If an asteroid crashes into the ocean, will a tsunami appear?

If an asteroid crashes into the ocean, will a tsunami appear?

Integrated computer modeling has recreated the picture, and the results may surprise you.

15 years ago, Galen Gisler felt with his gut that something was wrong in the way Hollywood portrays the fall of an asteroid into the world's oceans.

“Films such as Clash with the Abyss and Armageddon suggest that this will lead to a devastating tsunami that will take everything along the coastline surrounding the ocean basin. But I was skeptical, ”said Gisler, a scientist at the Los Alamos National Laboratory in New Mexico.

In general, a collision with an asteroid is not the best day for the Earth, although it is part of the natural cycle of life in a dynamic and developing Solar System. Cosmic marauding stones plow interplanetary space without taking into account the precious terrestrial biosphere. If they want, they can crash into us, and sometimes the consequences are dire.

If an asteroid crashes into the ocean, will a tsunami appear?

Depending on the location of the fall, the situation is different. If you predict the appearance of the object and the place of defeat, for example, near the big city, then we would have managed to evacuate people, but the damage to society, infrastructure and the economy would be terrible. But, what if he gets into the ocean? After all, the surface is 70% filled with liquid and this is the most likely scenario. But this option is still a little studied. Gisler was going to better explore the realities of a massive impact on the ocean, and presented the results of his team at the autumn meeting of the American Geographical Union in San Francisco last week. He demonstrated astounding data from a 3D model of an asteroid fall. This proved that Gisler’s initial doubts were true: the monstrous cine tsunami was an invention, part of the science fiction plot.

“The impact carries a point effect and will only affect the immediate area around the point of impact. And to create a tsunami, you need to disturb the entire water column, ”he said.

It is like throwing a stone into a pond. Of course, the energy from the impact will create waves, but this ripple is dispersive. That is, it loses its energy very quickly. In the ocean, the waves are localized and there is not enough energy to create a tsunami.

Tsunami occurs when large-scale mass shifts on the sea day (underwater earthquake or landslide). They lead to a huge movement of a massive water column from the seabed to the surface, reaching wavelengths of 100 km and more. And this is many times more than the depth of the ocean (several km). Tsunamis are not very dispersive and do not lose energy during their journey to the coastline.

But this does not mean that the asteroid impact will go unnoticed.

“Splashes will reach tens of kilometers,” added Gisler. In accordance with the model, the jet will protrude above the surface for several kilometers, producing a rim of waves surrounding the crater of transitional water, rising to 400 meters in height. “It's terribly high! But if this does not happen close to the shore, then there will be no danger. ” In addition, a significant part of the kinetic energy of the asteroid will evaporate a large amount of water. And this is a powerful greenhouse gas that can persist in the stratosphere for several months or years, which will affect global climate change.

Powerful shock waves and strong winds also wreak havoc on the surface, so the further the strike from the populated coastal areas, the better.

Hisler's research broadens the understanding of the influence of space objects on the Earth. So, if their size is 300 meters or less, then the ocean can be used as a planned strike site to limit damage.

“We get new opportunities. If we cannot stop the strike, then at least we will deflect it to the middle of the ocean, ”he says.

Although NASA and other agencies are trying to track the approach of dangerous objects, problems may arise with the elimination of the threat. The ocean is a fairly successful solution.

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