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This is an illustration of the collision of giant asteroids in the space that produced the dust that led to an ice age on Earth.
Don Davis, Southwestern Research Institute
The evolution of life on Earth sometimes depends on astronomical events. We know of the case of dinosaurs, which were wiped out by an asteroid or 10-kilometer comet hitting the Yucatán peninsula in Mexico about 66 million years ago.
However, scientists have just discovered that an important glacial period, several million years ago, was triggered by an asteroid collision in the solar system.
Could this unexpected discovery help fight global warming? & Nbsp;
In the newspaper "Extraterrestrial Trigger for Middle Ordovician Glaciation: Dusts from L-Chondrite Parent Body Dissolution"Published in Science Advances, researchers at the Chicago Field Museum, Lund University in Sweden and others, claim that the breakup of a major asteroid there 466 million years ago. years filled the entire interior solar system with a huge amount of dust leading to ice age. & nbsp;
What was the size of the asteroid?
The calculations put the asteroid into question about 150 km wide. However, instead of hitting the Earth, this asteroid simply broke in the asteroid belt between Mars and Jupiter and created much more dust than usual in the internal solar system. This is the largest documented break in the last three billion years, and its break still provides nearly one-third of the meteorites that fall on Earth today, according to the newspaper.
This diagram shows a flying bird view of our asteroid belt, located between the orbits of Mars (red) and Jupiter (violet).
NASA / JPL-Caltech
What is space dust?
The Earth still has space dust in its atmosphere, as well as dust from volcanoes, deserts and sea salt. In the current stratosphere, alien dust represents 1% of all dust and has no impact on climate. "Normally, Earth earns about 40,000 tons of extraterrestrial material each year," says Philipp Heck, curator at the Field Museum, associate professor at the University of Chicago, and one of the authors of the paper. "Our hypothesis is that the large amount of extraterrestrial dust over a period of at least two million years has played an important role in changing the Earth's climate, thus contributing to cooling," said Heck.
How did the dust of space cool the climate of the Earth? & Nbsp;
Essentially by blocking the sunlight. It was already known that the climate of the Earth had cooled down 466 million years ago, but the outbreak and intensification of the conditions of the "Ordovician pack ice" have so far been a mystery. Basically, the effect of blocking dust partially prevented sunlight from reaching the Earth and an ice age began. "It's like standing in the middle of your living room and breaking a vacuum bag, but on a much larger scale," says Birger Schmitz, professor of geology at Lund University and head of the university. # 39; study. "Our results show for the first time that such dust has sometimes cooled the Earth dramatically."
How space dust stimulated biodiversity on Earth & nbsp;
The arrival of all this space dust has occurred so gradually – in fact, over a period of at least two million years – that life has been able to survive. adapt to changes in temperature, causing an explosion of new species. This is what is called theGreat Ordovician Biodiversification Event".
It is a 466 million year old fossil meteorite created during the same collision of asteroids that caused the dust that led to an ice age. At the top of the photo is the fossil of a creature resembling a squid, called nautiloid.
Field Museum, John Weinstein
How did researchers understand this? & Nbsp;
They searched for traces of space dust in rocks 466 million years old and compared them to tiny micrometeorites of Antarctica. "We studied extraterrestrial matter, meteorites and micrometeorites, in the sedimentary record of the Earth, that is, rocks that were once seabed," says Heck about the Study of petrified sediments from the seabed in Kinnekulle, southern Sweden. "And then we extracted the extraterrestrial material to find out what it was and where it came from." Extracting extraterrestrial matter was a tedious process, as old rocks had to be acid treated to gnaw them and leave the "space material" for chemical analysis. They found helium atoms devoid of neutron, a sure sign of an exit from the Sun, as well as rare metals often found in asteroids. & Nbsp;
In short, the dust of the asteroid is enriched in helium after being bombarded by the solar wind en route to the Earth. "This result was completely unexpected," says Schmitz. "It's only when we had the latest helium measurements that everything fell into place."
These are cliffs made of sedimentary rock that was once an ancient seabed. The gray horizontal line in the rock indicates where the dust of the collision between asteroids has fallen.
Field Museum, Philipp Heck
How could it help fight against global warming? & Nbsp;
"We are talking about time scales of millions of years," says Heck. "It is very different from the climate change caused by the meteorite that killed the dinosaurs 65 million years ago, and it is different from the global warming of today. boost. " & Nbsp;
However, the unexpected discovery may be relevant to combat global warming if carbon dioxide emissions are not reduced. Could we therefore reproduce the dust cloud that triggered global cooling 466 million years ago? It may be possible to place asteroids in orbits around the Earth in such a way that they permanently remove dust and partially prevent sunlight from reaching the Earth. Heck thinks such a ploy would be very risky. "Geo-engineering proposals need to be evaluated very critically and very carefully, because if something goes wrong, things could get worse than before," he says. However, this knowledge could be useful. "We are facing global warming, it's undeniable, and we need to think about how to prevent or minimize catastrophic consequences," he said. "Any reasonable idea must be explored." & Nbsp;
"Our results show for the first time that such dust has sometimes cooled the Earth dramatically," says Schmitz. "Our studies can provide a more detailed and empirical understanding of how this works, which can then be used to assess whether the simulations are realistic. "& nbsp;
Wishing you a clear sky and big eyes.
