Tag Archives: Atacama Desert

Ancient Comet May Have Turned Chilean Desert Into Glass

Clods of glass in the Atacama Desert, site of an ancient fireball airburst.
Photo: R. Scott Harris

Nearly 50 miles (80 kilometers) of the Chilean coast are covered with oblong fragments of desert glass that researchers who recently studied them say came from a comet’s explosion over the Atacama Desert about 12,000 years ago.

The explosion was what’s called an airburst, which can happen when an object like a meteor or comet falls to Earth. These objects heat up due to friction with our planet’s atmosphere. While some burn up entirely in the atmosphere, other objects explode when they come in contact with thicker parts of the atmosphere. They can cause ground temperatures to be as hot as the Sun, with beyond-hurricane-force winds.

Such was the case for a comet that fell to Earth during the late Pleistocene, according to the team of researchers who studied the composition of the silicate glasses littered about Chile’s Atacama. They found the fireball’s explosion caused bits of space rock to fuse with the molten soils below, forming glasses. Their results were published this week in Geology.

“The Atacama is perfect for preserving the record,” Peter Schultz, a planetary geologist at Brown University, told Gizmodo in an email. “The difference between other glasses across the Atacama and these glasses is that our glasses are really large and indicate complex interactions between the airburst, heating, and winds.

“In other words, it teaches us about the details of the event for the first time,” Schultz added. “We actually have more glasses in Argentina of much older ages but can show that these were produced by actual collisions.”

Previously, a different team thought that the glasses came from ancient grass fires, long before the area became desert, that burned hot enough to transform the soil. But the recent team suspects an extraterrestrial object is the source of the geological oddity because of the unique mineral constitution and structure of the glasses, which showed evidence of being bent and transformed while still liquid. Those details have been observed in other airburst remnants and wouldn’t look so violent in grassfire glasses.

Furthermore, the team found minerals that come from other space rocks, like troilite and cubanite. Such inclusions are similar to those collected by NASA during the Stardust mission, from dust of 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 release. “To have the same mineralogy we saw in the Stardust samples entrained in these glasses is really powerful evidence that what we’re seeing is the result of a cometary airburst.”

The current age estimate of the airburst remains a work in progress on the testing front. The youngest date estimate, made by another co-author, was about 11,500 years ago. “There’s also a chance that this was actually witnessed by early inhabitants, who had just arrived in the region,” Schultz said in the same release. “It would have been quite a show.”

If not for humans, depending on the timing, one has to pity the doomed giant ground sloths and other megafauna in the area. They would’ve been burned to a crisp in an instant.

More: Here’s What Would Happen If a Giant Asteroid Struck the Ocean

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Signs of Water Seen in Massive Galaxy of the Early Universe

Scientists studying the most massive known galaxy in the early universe have found evidence of water in it, an intriguing observation that sheds light on how the universe has evolved.

This massive galaxy is actually a pair of galaxies, which are known together as SPT0311-58. First discovered in 2017, the galactic duo is seen as they were when the universe was a mere 780 million years old (it’s now encroaching on its 14 billionth birthday). Finding water there makes it the most distant detection of the stuff in a regular star-forming galaxy. The team’s research was accepted for publication in The Astrophysical Journal.

“This galaxy is the most massive galaxy currently known at high redshift, or the time when the Universe was still very young,” said Sreevani Jarugula, an astronomer at the University of Illinois and a co-author of the recent paper, in a National Radio Astronomy Observatory press release. “It has more gas and dust compared to other galaxies in the early Universe, which gives us plenty of potential opportunities to observe abundant molecules and to better understand how these life-creating elements impacted the development of the early Universe.”

It may look like a couple magenta smudges, but that distant galaxy is essentially a repository of information about the universe shortly after the Big Bang. SPT0311-58 was found by researchers using the Atacama Large Millimeter/submillimeter Array, or ALMA, one of the best telescope arrays around for looking at the beginnings of the universe.

ALMA is located high in Chile’s Atacama Desert, giving it terrifically sharp and unpolluted views of the night sky. The array also drove the recent finding, which comes from a study of the galaxy’s gas content. Besides water molecules, the researchers also found carbon monoxide.

Part of the ALMA telescope in Chile’s Atacama Desert.
Photo: MARTIN BERNETTI/AFP (Getty Images)

“This exciting result, which shows the power of ALMA, adds to a growing collection of observations of the early Universe,” said Joe Pesce, an astrophysicist and ALMA Program Director at the National Science Foundation, in the same release. “These molecules, important to life on Earth, are forming as soon as they can, and their observation is giving us insight into the fundamental processes of a Universe very much different from today’s.”

