Scientists just discovered the Earth’s oldest material: 7 billion-year-old stardust preserved in a large, hard meteorite that impacted our planet half a century ago.
Stars have lives. They form when particles of dust and gas traveling through space collide, collapsing and heating up. They blaze for millions to billions of years before dying. When stars die, they release the particles generated in their winds into space, where they ultimately create new stars, as well as new planets, moons, and meteorites. And scientists have uncovered stardust that formed 5 to 7 billion years ago in a meteorite that crashed in Australia fifty years ago – the oldest solid substance ever detected on Earth.
This discovery adds fuel to a dispute among scientists over whether new stars originate at a constant pace or if the number of new stars varies over time. “Some believe that the galaxy’s star production rate is constant,” Heck explains. “However, owing to these grains, scientists now have direct evidence from meteorites indicating a time of heightened star formation in our galaxy seven billion years ago. This is a critical conclusion from our investigation.”
Heck stresses that this is not the first surprise discovery made by his team. As a side note to the primary study issues, the researchers discovered that presolar grains often drift through space locked together in enormous clusters, “like granola,” adds Heck. “No one imagined this would be feasible on that scale.”
Heck observes that there are still a lifetime’s worth of unanswered issues on presolar grains and the early Solar System. “I wish there were more people working on it to have a better understanding of our own galaxy, the Milky Way,” he adds.
The Field Museum, the University of Chicago, the Lawrence Livermore National Laboratory, Washington University, Harvard Medical School, ETH Zurich, and the Australian National University all contributed to this work. The Field Museum’s Science and Scholarship Funding Committee received funding from NASA, the TAWANI Foundation, the National Science Foundation, the Department of Energy, the Swiss National Science Foundation, the Brazilian National Council for Scientific and Technological Development, and the Swiss National Science Foundation.