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This is an illustration of the collision of giant asteroids in the space that produced the dust that led to an ice age on Earth.
Don Davis, Southwestern Research Institute
The evolution of life on Earth sometimes depends on astronomical events. We know of the case of dinosaurs, which were wiped out by an asteroid or 10-kilometer comet hitting the Yucatán peninsula in Mexico about 66 million years ago.
However, scientists have just discovered that an important glacial period, several million years ago, was triggered by an asteroid collision in the solar system.
Could this unexpected discovery help fight global warming?
In the study "An extraterrestrial trigger for the Middle Ordovician Ice Age: dust from the dissolution of the parent body of L-chondrite" published in Science Advances, Field Museum researchers from Chicago, from Lund University in Sweden, argue that the breakup of a major asteroid 466 million years ago flooded the inner solar system with huge amounts of dust that caused a ice Age.
What was the size of the asteroid?
The calculations put the asteroid into question about 150 km wide. However, instead of hitting the Earth, this asteroid simply broke in the asteroid belt between Mars and Jupiter and created much more dust than usual in the internal solar system. This is the largest documented break in the last three billion years, and its break still provides nearly one-third of the meteorites that fall on Earth today, according to the newspaper.
This diagram shows a flying bird view of our asteroid belt, located between the orbits of Mars (red) and Jupiter (violet).
NASA / JPL-Caltech
What is space dust?
The Earth still has space dust in its atmosphere, as well as dust from volcanoes, deserts and sea salt. In the current stratosphere, alien dust represents 1% of all dust and has no impact on climate. "Normally, Earth earns about 40,000 tons of extraterrestrial material each year," says Philipp Heck, curator at the Field Museum, associate professor at the University of Chicago, and one of the authors of the paper. "Our hypothesis is that the large amount of extraterrestrial dust over a period of at least two million years has played an important role in changing the Earth's climate, thus contributing to cooling," said Heck.
How did the dust of space cool the climate of the Earth?
Essentially by blocking the sunlight. It was already known that the climate of the Earth had cooled down 466 million years ago, but the outbreak and intensification of the conditions of the "Ordovician pack ice" have so far been a mystery. Basically, the effect of blocking dust partially prevented sunlight from reaching the Earth and an ice age began. "It's like standing in the middle of your living room and breaking a vacuum bag, but on a much larger scale," says Birger Schmitz, professor of geology at Lund University and head of the university. # 39; study. "Our results show for the first time that such dust has sometimes cooled the Earth dramatically."
How space dust stimulated biodiversity on Earth
The arrival of all this space dust has occurred so gradually – in fact, over a period of at least two million years – that life has been able to survive. adapt to changes in temperature, causing an explosion of new species. This is what is called the "Great Ordovician Biodiversity Event".
It is a 466 million year old fossil meteorite created during the same collision of asteroids that caused the dust that led to an ice age. At the top of the photo is the fossil of a creature resembling a squid, called nautiloid.
Field Museum, John Weinstein
How did researchers understand this?
They searched for traces of space dust in rocks 466 million years old and compared them to tiny micrometeorites of Antarctica. "We studied extraterrestrial matter, meteorites and micrometeorites, in the sedimentary record of the Earth, that is, rocks that were once seabed," says Heck about the Study of petrified sediments from the seabed in Kinnekulle, southern Sweden. "And then we extracted the extraterrestrial material to find out what it was and where it came from." Extracting extraterrestrial matter was a tedious process, as old rocks had to be acid treated to gnaw them and leave the "space material" for chemical analysis. They found helium atoms devoid of neutron – a sure sign of being drawn from the Sun – as well as rare metals often found in asteroids.
In short, the dust of the asteroid is enriched in helium after being bombarded by the solar wind en route to the Earth. "This result was completely unexpected," says Schmitz. "It's only when we had the latest helium measurements that everything fell into place."
These are cliffs made of sedimentary rock that was once an ancient seabed. The gray horizontal line in the rock indicates where the dust of the collision between asteroids has fallen.
Field Museum, Philipp Heck
How could it help fight against global warming?
"We are talking about time scales of millions of years," says Heck. "It is very different from the climate change caused by the meteorite that killed the dinosaurs 65 million years ago, and it is different from the global warming of today – this global cooling was a sweet boost. "
However, the unexpected discovery may be relevant to combat global warming if carbon dioxide emissions are not reduced. Could we therefore reproduce the dust cloud that triggered global cooling 466 million years ago? It may be possible to place asteroids in orbits around the Earth in such a way that they permanently remove dust and partially prevent sunlight from reaching the Earth. Heck thinks such a ploy would be very risky. "Geo-engineering proposals need to be evaluated very critically and very carefully, because if something goes wrong, things could get worse than before," he says. However, this knowledge could be useful. "We are facing global warming, it's undeniable, and we need to think about how to prevent or minimize catastrophic consequences," he said. "Any reasonable idea should be explored."
"Our results show for the first time that such dust has sometimes cooled the Earth dramatically," says Schmitz. "Our studies can provide a more detailed and empirical understanding of how this works, which can then be used to assess whether the simulations are realistic. "
Wishing you a clear sky and big eyes.