When Earth was struck by a "stone" of 11,000 tons of space on February 18, 2013, about 1,200 people were injured. And it came without warning.
Now the boss warns the US space agency Nasa, Jim Bridenstine, to make it happen again.
"This is not Hollywood. It's not about movies. Ultimately, it's about protecting the only planet we know of today that has life, Bridenstine said in a speech in Washington D.C. on Monday.
The space stone that entered the Earth's atmosphere on the Russian metropolis of Chelyabinsk in 2013 was as good as a London bus. And even if it did not hurt anyone on the ground, the pressure surge after it had been so strong that the buildings collapsed.
And windows were crushed.
It was then that Most people who were injured were injured. The soundtrack came a long time after the brilliant meteor knocked down thousands of windows, where the onlookers stood and watched what had happened.
Many have the glass divider in front of the face.
In addition to who was injured, parts of a brick building in Chelyabinsk collapsed.
Now the Nazi leader points out that this may happen again.
– I wish I could say that these events are unique, but they are not, said Bridenstine before a conference, writes CNN.
A similar event occurred on June 30, 1908, when another space stone, as unexpected as 2013, entered the atmosphere over Tunguska in Siberia and knocked down trees over a large area such as half of Gotland.
At that time, no one was injured, but the explosion of the explosion threw people who were several kilometers from the place to the ground.
Smaller rocks are much more common and light up the sky over Sweden several times a year.
One of these, one called Bolid, passed an area between Vättern and Vänern, between Mariestad and Laxå, at 10:14 pm on April 29, and was caught by several cameras guarding the sky. One of them as far as eastern Norway.
University of Uppsala, Whoever commands several cameras that monitor the sky, notes that the witnesses describe it as a ball of greenish fire that eventually divided into five to eight parts after lighting for five seconds.
The photo above shows the photo taken by one of the university's cameras, located in Örebro.