A massive meteorite fell onto the continent of Australia around half a century ago. As we all know, meteorites are formed by clumps of space debris flying through space, making them a sort of time capsule of the universe. The meteorite that hit earth was different because, nestled inside the heart of the meteorite was a clump of stardust that has been revealed to be 7 billion years old, making it the oldest material on the planet.
"This is one of the most exciting studies I've worked on," says Philipp Heck, a curator at the Field Museum, associate professor at the University of Chicago, and lead author of a paper describing the findings in the Proceedings of the National Academy of Sciences. "These are the oldest solid materials ever found, and they tell us about how stars formed in our galaxy."
These kinds of discoveries are hard to come by, because the material is often so small and buried deep in the folds of the meteorite, but the Murchison meteorite, which fell in Australia in 1969, has been a treasure trove of stardust.
"It starts with crushing fragments of the meteorite down into a powder ," explains Jennika Greer, a graduate student at the Field Museum and the University of Chicago and co-author of the study. "Once all the pieces are segregated, it's a kind of paste, and it has a pungent characteristic-it smells like rotten peanut butter."
The researchers learned that some of the presolar grains in their sample were the oldest ever discovered-based on how many cosmic rays they'd soaked up, most of the grains had to be 4.6 to 4.9 billion years old, and some grains were even older than 5.5 billion years. For context, our Sun is 4.6 billion years old, and Earth is 4.5 billion.
Pretty neat, huh?