A new study reports that the biggest threat posed by an asteroid falling to earth is not the impact itself, but the shockwave it will generate as it enters the atmosphere.
An air explosion, which will produce an asteroid that burst into the Earth's atmosphere, will be the main killer of people, regardless of whether the asteroid collapses in the air or hits the surface.
Slightly less dire news is that a killer shockwave must occur near a very populated area for the effect to be. And the best news is that huge asteroid impacts are very, very rare.
An ordinary asteroid revolves around the Sun at a speed of 30 km / s. If at this speed the asteroid hits the Earth's atmosphere, a huge amount of energy will be ejected. The shockwave, says lead study author Clemens Rumpf of the University of Southampton in the UK, will produce tornado-force winds that will carry a pile of debris. The asteroid can collapse completely, but if it survives its journey through the atmosphere, it will hit the Earth, forming a crater, scattering debris for kilometers around and causing violent earthquakes. In a nutshell, it will be a very bad day for Earth, especially for those unfortunate people who live near the impact site.
To assess the risk of mortality from asteroids, Rumpf considered three possible impact scenarios: the option when a celestial body burns up before it hits the ground; the case when the object hits the surface; version when an asteroid falls into the ocean and produces a tsunami.
Rumpf drew a graph that shows the different scenarios. He also elaborated on two scenarios. In the first of these cases, an asteroid 200 meters in diameter will strike the Atlantic Ocean off the coast of Rio de Janeiro. Such an event, says Rumpf, would kill about 50,000 people. 75% of the lives will be claimed by the tsunami, 25% will die due to the winds of the air explosion. In the second scenario, Rumpf calculated the death toll in London and Berlin. He considered asteroids of two sizes - 50 and 200 meters wide, and two types of events - an air explosion or an air explosion plus impact.
Scary, the scientist predicts millions of deaths, 85% of which will be caused by the winds of an air explosion - even if the asteroid hits the ground. 15% of the population will die from the heat generated by the air blast. Other phenomena - pressure waves, earthquakes, impact, asteroid debris and tsunamis will kill the rest.
Don't panic! Keep in mind that a blow of this magnitude occurs once every four thousand years. Moreover, most of the planet's surface is uninhabited, so the chances of an asteroid exploding over your city are negligible. Even so, scientists are working to pre-destroy deadly asteroids.
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