Things were pretty energetic earlier in the universe, so young galaxies (meaning the most ancient ones we see today) produced stars at a much greater rate than our own galaxy does now. Looking at the types of gases and dusts in those galaxies and their relative proportions can help astronomers answer questions about the rate of star formation and how galaxies like SPT0311-58 interact with one another and the interstellar medium.

ALMA has a terrific habit of imaging these faraway smudges and discerning the minutiae that make them up, thereby helping astronomers better understand the beginning of everything and, maybe, what gave rise to us. Here’s to ALMA and all the discoveries it’s still to make.

More: Scientists Are Turning Earth Into a Telescope to See a Black Hole

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Very Large Telescope Images 42 of the Biggest Asteroids in Our Solar System

Though not as massive or colorful as planets, asteroids have a lot to teach us about our local corner of the universe. That’s especially the case for asteroids close enough to be sampled—such as Bennu was in October 2020—or when rocky fragments fall to Earth as meteorites.

Asteroids are the detritus left over from the creation of our solar system’s planets, and as such, they contain information about what things were like billions of years ago. NASA has counted over 1 million asteroids to date, and recently, the Very Large Telescope at the European Southern Observatory imaged 42 of the largest ones.

“Only three large main belt asteroids, Ceres, Vesta and Lutetia, have been imaged with a high level of detail so far, as they were visited by the space missions Dawn and Rosetta of NASA and the European Space Agency, respectively,” said Pierre Vernazza from the Laboratoire d’Astrophysique de Marseille in France in an ESO press release. Vernazza led a study on the asteroids published today in Astronomy & Astrophysics.

The Very Large Telescope makes observations in visible and ultraviolet light. It is actually made up of four unit telescopes, all of which sit high up in Chile’s Atacama Desert, one of the best places for looking at the sky. The images were taken using the SPHERE instrument on the telescope, which ordinarily does direct imaging of exoplanets, but in this case was able to get a great look at a number of asteroids in the main belt.

The recent work by Vernazza’s team improves the quality and quantity of images detailing asteroids’ sizes and structures. These images will help astronomers get better understanding of the solar system’s origin.

The asteroids range from the very dense ones, like Kalliope and Psyche, to some of the least dense, like Sylvia and Lamberta. The smallest two asteroids in this group are Ausonia and Urania, which each measure about 55 miles wide. The largest asteroid, Ceres, is 584 miles across, large enough that it is considered a dwarf planet.

All of these objects offer insights about the primordial soup that forged them; for example, the research team found that the least dense asteroids of the 42 most likely formed farther out than their denser brethren, somewhere beyond the orbit of Neptune, and eventually migrated inward to their current locations.

“Our observations provide strong support for substantial migration of these bodies since their formation. In short, such tremendous variety in their composition can only be understood if the bodies originated across distinct regions in the Solar System,” said Josef Hanuš of the Charles University in Prague and one of the authors of the study, in the ESO release.

And if you’re impressed by the Very Large Telescope, just wait until the Extremely Large Telescope becomes operational later in the 2020s. That telescope will gather 20 times more light than a unit of the Very Large Telescope, allowing astronomers to see fainter objects better than they currently can. (Alas, the Overwhelmingly Large Telescope never made it past the concept phase.)

More: A Fight Over a Sacred Mountaintop Will Shape the Future of Astronomy

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Jurassic-Era ‘Winged Lizard’ Unearthed In Chile

Dinosaur: The fossils have now been confirmed to be of a rhamphorhynchine pterosaur.

Santiago:

Chilean scientists have announced the discovery of the first-ever southern hemisphere remains of a type of Jurassic-era “winged lizard” known as a pterosaur.

Fossils of the dinosaur which lived some 160 million years ago in what is today the Atacama desert, were unearthed in 2009.

They have now been confirmed to be of a rhamphorhynchine pterosaur — the first such creature to be found in Gondwana, the prehistoric supercontinent that later formed the southern hemisphere landmasses.

Researcher Jhonatan Alarcon of the University of Chile said the creatures had a wingspan of up to two meters, a long tail, and pointed snout.

“We show that the distribution of animals in this group was wider than known to date,” he added.

The discovery was also “the oldest known pterosaur found in Chile,” the scientists reported in the scientific journal Acta Paleontologica Polonic. 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

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