This is not a “nuclear winter”: scientists told how an asteroid led to the extinction of dinosaurs

The asteroid that destroyed the dinosaurs was not the cause of the long "nuclear winter", scientists from the University of Utrecht (Netherlands) found out. There is no evidence of severe global cooling in the long term. Study this was published in the journal Geology.

One spring day 66 million years ago, an asteroid about 10 kilometers in diameter crashed into the peninsula Yucatan, forming a crater almost 20 kilometers deep. This led to a mass extinction on Earth, which resulted in the extinction of 75% of species, including dinosaurs.

But how exactly the asteroid killed the dinosaurs remains a mystery. It is unlikely that they were all at once in the asteroid impact zone, the researchers note. It is generally believed that the impact threw so much dust and dirt into the atmosphere that it caused a "nuclear winter" - a period of prolonged cooling during which global temperatures plummeted.

Now scientists have proposed a new theory: the disaster did not lead to a prolonged cold snap, but to a shock wave in the food chain.

The authors of the study analyzed bacteria fossilized in coal samples before, during and after the asteroid impact. As a rule, they react to changes in temperature - thicken or thin their cell walls, "like putting on or taking off a blanket." And, as it turned out, after what happened 66 million years ago, microorganisms did not gain mass for wintering. What's more, scientists have found an approximately 5,000-year warming trend.

The dust kicked up by the asteroid could have lingered in the atmosphere for only a decade or less. This could change the global temperature, but only for an insignificant period, which is not so critical. At the same time, the catastrophe was supposed to plunge the Earth into darkness for the same period, and most of the earth's fauna could not survive this. The chain could be like this: plants die without sunlight, herbivores are left without food and die, and behind them are the predators that fed on them.

In other words, a "nuclear winter" is not out of the question, but it didn't last the 1,000 years it was supposed to, and it didn't cause the extinction of the dinosaurs.

The researchers now plan to study coal from elsewhere in the US to piece together data on temperature changes over the millennia leading up to the asteroid impact.