Talking about how the dinosaurs disappeared, many people recall pictures in which tyrannosaurs and brontosaurs flee from the falling fire rain, and forests are blazing behind them. Perhaps some of the dinosaurs really died from the direct impact of a meteorite, however, as scientists recently found out, most living creatures then died for a completely different reason.
The study was dubbed "The First Day of the Cenozoic Era." We are talking about the current era of the geological history of the Earth, which has lasted for 66 million years. For comparison - Homo sapiens separated from other humanoid animals only 6-7 million years ago, and fully formed as a species only 200,000 years ago.
The beginning of the Cenozoic era is due to the mass extinction of species at the end of the Cretaceous period - it was then, in fact, that the dinosaurs became extinct. At the same time, flying lizards, most mollusks and small algae, as well as almost all large and medium-sized animals that moved on land, died.
There are a huge number of theories why this mass extinction of animals and plants occurred - up to a massive epidemic or due to the appearance of flowering plants. However, the main version is still the hypothesis of the impact - that is, the fall of the asteroid. At the same time, the exact place of the fall is even called - this is the Chicxulub crater on the Yucatan Peninsula in Mexico.
This version is supported by the analysis of the geological layers of the Earth - studies have shown that this crater was formed about 65 million years ago and it was in the same layer of the earth that an increased content of iridium was found throughout the earth, which is in the mantle and core of the Earth, but almost never happens in the surface layer. That is, it was then that the greatest cataclysm occurred, which made all life on Earth completely change.
The results of the study, which was carried out jointly by more than 300 scientists, were published at the end of September 2019 on the PNAS website. Judging by the size of the crater, it was not just a meteor shower, but a huge block that fell from the sky - according to various calculations, from 11 to 80 kilometers (!) In diameter. From the impact with the surface of the earth, the stones began to literally melt, and the entire surface around the place of the fall for some time from solid became liquid.
On the first day, everything around the fall of the asteroid became incredibly hot - the water evaporated, the stones melted, all living things died from fire and heat. However, what happened next was always based only on assumptions. To find out this question, scientists began to drill the ground both in the crater itself and beyond, in order to take samples of the soil and find out this issue.
So, scientists found out that in the mineral rocks in the entire area around the crater there is a very high sulfur content. And in the crater itself there is almost no sulfur. It was this discovery that made it possible to look at those events from a different angle. Not a huge tsunami killed dinosaurs and other living things, not global fires, and not even the asteroid impact itself - but a global cooling caused by the evaporation of sulfur.
“The real killer could only be the atmosphere itself,” says Sean Galik, the scientist who led the study. "The only way to cause mass extinction is to influence the atmosphere itself."
Sulfur can seriously affect the climate. Thus, the eruption of the Tambora volcano in 1815 triggered an event throughout the earth known as the "Year without Summer".It took several months for the ash to spread through the earth's atmosphere, so in 1815 the effects of an eruption in Europe were not yet felt so strongly. But in 1816, the weather was unusually cold throughout western Europe and North America. In the United States, this year was even nicknamed "eighteen hundred and froze to death". There were frosts in America in June and July. Snow fell in New York and New England. Snow fell every month in Switzerland.
Some scientists are proposing to use this effect of sulfur on the atmosphere to cope with global warming. And then, 66 million years ago, there was so much sulfur in the atmosphere that all large animals began to freeze and gradually die out. In addition, the fall of the asteroid provoked the rise of dust and vapors into the air - it is believed that then 15 trillion of ash and soot were suspended in the air, so that in addition to cold, it was also dark on Earth.
The consequences of an asteroid collision with Earth were unambiguously dramatic. However, it was this collision that ultimately liberated many species niches, which were subsequently occupied by mammals, including humans.
You can learn about what meteorites look like and what they are made of by visiting Namibia, where it is still located Goba meteorite.