Scientists discover Earth's oldest material — stardust

S c i e n t i s t s h a v e d i s - covered the oldest solid material ever f ound on Earth f rom a meteorite that fell in Australia about 50 years ago.

The material that the researchers examined are called presolar grains – or stardust – particles from a star that can eventually form new stars, along with planets, moons and meteorites.

This particular sample is about 5 billion to 7 billion years old and predates the sun, which the Field Museum in Chicago says is about 4.6 billion years old.

“T h i s i s o n e o f t h e m o s t e x c i t i n g s t u d - i e s I ' v e w o r k e d o n , ” said Philipp Heck, l ead a u t h o r o f t h e s t u d y publi s hed i n t he peerreviewed Proceedings of the National Academy of Sciences and associate professor at the University of Chicago.

The stardust was preserved in a meteorite that fell in Murchison, Victoria, i n 1969. Researchers at the University of Chicago have been studying the mat e r i a l f o r a b o u t 3 0 years.

P r e s o l a r g r a i n s a r e extremely rare and were found in only about 5% of meteorites that have fallen to Earth, according to the Field Museum. They are formed when a star dies a nd c a n t e l l s c i e nt i s t s more about the history of stars.

“It's the next best thing t o bei ng abl e t o t ake a s ample di r ectl y f r om a star,” said Jennika Greer, a graduate student at the Fi e l d Museum a nd t he University of Chicago and co-author of the study.

From e xamining t hi s material, scientists were able to deduce that there w a s a “b a b y b o o m ” period of stars forming about 7 billion years ago. The finding contradicts a highly contested debate between experts i n t he field.

“Some people think that the star formation rate of the galaxy is constant,” Heck said. “But thanks to these grains, we now have direct evidence for a period of enhanced star formation in our galaxy 7 billion years ago with samples from meteorites.”