The asteroid struck Earth in Western Australia, leaving behind the 43.5-mile-wide (70km) Yarrabubba meteor crater. The impact occurred around the time of a warming period and the end of a planet-wide ice age.
Scientists now speculate the asteroid helped shape the planet’s climate shortly after oxygen first appeared in the atmosphere.
Thanks to NASA, Curtin University in Australia and Imperial College London in the UK, researchers have also found Yarrabubba is the oldest known impact crater on the planet.
The asteroid hit the planet when the Earth was only half-as old as it is today.
The crater’s formation places it right around the time the so-called “Snowball Earth” came to an end.
Professor Chris Kirkland from Curtin University said: “Yarrabubba, which sits between Sandstone and Meekatharra in central WA, had been recognised as an impact structure for many years, but its age wasn’t well determined.
- China news: World’s largest alien hunting telescope now up and running
“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.”
The Snowball Earth hypothesis speculates the planet’s surface was covered in ice sheets between one and three miles thick.
The new study offers some fascinating insight into how asteroid impacts can shape a planet’s habitability.
Until now, asteroid impacts such as the one near Mexico’s Yucatan Peninsula 66 million years ago, were known to bring death and destruction to the planet and its inhabitants.
But scientists are now excited by the “twist of fate” brought about by the Yarrabubba asteroid strike.
Timmons Erickson from NASA’s Johnson Space Center said: “The age of the Yarrabubba impact matches the demise of a series of ancient glaciations.
Snowball Earth ended at almost the same time as the Yarrabubba impact
Dr Thomas Davison, Imperial College London
“After the impact, glacial deposits are absent in the rock record for 400 million years.
“This twist of fate suggests that the large meteorite impact may have influenced global climate.”
Dr Thomas Davison of Imperial College London, who co-authored the study, added: “Snowball Earth ended at almost the same time as the Yarrabubba impact.
“Is this a coincidence, or could the Yarrabubba impact event be an unexpected cause of global climate change.”
North Pole will be difficult to recover after ice melts [INSIGHT]
Yellowstone volcano: Earthquakes not eruptions are the ‘greatest hazard’ [ANALYSIS]
Astronomer snaps a ‘potentially hazardous’ asteroid on approach [PICTURES]
- NASA news: Hubble spots galaxy from 200 million light-years away
“We also would like to know when the frequency of meteor impacts declined to the point where life could emerge and thrive.
“These are all big questions in the field of science.”
The scientists determined the Yarrabubba crater’s age by analysing a “melt sheet” of crystallised rock that formed in the impact.
Although the original impact crater measured 43.5 miles (70km) across, only a 12.4-mile-wide (20km) section remains hidden away in the Australian outback.
Due to wind and rain erosion, the crater is all but visible today but untouched samples of zircon and monazite minerals were still found in Yarrabubba.
The minerals are crystals of lead and uranium than can be dated under an electron microscope.
Dr Aaron Cavosie from Curtin University said: “Our findings highlight that acquiring precise ages of known craters is important – this one sat in plain sight for nearly two decades before its significance was realised.
“Yarrabubba is about half the age of the Earth and it raises the question of whether all older impact craters have been eroded or if they are still out there waiting to be discovered.”
The asteroid study was published in the journal Nature Communications.
Source: Read Full Article