Oldest Material on Earth (7 Billion Years) Found Inside Meteorite

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  via SciTech Daily

  Fifty years ago, a 220 lb meteorite fell onto Murchison, Australia. Since then, the meteorite (called the Murchison meteorite) has been divided up between researchers, each hoping to find something unique inside it. And a team of researchers from the University of Chicago have done just that: the team found the oldest material on Earth inside the meteorite. 

  Stars are made up of dust and gas that have floated through space and accumulated together, collapsing in on each other and heating up to burn for millions of years before they die. When stars die, the particles that created them are sent back into space to float around and eventually form new stars. 

  The Murchison meteorite contains minerals that formed before our Sun was born. These minerals - called presolar grains - are bits of stardust that become trapped inside meteorites, where they remain unchanged for millions or billions of years. Presolar grains are only found in 5% of meteorites that fall to Earth, and they're also extremely tiny. Luckily, the Murchison meteorite contains an unusual amount of presolar grains, which were extracted from the meteorite thirty years ago. 

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  via SciTech Daily

  The researchers used age exposure data, which measures the presolar grains' exposure to cosmic rays (high energy particles that penetrate solid matter and fly through the solar system). Through this test, the team learnt that these presolar grains are the oldest ever materials discovered by humans. 

  Most of the grains are 4.6 to 4.9 billion years old (Earth is 4.5 billion years old), but some are around 5.5 billion - and the scientists are guessing that most of the young grains are actually composed of stars that formed before the beginning of our Solar System, and are around 7 billion years old. 

  The discovery has opened a debate about whether stars form at a steady rate, or whether there are highs and lows in the number of new stars that form over time. The team also found that presolar grains clump together like granola, which was previously thought impossible. 

  It's quite a day for science. 

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