Stardust Created 7 Billion Years Ago Is the Oldest Stuff on Earth
Between 5 and 7 billion years ago, a dying star shot an explosion of particles through space. Some of that stardust ended up in a meteorite that landed in Murchison, Australia, in 1969. And according to new research, it's officially the oldest known solid material on Earth.
For the new study, published in the journal Proceedings of the National Academy of Sciences 30 years after the research began, scientists pulverized fragments of the meteorite to determine its age. The resulting paste-like substance reportedly smelled like "rotten peanut butter." The strange aroma "comes from byproducts of the breakdown of the abiotic organic molecules—molecules that didn't form from life—in the Murchison meteorite," lead author Philipp R. Heck, a curator at Chicago's Field Museum, tells Mental Floss.
Heck used acid to further break down the rock and isolate the grains of stardust, which are smaller than the period at the end of this sentence. To date the particles, the team measured neon isotopes that formed when cosmic rays hit the solid matter making up the stardust. The older the stardust is, the more cosmic rays it has been exposed to, so the amount of neon isotopes it contains can be used to estimate its age. Heck compares the method to collecting water in a bucket to determine how long it's been raining.
The team found that the meteorite contained particles older than 5.5 billion years and possibly as old as 7 billion years. The Earth has only been around for 4.5 billion years, and the sun for 4.6 billion. The formation of this super-old stardust is believed to have occurred during an "astral baby boom," according to a statement released by the Field Museum, in which an uptick in stellar activity literally created the matter that shapes the world we know today.
When the grains formed, "most stars that we see tonight in the sky didn’t exist," Heck says. "The bright stars that would have been shining through our galaxy were the previous generation of stars, our parent stars. [They] formed the elements that later became fuel and ingredients for the solar system, Earth, and us. These stars formed the material that we are made out of."
While the grains in the Murchison meteorite are the oldest solid material on the planet, many of the gases on Earth are much older. Some of the hydrogen in your body, for example, may have originated with the Big Bang 13.7 billion years ago.