Scanning electron microscope image of one of the clumps of presolar grains, or stardust. Image via Janaína N. Ávila/EurekAlert!
Ancient stardust in meteorite is older than Earth
Grains of stardust – particles left behind by star explosions – in an Australian meteorite are now the oldest known material on Earth. A new study suggests this stardust came to be long before our sun ever existed.
As the saying goes, we are all made of stardust. It’s true. The elements in our bodies – oxygen, carbon, nitrogen, calcium and so on – are made in the thermonuclear furnaces of stars. When scientists speak of stardust, or cosmic dust, they’re speaking of the leftover tiny particles from dead stars that exploded as supernovae. This stardust later goes into forming new stars, planets and moons, including those in our own solar system. It goes into the solar system’s debris, the asteroids and comets, and ultimately meteorites, or rocks from space that find their way to Earth’s surface. Now scientists at the Field Museum in Chicago have found the oldest known samples of stardust in a meteorite that landed in Australia. The meteorite is estimated to be 5 to 7 billion years old. The stardust samples are the oldest material ever discovered on Earth. This dust is even older than our solar system.
The new peer-reviewed study was published in Proceedings of the National Academy of Sciences on January 13, 2020.
credits: SPACE – Paul Scott Anderson, Proceedings of the National Academy of Science, Earth Sky, Chicago Field Museum, Phillip Heck