once every 100,000 years, according to Rumpf.
“The likelihood of an asteroid impact is really low,” Rumpf said. “But the consequences can be unimaginable.”