A small sample of asteroid collected by Japan’s Hayabusa-2 probe streaks back to Earth in 2020. Researchers now say the sample contains tiny grains of dust from other stars.
MORGAN SETTE/AFP via Getty Images
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MORGAN SETTE/AFP via Getty Images
A small sample of asteroid collected by Japan’s Hayabusa-2 probe streaks back to Earth in 2020. Researchers now say the sample contains tiny grains of dust from other stars.
MORGAN SETTE/AFP via Getty Images
Scientists have made a surprising discovery in a sample returned from an asteroid: Embedded in its rocks are grains of stardust.
The dust, which came from distant stars and drifted through space for millions or billions of years, could provide clues about how the solar system formed, according to Ann Nguyen, a cosmochemist at NASA’s Johnson Space Center in Houston, Texas.
“It was definitely not something I expected to find,” she says. “I cannot tell you the excitement I felt.”
Stellar Forges
Stars forged nearly all of the elements of the Universe. Many of the atoms that make up our bodies were themselves made inside of the core of a star somewhere else. That’s because the high pressures and temperatures can fuse lightweight atomic nuclei into heavier elements.
“The core is extremely hot, and then you go out in the atmosphere, it’s cool enough so that gas can form and aggregate into tiny grains,” Nguyen says.
Think of these little grains as cosmic dust motes. Sometimes the star that formed these grains would explode, blowing them across the galaxy like dandelion seeds. Other times they would drift away on their own — traveling on the stellar wind into deep space.
Ryugu is a near-Earth asteroid. Researchers think it picked up the stardust when it was previously residing at the edge of the solar system, possibly in a collision with another comet or asteroid.
JAXA/ISAS
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JAXA/ISAS
