Nearly 80 kilometers of the Chilean coast are covered with elongated fragments of desert glass, which scientists who have recently studied them say stem from a comet explosion over the Atacama Desert about 12,000 years ago.
The explosion was what is called an air eruption, which can occur when an object such as a meteor or comet falls to Earth. These objects heat up due to friction with our planet’s atmosphere. While some burn completely into the atmosphere, other objects explode when they come in contact with thicker parts of the atmosphere. They can make the ground temperature as hot as the Sun, with winds outside the hurricane.
Such was the case for a comet that fell to Earth during the late Pleistocene, according to the research team that studied the composition of the silicate glasses scattered around Chile’s Atacama. They found that the explosion of the fireball caused pieces of space stone to melt together with the molten earth below and form glass. Their findings were published this week in Geology.
“Atacama is perfect for maintaining the record,” Peter Schultz, a planetary geologist at Brown University, told Gizmodo in an email. “The difference between other glasses across Atacama and these glasses is that our glasses are really large and indicate complex interactions between air eruptions, heating and wind.
“In other words, it teaches us the details of the event for the first time,” Schultz added. “We actually have several glasses in Argentina of much older ages, but can show that these were produced by actual collisions.”
Earlier, another team believed the glasses came from old grass fires, long before the area became desert, burning hot enough to transform the ground. But the latest team suspects that an extraterrestrial object is the source of the geological strangeness due to the glass’s unique mineral structure and structure, which showed signs of being bent and transformed while still floating. These details have been observed in other pneumatic remnants and would not look so violent in lawn fire glasses.
In addition, the team found minerals that come from other space rocks, such as troilite and cubanite. Such inclusions are similar to those collected by NASA during the Stardust mission from dust from the Wild-2 comet in 2004.
“Those minerals are what tell us that this object has all the markings of a comet,” said Scott Harris, a planetary geologist at the Fernbank Science Center and a co-author of the study, in a Brown University publication. “Having the same mineralogy that we saw in the Stardust samples brought about in these glasses is a really powerful proof that what we are seeing is the result of a cometic air eruption.”
The current age estimate of airburst remains an ongoing work on the test front. The youngest date estimate, made by another co-author, was about 11,500 years ago. “There is also a chance that this was actually seen by early settlers who had just arrived in the region,” Schultz said in the same release. “It would have been something of a show.”
If not for humans, depending on the timing, one must have pity on the doomed giant earth lazy animals and other megafauna in the area. They would have been burned to crisp in an instant.