A surprising new study is claiming that the Earth’s atmosphere was actually loaded with oxygen billions of years ago, totally contradicting what scientists had believed for many years.
The discovery is based on incredibly old micro-meteorites dated back 2.7 billion years ago, and scientists think they’ve found evidence in these microscopic particles that show that Earth wasn’t devoid of oxygen in its early days, according to a Monash University statement.
The scientists based their finding on 60 meteorites fossilized in limestone in Western Australia that were first uncovered in 2014 and 2015. The micro-meteorites are tiny — smaller than the width of a human hair — but they contain some mighty important information for understanding the early days of the Earth.
The scientists examined the chemical composition of the meteorites, which are fairly common and easy to find, and determined what the atmosphere was like back when these meteorites collided with the earth by studying the chemicals in them. They were able to do this because the makeup of the atmosphere would have affected how these chemicals cooled and what molecules they formed.
They found that rather than being mostly made up of nitrogen, the Earth’s upper atmosphere was packed with life-giving oxygen.
“Using cutting-edge microscopes we found that most of the micrometeorites had once been particles of metallic iron – common in meteorites – that had been turned into iron oxide minerals in the upper atmosphere, indicating higher concentrations of oxygen than expected,” team leader Dr. Andrew Tomkins said in the statement. “This was an exciting result because it is the first time anyone has found a way to sample the chemistry of the ancient Earth’s upper atmosphere.”