The fall of an asteroid to Earth is a cataclysm of global proportions. It always led to changes in the climate of our planet, due to which a huge number of species of living organisms died out. According to one of the most reliable hypotheses, it was the fall of the asteroid that caused the Permian mass extinction about two hundred and fifty million years ago. Permian extinction, although not very well known to the general public, was far more tragic than the famous extinction of dinosaurs seventy million years ago.
In the first case, up to 96% of species of marine organisms (both plants and animals) became extinct. On land, things were not much better: seventy percent of terrestrial vertebrate species and eighty-three percent of insect species died. There was no longer such a mass extinction of insects in nature, since these arthropods are extremely easy to adapt to environmental changes.
The second catastrophe was much less destructive, although then the biological dominant also took place, which led to the emergence and development of mammals. Hypothesis number one is also the fall of an asteroid. In the first case, scientists point to the Wilkes Land Crater in Antarctica, which, in their opinion, was formed from the fall of this asteroid, in the second - to the Chicxulub Crater in Mexico.
Wilkes Land Crater is five hundred kilometers in diameter. It is completely hidden under the ice shell of Antarctica, so it is still impossible to study it.
But in 2009, his radar study was carried out, and it turned out that it has the shape characteristic of impact craters formed at the site of the impact of an asteroid or large meteorite. Chiksulub Crater is much smaller and has a diameter of one hundred eighty kilometers. That is, the scale of extinction of terrestrial organisms directly depends on the size of the fallen asteroid.
Astronomers have no consensus on which impact event is the fall of an asteroid, and which is the fall of a meteorite, comet, or something else. Researchers of the sky can not decide which celestial bodies should be attributed to asteroids, and which - to meteorites and even planets. Seven years ago, pundits decided to single out a new class of celestial bodies. It recorded several large asteroids and demoted from the title of the real planets Pluto. They decided to call the class "dwarf planets." The innovation is not generally accepted, since many astronomers dispute the appropriateness of the new classification.
The event in mid-February stirred up Russia, and in particular the Urals. The meteorite that fell in the vicinity of Chelyabinsk, NASA experts consider the largest of the observed humanity after the Tunguska.
In people's memory, it was a meteorite that caused the most damage and injuries. Although it fell apart, not reaching Earth, he managed to do a lot of troubles, destroying even the workshop of one of the Chelyabinsk factories. In the press there were reports that this meteorite is a harbinger of an asteroid that will fly near the Earth, and it is likely that it will fall into the gravitational field of our planet.
It is interesting that meteorites in the Urals become something almost familiar, their own, native. The relatively small area of Chelyabinsk region (less than ninety thousand square kilometers) over the past seventy-five years for the third time becomes the center of attraction for visitors from outer space. In 1941 and 1949, meteorites also fell in the city of Katav-Ivanovsk and the village of Kunashak located in the north of the region, albeit much smaller in size. All three places of incidence can be connected by an almost straight line no more than two hundred and fifty kilometers long. Such a concentration of meteorites in a limited area for such a short period of time is not found anywhere in the world. Well, some kind of mysticism!
The incident in the Urals showed that we are defenseless before the bombing from space. In Russia, the development of a ten-year defense program against space threats has begun.
