Meteorites have been smacking into the Earth for a long time, even if they were once a real phenomena that people considered fake. Back on 11:00 AM in 1969, though, a particularly old meteorite came roaring over the town of Murchison, Australia, according to Smithsonian, scattering its pieces into hay bales and rooftops. Riding atop these meteorite fragments was ancient stardust, and in a 2020 study, scientists dated one of these grains as being approximately seven billion years old. That renders this little speck of cosmic debris as, in fact, the most ancient solid material on the entire planet. Groovy. 

Because the stardust found on this meteorite is older than the sun (literally), it is referred to as presolar grains. To properly date these things, the experts measured the impact of cosmic rays upon them (and yes, those are real things, not just a Marvel Comics buzzword). As Phillip Heck, the lead author of the study — and a curator at the Chicago’s Field Museum, where much of the Murchison meteorite’s remnants are located today — puts it, “Some of these cosmic rays interact with the matter and form new elements. And the longer they get exposed, the more those elements form. I compare this with putting out a bucket in a rainstorm. Assuming the rainfall is constant, the amount of water that accumulates in the bucket tells you how long it was exposed.”