What happened to the hot Cheetos asteroids

Astronomy - This is what happens to us when an asteroid hits Earth

This is what happens to us when an asteroid hits Earth

Meter-high tsunamis, tremendous heat and powerful shock waves: Hollywood has often shown what could happen if an asteroid hit the earth. Researchers have now found out which effect is the most devastating for mankind.

They are called "2004 BL86", "2014 JO25" or "2009 JF1" and the majority of people have probably never heard of them. No wonder, most asteroids rush through space far from Earth. But some come pretty close to the blue planet. So far it has turned out to be easy for mankind, but what if apocalyptic science fiction visions of Hollywood become reality at some point?

With asteroids up to 400 meters in diameter, one would have to protect oneself against wind gusts and pressure waves occurring at the same time, researchers have found. The team led by Clemens Rumpf from the University of Southampton in Great Britain has investigated which effect an asteroid impacting on Earth would have the most serious consequences for humans, i.e. most victims.

The study in the journal "Geophysical Research Letters" analyzes the distribution of possible victims according to seven likely effects: tsunamis, flying debris, shock waves, heat, earthquakes, winds and crater formation.

Pressure waves and violent winds

Result: Tsunamis naturally lead to most victims when they hit the sea. Overall, however, this does not pose as great a risk as impacts on the earth. Atmospheric pressure waves that propagate at supersonic speeds and the resulting strong winds are particularly dangerous for the latter.

They are responsible for over 60 percent of the deaths from impacts by asteroids up to 400 meters in diameter. The waves caused by the increasing pressure in the atmosphere and gusts of wind that equalize the pressure differences could throw people through the air and cause buildings to collapse. The wind could exceed the speed of hurricanes.

In their computer model, the researchers let 50,000 asteroids with a diameter of 15 to 400 meters - the most likely sizes - hit the earth. The results could help crisis managers prepare for an impending cosmic impact, comments Rumpf in his study. In the event of smaller impacts, the population could seek shelter in cellars, for example, while evacuations would be unavoidable for larger asteroids.

Larger impact is unlikely

According to Rumpf, an asteroid around 60 meters in diameter hits the earth every 1,500 years on average, and an asteroid around 400 meters wide every 100,000 years. "The probability of an asteroid impact is really low. But the consequences can be unimaginable," says Rumpf.

Smaller bodies often burn up in the atmosphere - you usually don't notice anything on the surface of the earth. In 2013, however, a 20-meter meteorite exploded over the Russian metropolis of Chelyabinsk and gave an idea of ​​the effects of such dangerous shock waves: around 7,000 buildings were damaged and around 1,500 people were injured.

The problem: Such small bodies are numerous, often invisible and therefore difficult to observe, says Kai Wünnemann from the Natural History Museum in Berlin. But as Chelyabinsk showed, this danger should not be underestimated either. Precise predictions of when the next body will set course for earth are unrealistic. Such an event could well happen again in the next ten years.

Fortunately, this is extremely rare for large asteroids, which sometimes reach a diameter of ten kilometers and are then referred to as "global killer" ("global destroyer"). The asteroid that killed the dinosaurs around 65 million years ago was one of them. Such a destructive event occurs on average every 100 million years.

World Asteroid Day on June 30th

In order to bring the topic further into the focus of the public, the General Assembly of the United Nations proclaimed June 30th as World Asteroid Day last year. The date marks the anniversary of the largest asteroid impact in recent history: on June 30, 1908, a hit in the Tunguska region in Siberia devastated around 2,000 square kilometers of uninhabited area. According to researchers, the asteroid had a diameter of 30 to 40 meters.

If such a chunk should return course to earth in its trajectory, there are only two options for the European space agency ESA: distract or destroy. There are many suggestions, from solar mirrors to hydrogen bombs. Most of them, however, are not technically or financially feasible. The use of impact projectiles to deflect orbit is more realistic.

Kinetic impactor or simply "buffer stop" is what Wünnemann calls the objects that are to be actively placed in the path of an asteroid on its way to Earth. The joint "Aida" mission of ESA and NASA, which is aimed at asteroid defense, is intended to provide information on this.

"2014 JO25" flew comparatively close to Earth in mid-April, announced the US space agency NASA - but was able to rule out a collision with the 650-meter asteroid early on. The distance was around 1.8 million kilometers or 4.6 times the earth-moon distance.

The closest approach of a comparable asteroid is predicted by NASA for 2027. "1999 AN10" will then rush past the earth at a distance of 380,000 kilometers. Just as dense as the Earth's moon is. That is close, explains Wünnemann. But: "Everything that flies by is not dangerous."