New research by American geophysicists overturns our understanding of exactly how dinosaurs died

Discussions surrounding the causes of the great extinction at the Cretaceous-Paleogene boundary have not subsided for decades. Scientists have long debated what exactly delivered the fatal blow: a nuclear winter caused by soot clouds, catastrophic eruptions of the Deccan Traps in modern-day India, or a combination of these disasters.

A publication in the authoritative journal Journal of Geophysical Research: Biogeosciences brings the hypothesis of global fires and extreme heat back into focus. A team of researchers led by Brandon Johnson from Purdue University discovered a previously ignored factor — a colossal amount of microparticles that, along with glass spherules, turned the atmosphere into a true oven.

66 million years ago, an asteroid crashed into Earth in the area of the modern Gulf of Mexico. It had a diameter of up to 13 kilometers, and the power of the explosion, according to scientists' calculations, was 100 teratons in TNT equivalent. The Chicxulub meteorite formed a crater about 20 kilometers deep and about 180 kilometers in diameter.

Tons of rock instantly vaporized from the impact. This superheated vapor rose into the atmosphere, partially cooled, and began raining back down on the planet as a fiery glass tsunami of tiny spheres — spherules.

Previously, it was thought that the excess of this heat should have simply escaped into space. But scientists have found that almost half of the cosmic gas turned into fine silicate dust that hung in the air. This curtain was so dense that it effectively blocked the exit of infrared radiation into space, reflecting heat back onto the planet's surface.

The power of the heat impact was apocalyptic. To visually assess the scale of the catastrophe, the authors used the commonly accepted human survival threshold: a heat flux of 10 kilowatts per square meter for 150 seconds guarantees 100% human death. Taking into account the dust screen, the radiation dose that hit the dinosaurs exceeded this deadly threshold by 17 times.

Animals in the open air died not only from terrible burns but also from instantaneous heatstroke. In addition, the air became so hot that dry grass, needles, and lichens began to spontaneously combust, provoking forest fires.

Ancient fish, whose fossils were found in the Tanis River in North Dakota, witnessed this horror. They died within the first few hours of the catastrophe and forever recorded the chronology of the tragedy. Scientists found trapped glass spherules in their gills, which the fish convulsively swallowed with water as they fell from the sky. And directly above the layer with the fish settled that same clay layer with cosmic iridium, but already without glass spheres. Similar deposits in the Raton Basin in New Mexico confirm the global nature of this phenomenon.

This clear division proved: first there was a glass rain, and then the planet was covered for a long time by a dense "blanket" of dust.

Only those creatures that could temporarily hide underground or underwater were able to survive this hell. That is why, of all dinosaurs, only birds survived, whose ancestors knew how to burrow or swim, and plants were able to regenerate thanks to underground roots and seeds.

This discovery may close the long-standing debate about the causes of the extinction. The cosmic alien and its deadly dust were to blame for everything, and the climatic effects from volcanoes were simply unnecessary — the asteroid did all the dirty work itself.

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