The fall of an asteroid to Earth is a global cataclysm. It has 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. The Permian extinction, although not well known to the general public, was much more tragic than the famous extinction of the dinosaurs seventy million years ago.
In the first case, up to 96% of the species of marine organisms (both plants and animals) died out. On land, things were not much better: seventy percent of terrestrial vertebrate species and eighty-three percent of insect species perished. There has never been such a mass extinction of insects in nature, as these arthropods are extremely adaptable to environmental changes.
The second catastrophe was much less destructive, although then there was also a replacement of the biological dominant, which led to the appearanceand 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.
The Wilkes Land Crater is five hundred kilometers in diameter. It is completely hidden under the ice shell of Antarctica, so it is not yet possible to study it.
But in 2009, its radar study was carried out, and it turned out that it has a shape characteristic of impact craters formed at the site of an asteroid or large meteorite impact. The Chicxulub crater is much smaller and has a diameter of one hundred and eighty kilometers. That is, the scale of extinction of terrestrial organisms directly depends on the size of the fallen asteroid.
Astronomers do not have a common opinion about which impact event is the fall of an asteroid, and which is the fall of a meteorite, comet or something else. Sky researchers cannot decide in any way which celestial bodies should be attributed to asteroids, and which to meteorites and even to planets. Seven years ago, pundits decided to isolate a new class of celestial bodies. Several large asteroids and Pluto, demoted from the rank of real planets, were recorded in it. They decided to name the class "dwarf planets". The innovation is not generally accepted, as many astronomers dispute the usefulness of the new classification.
The event that happened in mid-February stirred up Russia, and especially the Urals. A meteorite that fell in the vicinity of Chelyabinsk,experts from NASA consider the largest observed by mankind after the Tunguska.
In the memory of people, this was the meteorite that caused the most destruction and injury. Although he fell apart before reaching the Earth, he managed to do a lot of trouble, even destroying the shop of one of the Chelyabinsk factories. There were reports in the press that this meteorite is a harbinger of an asteroid that will fly near the Earth, and there is a possibility that it will fall into the field of gravity of our planet.
It is interesting that meteorites in the Urals are becoming something almost familiar, their own, dear. The relatively small Chelyabinsk region (less than ninety thousand square kilometers) has become the center of attraction for guests from outer space for the last seventy-five years. In 1941 and 1949, in the city of Katav-Ivanovsk and the village of Kunashak, located in the north of the region, meteorites also fell, although much smaller in size. All three impact sites 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 in such a short period of time is not found anywhere else in the world. Well, just some kind of mysticism!
The incident in the Urals showed that we are defenseless against bombardment from space. Russia has begun developing a ten-year program to protect against space threats.
