Scientists have long accepted that an asteroid that struck the earth 66 million years ago contributed to the extinction of the dinosaurs.
But there are countless theories about what exactly happened to our planet and its prehistoric inhabitants after impact. Some explanations for the disappearance of dinosaurs blamed on clouds of debris and soot that exposed the sun and cooled the planet, while others say it was harmful gases from worldwide volcanic eruptions or even a major plague.
According to a new study in the journal Proceedings of the National Academy of Sciences, global cooling was the culprit. The impact, the research found, the asteroid Chicxulub ̵
The dinosaurs then fried and froze, Sean Gulick, the study's lead author, said in a press release.
Survey of the Chicxulub Crater
To better understand what happened on the fateful day in the history of our planet, the researchers behind the new study conducted an in-depth investigation into the Chicxulub striker – a challenging achievement , considering that the crater extends 12 miles into the depth of the Gulf of Mexico.
Gulick and his colleague Joanna Morgan collected rock samples there in 2016, from a part of the crater in which rocks and debris were deposited shortly after the impact of the asteroid. No stones from that area had ever been mined before.
Gulick and Morgan then spent the next three years analyzing the samples to geologically reconstruct a timeline of what happened after the impact.
"It's an expanded record of events that we were able to recover from the landmark," Gulick said.
The asteroid hit with the force of 10 billion atomic bombs
So their timeline showed:
Within a minute of impact, the asteroid had pierced a hole nearly 100 miles wide in the seabed, creating a bubbling pit of molten rock and super hot gas . The contents of the fiery cauldron skyrocketed and created a mountain high plum.
The plume collapsed within minutes, solidifying into rippling peaks of lava and rocky material. These peaks were then covered by more stones, traces of burnt land and coal which were transported there by sea waves.
The presence of coal, the researchers said, is proof that fires are ignited after impact; some of the fires probably started hundreds of miles away from the impact crater.
The authors estimated that the asteroid's power corresponded to 10 billion of the atomic bombs used in World War II.
The spacecraft would have evaporated the surrounding land and sent seawater away from the impact site at the speed of a jet, Gulick said. That water formed a tsunami, hundreds of feet high, that might have gone as far as today's Illinois before returning.
Gulick told Newsweek that the space rock would have come in at a rate of more than 12 miles per second, so even dinosaurs 1,000 miles away from the point of impact probably did not live long before the heat reached them.
"Effectively within 1500 kilometers you would have seen very little before you were burned," he said.
Impact released billions of tons of sulfur into the atmosphere
Dinosaurs were not the only creatures that disappeared after the Chicxulub hit. Flying pterosaurs and marine predators such as mosasaurs and plesiosaurs also disappeared along with 75% of life on the planet.
Read more: T. rexes and other dinosaur skeletons look almost alive in a new set of remarkable photos
Many creatures, of course, died near landmark, but the mass extinction associated with the asteroid was probably a result of what happened in the atmosphere after the impact.
According to Gulick's team, the impact evaporated sulfur-rich rocks, releasing a haze of gaseous sulfur in the air that exposed the sun and cooled the planet.
The researchers came to this conclusion because the samples they revealed contained lots of sandstone, limestone and granite but lacked sulfur-rich stones, although stones near the impact site should be filled with sulfur. So they estimated that at least 357 billion tonnes (325 billion tonnes) of sulfur gas entered the atmosphere.
By comparison, the 1887 eruption of Krakatoa volcano erupted about a quarter of sulfur into the atmosphere as a dinosaur-killing asteroid. And the volcanic eruption cooled the earth by 2.2 degrees Fahrenheit for five years.
The effects of the Chicxulub asteroid almost certainly lasted much longer than Krakatoas, Gulick said.
As for Chicxulub, he told Newsweek, "global temperatures would start to drop as a sulfate aerosol haze surrounds the planet."
"The earth would probably no longer look like the familiar blue marble from space," he added, "and it may take as long as two decades to completely clear again."