A study has suggested that mysterious glass fragments found in Chile’s Atacama Desert are likely to have been created by an ancient, exploding comet.
Scientists discovered that the pieces of black or dark green glass were clustered in a corridor that extends almost 50 miles (75 km) across.
Some are up to 20 inches (50cm big) and look as if they’ve been folded and twisted into their current forms.
It had been thought they could have been created by volcanic activity or ancient grass fires — because the region wasn’t always a desert — but new research led by Brown University has come to a different conclusion.
The study revealed that tiny fragments of glass were enriched with minerals common to rocks of extraterrestrial origin.
Discovery: Mysterious shards of dark green or black glass strewn across Chile’s Atacama Desert (pictured) were likely created by an ancient exploding comet, a new study has claimed
Scientists discovered the dark green and black glass pieces a decade ago. They are now clustered along a large corridor that spans nearly 50 miles (75km).
Researchers said that fragments of glass from this world contain exotic minerals such cubanite and troilite, which are only found in meteorites and other extraterrestrial stones.
These minerals closely match the composition of material sent to Earth by NASA’s Stardust mission. It sampled particles from a comet called Wild 2.
They concluded that the minerals are likely the remains of an extraterrestrial object — most likely a comet — streamed down after an explosion that melted the sandy surface below.
Pete Schultz of Brown University, the study’s lead author, stated that this is the first time there has been clear evidence that Earth’s surface has glasses created by thermal radiation or winds from a fireball exploding just below the surface.
“This was a massive explosion that had such dramatic effects on such a large area.
“Lots of people have seen bolide flameballs streaking across a sky, but they are tiny blips when compared to this.
Researchers collected more than 300 desert glass samples before analysing them under an electron microscope.
The samples were found to have been twisted, folded and rolled while still in molten form.
Researchers believe that this is consistent with an incoming meteor and an airburst explosion. This would have been accompanied tornado-force winds.
They added that the glass was also recyclable. Fragments ‘indicate almost simultaneous (seconds-to-minutes) intense airbursts near Earth’s surface at the end of Pleistocene’ 12,000 Years ago.
The glass is scattered across the Atacama Desert east to Pampa del Tamarugal. It is a plateau in northern Chile that lies between the Andes and the Chilean Coastal Range to west.
These minerals closely match the composition of material sent to Earth by NASA’s Stardust mission. It sampled particles from a comet called Wild 2.
Researchers collected over 300 glass samples before analysing them under an electron microscope.
Minerals in the glass called zircons thermally decomposed to form baddeleyite, the authors said, which would have required extremely hot temperatures of above 3,038°F (1,670°C)
During the Pleistocene, there were fertile areas in the desert with trees and grassy wetlands created by rivers that ran from the east.
It has been suggested that large fires might have been sufficient to melt the sandy soil into large glassy slabs.
The new research showed that this theory is extremely unlikely due to the glass content and other key physical characteristics.
Minerals in the glass called zircons thermally decomposed to form baddeleyite, the authors said, which would have required extremely hot temperatures of above 3,038°F (1,670°C), which is far hotter than a wildfire.
The glass is concentrated in small areas across the Atacama Desert east from Pampa del Tamarugal. This plateau is located in northern Chile, between the Andes Mountains to the east and Chilean Coastal Range on the west.
Researchers found that it contains exotic minerals like cubanite and troilite, which are only found in meteorites or other extraterrestrial rocks.
Scott Harris, a planetary scientist at the Fernbank Science Centre, said, “Those minerals are what tells us that this object is all the markings like a comet.”
“To see the same mineralogy in these glasses that we saw in Stardust samples is powerful evidence that we are seeing the result of a cometary burst.”
The pieces of dark green or black glass are clustered in a vast corridor that stretches almost 50 miles (75km) across Chile’s Atacama Desert (stock image)
Researchers say more work is required to determine the exact age and date of the glass. This would allow researchers to determine when the ancient comet burst in the Atacama desert (pictured).
This is an artist’s impression showing the Stardust spacecraft approaching comet Wild 2 (2004).
Schultz stated that more work is needed to determine the exact age of each glass. This would allow Schultz to pinpoint the exact date.
Experts believe that the impact occurred around the time large mammal populations disappeared from the area.
Schultz stated, “It’s too early to say if the megafauna disappeared or not, but we can say that this event took place around the same period as the disappearance of the megafauna, which is fascinating.”
“There’s also the possibility that this was witnessed by early inhabitants who arrived in the area. It would have been quite a spectacle.
The research has been published in the journal Geology.