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Discovery of the Oldest Known Asteroid

Scientists have discovered a 2.2 billion-year-old asteroid crater in Australia which could explain the end of an ice age.

Throughout Earth’s history, space rocks have consistently plummeted the planet. With each collision came a different impact to the Earth’s atmosphere. But on Jan. 21, 2020 scientists found the oldest crater known to man, which could have been the reason for a significant change to the Earth’s atmosphere.

According to the BBC, this asteroid impacted Yarrabubba, a city in Western Australia about 2.2 billion years ago. This would make the crater around half of the age of the Earth. The asteroid was discovered by scientists associated with the Curtin’s School of Earth and Planetary Sciences and NASA’s Johnson Space Center, and the research was published in a leading science peer-reviewed British journal called Nature Communications.

How the scientists in this study confirmed the age of this asteroid was through isotopic analysis of minerals. The main minerals used were zircon and monazite that were then shock recrystallized due to the strike of the asteroid. 

Courtesy: BBC

The scientists mention the impact crater could have impacted an ice-covered landscape, vaporizing large amounts of ice into the atmosphere.

According to Professor Kirkland from Curtin’s School of Planetary Sciences, this is a potential reason for the end of a deep freeze on Earth.

“Now we know the Yarrabubba crater was made right at the end of what’s commonly referred to as the early Snowball Earth — a time when the atmosphere and oceans were evolving and becoming more oxygenated and when rocks deposited on many continents recorded glacial conditions,” said Professor Kirkland to Science Daily.

Snowball Earth refers to the period in time in which the Earth was covered with ice sheets up to three miles thick. The Yarrabubba impact crater is said to have vaporized up to 11,000 trillion pounds of water vapor into the atmosphere, creating a greenhouse gas potentially changing the climate of the Earth.

Professor Kirkland also says, “The impact event itself might not have been the full reason for a global climate shift, but if we are in a dynamic period of Earth’s history when other things are happening this might have been the straw that broke the camel’s back.”

And according to co-author of the study, Aaron Cavosie, the crater had been hiding in plain sight for about 20 years. The reason for this delay was because it is impossible to see the crater with your eyes. This is due to billions of years of erosion. Instead of physically seeing the crater to find it, scientists used magnetic field mapping to find evidence.

Before the Yarabubba asteroid was discovered, the oldest known asteroid of the time was found in the Vredefort Dome of South Africa, and is 200 million years younger. With this new information, scientists are now starting to believe that there are older asteroids to be discovered. This could also give us a glimpse into more of the Earth’s history. And with technology on the rise, it is possible.

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I am an Environmental Science major passionate about implementing sustainability into everyone's lives.
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