In fact, asteroids that have fallen to the earth a lot
Just as dinosaurs were destroyed by the collision of giant asteroids, catastrophic asteroids often come to Earth.
That’s why NASA is observing near-Earth objects (NEOs) and has plans to defend them (DART).
However, this is a story of a huge asteroid with a scale of several tens of kilometers that might destroy humankind.Asteroids smaller than 100 meters can only be discovered hours to months before the Earth’s collision because it is too dark.。
And most asteroids have fallen to Earth without even being found.
The other day, I introduced the news that the asteroid “2022 EB5” discovered on March 11, 2022 collided with the earth two hours later.
The asteroid discovered on March 11 was colliding with Earth two hours later!
This is the fifth example in the history of asteroid observations discovered before the collision.
Some may wonder why asteroids rarely fall, so that’s what they are.
But that’s not really the case.Asteroids are falling to Earth in larger quantities than expectedIt is.
The image below was compiled by NASAMap showing asteroid fall locations and their explosion scale reported from April 15, 1988 to January 11, 2022am.
Please note that this is just the number reported, not all of the asteroids that have collided with Earth.
The asteroid “2022 EB5” the other day is not counted on this map, but it is said that the explosion of this asteroid had energy equivalent to 3kt in TNT equivalent.
This is mainly shown by the green circle on the map above, which is an asteroid explosion of the same scale.
When it becomes yellow, it is 15 kt in TNT equivalent, and when it is orange, it is 30 kt.Will be.
The most prominent red circle was the largest in recent years.A meteorite that fell in Chelyabinsk, Russia in 2013, and its explosive energy was 500 kt in TNT equivalent.It has been with.
If you explain to those who can not imagine even if it is said to be TNT equivalent, many people witnessed it in the video in 2020The port explosion in Beirut, the capital of Lebanon, was equivalent to TNT 1.1kt.Is estimated to be.AlsoIt was equivalent to the Hiroshima-type atomic bomb of 15 ktIs estimated to be.
In other words, it is estimated that the Chelyabinsk meteorite had an explosive energy equivalent to 30 times that of the Hiroshima-type atomic bomb.
The fact that such an explosion did not cause catastrophic damage isSmall asteroids explode in the air at very high altitudesBecause.
It is believed that the Chelyabinsk meteorite was regarding 15 meters in size, and because it exploded in the air at a high altitude of 15 km or more, only part of the shock wave reached the ground.
Even so, damage such as the window glass of the building breaking and the roof breaking due to the shock wave has been reported on the ground, and a brighter glow than the sun was confirmed within 100 km of the explosion, and people who were outdoors were burned by the heat rays (ultraviolet rays). It is also reported that it was done.
Surprisingly less coverage of the fall of an asteroid to the data compiled by NASA is simply because it did not fall into a populated area.
Much of the Earth’s surface is the ocean, and the area where many people live is limited, so so far no asteroid has fallen directly above a modern city.
It is estimated from the analysis of this Chelyabinsk meteorite that the Tunguska event, in which trees were knocked down over a wide area, was an aerial explosion of a 60m-scale asteroid, but it also occurred in a remote area.
Space agencies such as NASAI’m just lucky that I haven’t suffered much damage on a small asteroid so far.I think it is.
If a Tunguska event at the level of a big explosion occurs over a modern city, the damage is immeasurable.
However, as you can see from the news of the asteroid “2022 EB5” the other day,Asteroids on the scale of several meters to several tens of meters can hardly be seen at a position far from the earth, so there is a high possibility that they will collide with the earth within a few hours following they are discovered.It is.
So what should we do in this situation?