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Distant asteroid collision gave terrestrial biodiversity Ancient impetus



About 466 million years ago, there was an asteroid collision in the asteroid belt between Mars and Jupiter. The collision caused the main asteroid to break, creating a shower of dust throughout the entire solar system. This event is called the Ordovician Meteorological Event and its dust caused an ice age here on Earth.

This glacial period contributed to a tremendous boost to the ancient Earth's biodiversity.

In recent decades, scientists have uncovered evidence showing how different events occur in space life on Earth. The most famous of these is the impact of Chicxulub, which ended the reign of dinosaurs about 66 million years ago. But there are other events in space that have affected life on Earth, including a supernova that erupted about 2.6 million years ago that could have destroyed large ocean animals, and another supernova that erupted about 41

,000 years ago, and that may have helped wipe out mammoths.

But in this case, the glacial asteroid asteroid era may have helped Earth's life rather than hindered it.

Scientists have known about the Ordovician Meteor event (OME) for some time. They know it's an L-chondrite asteroid because they can see its dusty debris in stratified layers on Earth. In fact, the break of those 150 km. An ancient asteroid diameter of 467 million years ago still supplies nearly one-third of all meteorites that hit Earth. This event was not banal; this is the largest asteroid breakdown we have known in the last 3 billion years.

Something else happened on Earth about 466 million years ago: the glacial period of the Middle Ordovician. The climate was homogeneous before, the same from pole to pole. But when the ice age came, the seas froze at the poles and the equatorial regions were much warmer than the polar. Different climatic regions have caused greater evolution of species and have led to a boom in biodiversity.

But the association of the Ordovician meteor event with the mid-Ordovician ice age is controversial.

"Our results show for the first time that such

Birger Schmidt, lead author, Lund University.

According to a new study entitled "The Extraterrestrial Trigger of the Ordovician Middle Ages: Dust from the Disintegration of the L-Chondrite-Parent Body", the causal link between OME and the Ice Age is much stronger. The study was published in the journal Science Advances.

The study's authors come from various institutions around the world, including the University of Lund in Sweden. Their work focuses on seabed sediment data from the Ordovician meteor event. The authors say that after OME there was an increase of three to four orders of fine-grained material falling to Earth.

  Birger Schmitz to the sediment at the seabed in Kinnekulle (Photo: Philip R. Heck)
Birger Schmitz to the sediment at the seabed in Kinnekulle (Photo: Philip R. Heck)

The amount of material falling to Earth had to coincides with the amount covering the inner solar system. "Extraordinary amounts of dust in the entire internal solar system during> 2 Ma after the collapse of the L-chondrites cooled the Earth and caused the conditions of the Ordovician ice houses, the fall at sea level and the high fauna turnover associated with the Great Ordovician Biodiversity Event," the document says.

"Typically, the Earth receives about 40,000 tons of alien material each year," says Philip Heck, a curator at the Field Museum, an associate professor at the University of Chicago and one of the authors of the article. "Imagine multiplying this by a factor of a thousand or ten thousand."

"Our hypothesis is that large amounts of extraterrestrial dust over at least two million years have played an important role in changing Earth's climate, contributing to cooling," Heck.

"Our results show for the first time that such dust has sometimes cooled the Earth dramatically," says Birger Schmidt of Lund University of Sweden, lead author of the study and research fellow at the Field Museum. "Our studies can provide a more detailed, empirically grounded understanding of how it works, and this in turn can be used to evaluate whether model simulations are realistic."

Scientists focused on 466 million annual sedimentary marine rocks from simultaneously with OME. They searched for traces of space dust and then compared it to small micrometeorites from Antarctica for comparison. "We studied alien matter, meteorites and micrometeorites in the sedimentary record of Earth, which means rocks that were once on the seabed," Heck says. "And then we took out the alien matter to find out what it was and where it came from."

This is an image of stratigraphic levels in ancient rocks on the seabed in southern Sweden, one of the places where the authors explored the rock. The red line marks the time of the meteor event in Ordovician. Along the same line, the scale analysis shows an abundance of L-chondritic grains that descended to Earth after OME. The character of the limestone also changes, indicating that it was formed at a lower sea level when the poles froze and the oceans fell. Image Credit: Birger Schmidt, Lund University

They used acid to eat the rock, leaving behind only the cosmic dust. Then they analyzed the chemical composition of the powder. They sought evidence of extraterrestrial origin in the form of He3, an isotope of helium that comes from the Sun but is absent on Earth. Finding these isotopes and other rare minerals that come from space, such as chromites, proves that the powder is of extraterrestrial origin.

The authors of this study are the first to show that the mid-Ordovician ice age is related to the Ordovician meteor event. "The weather looks perfect," he says. OME dust would block sunlight, causing global cooling and the ice age.

But this glacial period was not catastrophic for life on Earth. Exactly the opposite. All this dust has been deposited on Earth for two million years, which means that cooling is gradual, not catastrophic. As a result, life had a chance to adapt. This adaptation has led to a boom in new life forms, such as species adapted to the new climatic conditions. This boom is called the Great Ordovician Biodiversity of the Event (GOBE.)

Hell, it's quick to warn people not to make false conclusions. Just because this type of climate change has led to greater biodiversity does not mean that we can take climate change lightly.

"In the global cooling we've been studying, we've been talking for millions of years," Heck said. "This is very different from the climate change caused by the meteorite 65 million years ago that killed dinosaurs, and is different from global warming today – this global cooling was a slight push.

If this gradual cooling sounds like a solution we could apply to curb global climate change, Heck throws cold water on the idea as well. "Geoengineering proposals should be evaluated very critically and very carefully, because if something goes wrong, things can get worse than before."

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