Asteroid danger? Research into the bombings is ongoing – the expert is relaxed despite the “observation gap”.

There are countless asteroids known to mankind in the solar system. They may have made life on earth possible today. However, an impact could be catastrophic.

Frascati/Noordwijk – These are remnants of the formation of our solar system. Humanity might not have come into existence without them, but it is nonetheless threatened by them: Asteroids may have brought the basis of all life to earth – but an impact today could have devastating consequences . Humanity is not, however, defenseless. “This is the only natural disaster that we can calculate in advance,” said Detlef Koschny, asteroid expert at the European space agency ESA in Noordwijk, the Netherlands, on International Asteroid Day on 30 June. An asteroid bombardment like in the blockbusters is no longer pure fiction. For some tracks, however, there are huge observation gaps.

Asteroids: more than 20,000 “Near-Earth Objects”

According to the US space agency Nasa, there are more than one million known asteroids in our solar system, of which more than 20,000 are so-called near-Earth objects (NEOs) that pass through our Earth orbit during their orbit. orbit. Two well-known events show what such chunks can do: On June 30, 1908, the shock wave from an asteroid explosion probably swept through millions of trees at Tunguska in Siberia in an area nearly the size of the Saarland. In view of this event, the United Nations then proclaimed June 30 as International Asteroid Day. In February 2013, an asteroid about 20 meters in size and moving at 66,000 kilometers per hour exploded above the city of Chelyabinsk. Around 1,500 people were injured in the blast, mostly from shattered glass. Thousands of buildings were damaged.

Asteroids: They Could Have Made Life On Earth Possible In The First Place

But asteroids also have a silver lining: Millions of years ago, bits of rock and metal from space might have made life on earth possible in the first place. The models said there would be much less water on Earth if there had been no external supply, Koschny explains. It does not come from comets. “The water type is wrong. What’s left are asteroids.” It’s at least a common theory that they brought water to Earth.

The evolution of life on our planet was certainly strongly influenced by a later event: the impact of a twelve kilometer wide chunk in Mexico 60 million years ago is believed to be the cause of the extinction. dinosaurs. This is the only reason mammals would have managed to assert themselves afterwards, says Koschny.

Asteroids: NASA wants to test the launch of celestial bodies

And today? Glowing objects are constantly visible in the night sky: dust and small rock fragments from space burning in the atmosphere. “The total mass that descends to earth is estimated at 100 tons per day,” says Koschny. Large chunks can still present a hazard. The warning protocols take effect from a height of about 20 meters, specifies the chief coordinator of defense against asteroids at ESA, Richard Moissl, whose team works in Frascati near Rome.

ESA and NASA want to study asteroid bombing as a possible defense option. NASA’s “Dart” probe, which has already been launched, is due to touch the smaller piece of a twin asteroid in September and shift its orbit slightly around the larger one. The ESA mission “Hera” should start in 2024 and carry out measurements there.

Asteroids: “observation gaps” must be filled

However, experts still see gaps in asteroid monitoring. According to Koschny and Moissl, observations are still almost exclusively made from Earth. “In the future, we will need space telescopes to have a better early warning system,” says Moissl. “We need to close the observation gaps.” Big chunks aren’t the problem. “The objects we all think we know,” says Koschny. “What an existing threat is in the 20 to 40 meter range.” With an object 40 meters above a larger city, you should evacuate it – and in that size range you only know a few percent of possible candidates.

But people don’t have to be scared and anxious right now. “I can rule out a threat to civilization at this time,” Koschny says. And Moissl doesn’t see anything serious happening on earth at the moment either. “Actually, I can sleep just fine right now.” (dpa)