On the anniversary of the fall of the celestial body, the astrophysicist told what the fireball consists of, what its value for science and why it was impossible to defend against it
When residents of the Chelyabinsk region saw a flash in the sky, many thought it was a rocket. And the scientist Sergei Zamozdra immediately realized that it was a meteorite.
- February 15, 2013. I stand by the window. The sensation of the flash - as if the car blinked a high beam. I immediately realized that it was a meteorite. Moreover, literally the day before, I told the students about such phenomena … I immediately ran to the window at the other end of the educational building to trace the trail of the falling car. I called my boss to tell me about the "alien", and at that moment a shock wave comes. Intuitively, I grab the window frame so that it doesn't fly out. The window was literally shaking under my palm, - said Sergei Zamozdra, Associate Professor of the Department of Theoretical Physics of ChelSU, Candidate of Physical and Mathematical Sciences, on the radio Komsomolskaya Pravda.
- Many agreed that we were very lucky?
- How to look. This is both luck and bad luck at the same time. Bad luck is obvious. People suffered. There are injuries, shock. Material damage. Perhaps, there were also long-term consequences - someone developed, for example, chronic diseases.
Luckily, we have a chance to explore this cosmic body in detail. Previously, it was believed that the threat is posed by space objects larger than 100 meters. Ours was "only" 18, and such devastating consequences. Additional funds appeared immediately, and research work was intensified.
A meteorite was raised from the bottom of Lake Chebarkul
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Photo: Valery ZVONAREV / kp.ru
- By the way, where, from what Galaxy, did the car come to us?
- You shouldn't wait for a meteorite from a distant Galaxy. We have enough such "cobblestones" in our home, in our solar system - about half a million of them are already known. Telescopes are getting better, and we are able to find even more of these meteorites. They are cramped in space. They clash periodically. And one of these fragments flew to us in the South Urals.
- Scientists and rocket scientists, it turns out, missed the meteorite?
- Its speed was very high (18 km / s - editor's note), and our means of protection, I think, are not designed to fix such a speed. Moreover, the meteorite flew over the horizon, from the side of the rising sun. It was very faintly noticeable. Therefore, they missed.
WHY METEORITE LOSES IN WEIGHT
- It's been four years. Is our meteorite still being studied or is everything already clear?
“I didn't think the research would take that long. If we take the Tunguska phenomenon, then some fragments cannot be found. Most likely, it was a comet that exploded over the Earth and evaporated, turning into dust. There is actually nothing to learn there.
We still have a bunch of stones. They are sawed, cut. They study magnetic properties, impact of shock waves, chemical properties.
The glow itself is called a fireball. Fragments of a meteorite fall to Earth. The main body fell into Lake Chebarkul. An 8-meter crater formed. Body size is about 80 centimeters.
The meteorite is in the Chelyabinsk Regional Museum of Local Lore
Photo: Valery ZVONAREV / kp.ru
- Is it true that the meteorite, which is now exhibited in the Chelyabinsk Regional Museum of Local Lore, is gradually losing weight, dries up?
- It came as a surprise to me too. I believed that the meteorite is a monolith. It turned out that it also has pores. They absorbed moisture from Lake Chebarkul, where the meteor fell. The moisture evaporates gradually. I would not be surprised that the "alien" lost 10-20 kg in mass.
How to distinguish a meteorite from a simple stone
- Over the past four years, has something like this ever flown to Earth?
- There was nothing comparable. There are cases of falling in Europe, in Khakassia, in Buryatia. The only thing I can say is that literally last year, in the Argayash district of the Chelyabinsk region, villagers found a rather large, five kilo-weight, fragment of a meteorite. Its age is over 100 years old.
- And how to distinguish space fragments from earthly stones? What do you advise?
- Such fragments have a special crust on top. Like burnt pie from the oven. Take it in your hand. The density is very high. Such pieces are three to five times heavier than coal, for example.
Look at the chips. Small light grains should be visible there. The diameter is no more than a millimeter.
Associate Professor of the Department of Theoretical Physics of ChelSU, Candidate of Physical and Mathematical Sciences Sergey Zamozdra
Photo: Valery ZVONAREV / kp.ru
- What does our Chelyabinsk meteorite consist of? Gas, ice?
- Most likely made of rocky material. This is called chondrules - the oldest substance from which the planets were born. A kind of frozen droplets. They stuck together, caked together, shrank. The age of such pieces is billions of years.
- How much are the pieces of meteorites today? What is the price?
- Our Chelyabinsk meteorite is estimated at about 500 rubles per gram. The price of large, heavy pieces can go up to a million rubles and more.
- Not material value …
- When you hold such a piece in your hands, you feel a connection with the cosmos, with some kind of eternity, infinity. It costs a lot. If I had enough funds, I would probably start collecting such stones.
- Surely, as a researcher, you have a piece of the Chelyabinsk meteorite?
- Yes, I found fragments during a scientific expedition. This excitement is worse than hunting. Moreover, it was February. Snowdrifts. I found funnel holes, and at the bottom - pieces of meteorite. The heaviest weight is about 130 grams. With a chicken egg.
Chelyabinsk businessmen took advantage of the sensation
Photo: Valery ZVONAREV / kp.ru
DOES NOT FALL IN ONE POINT TWO TIMES?
- According to the initial reports of the Ministry of Emergency Situations, nothing was found at the site of the meteorite impact on Lake Chebarkul. Why was it not immediately discovered?
- In a couple of seconds, the meteorite "pierced" a ten-meter layer of silt and reached the granite rocks at the bottom of the lake. I went like a knife into butter. Therefore, nothing was found. The conditions are too difficult for the examination.
- They say that if the meteorite entered the atmosphere from a different angle, the destruction could be more significant?
- Then he would have fallen, possibly somewhere in Kazakhstan.
But if it was not stone, like ours, but iron-nickel, like a piece of stainless steel, it would have fallen almost entirely. Not burned out. And the crater would be much more significant.
- And what is the final power of the explosion? What is it comparable to?
- It was finally announced that it was 500 kilotons (kt). This is about three dozen Hiroshima.
- The projectile does not fall twice at one point … Is there a possibility that history will repeat itself in Chelyabinsk?
- Yes, there is such a belief. But meteorites keep falling. Albeit other sizes. So anything is possible.
REFERENCE
Four years ago, on February 15 at about 9:20 local time, a meteorite fell near Chelyabinsk.
According to official figures, 1,613 people were injured then. Most of them were cut through by the blast-shattered glass.
According to various sources, from 40 to 112 people were hospitalized, two victims were placed in intensive care units. Not a single person died.
The shockwave also damaged buildings. The total amount of damage was about 1 billion rubles.
On October 16 of the same year, a fragment of the Chelyabinsk meteorite was recovered from a depth of 13 meters - from the bottom of Lake Chebarkul. Now the exhibit is on display in the Chelyabinsk Regional Museum of Local Lore.
Alexey MIKUSHIN
