When a NASA spacecraft successfully knocked down an asteroid last year it sent dozens of rocks skittering into space, images from the Hubble telescope showed Thursday.
NASA’s fridge-sized DART probe smashed into the pyramid-sized, rugby ball-shaped asteroid Dimorphos about 11 million kilometers (6.8 million miles) from Earth in September last year.
A spacecraft hits an asteroid in the first-ever test of Earth’s planetary defenses.
New images taken by the Hubble Space Telescope show that the collision also sent 37 rocks—ranging from one meter (three feet) to seven meters (22 feet) across—floating through space.
They represent about two percent of the rocks already scattered on the asteroid’s surface untouched, scientists estimate in a new study.
The finding suggests that possible future missions to divert life-threatening asteroids headed for Earth could also spray rocks in our direction.
But these particular rocks don’t pose any threat to Earth—in fact they hardly ever go anywhere.
They are moving away from Dimorphos at about one kilometer (half a mile) per hour—roughly the walking speed of a giant tortoise, Hubble said in a statement.
The boulders are moving so slowly that the European Space Agency’s Hera mission—which will arrive at the asteroid in late 2026 to assess the damage—may even be able to see them.
“The boulder cloud will still disperse when Hera arrives,” said David Jewitt, a planetary scientist at the University of California at Los Angeles and lead author of the new study.
“It’s like a very slow expansion of the bee colony,” he said.
Hubble’s “amazing observation” “tells us for the first time what happens when you hit an asteroid and see material ejected,” he added.
“Boulders are some of the most benign objects described within our solar system.”
A scattering of boulders shows that DART left a crater about 50 meters (160 feet) wide on Dimorphos, according to Jewitt. The entire asteroid is 170 meters across.
Scientists plan to continue tracking the boulders to determine their path and determine how exactly they launch to the surface.
The study was published in Astrophysical Journal Letters.
More information:
David Jewitt et al, The Dimorphos Boulder Swarm, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/ace1ec
© 2023 AFP
Citation: Asteroid-smashing NASA probe sends boulders into space (2023, July 23) retrieved on July 23, 2023 from https://phys.org/news/2023-07-asteroid-smashing-nasa-probe-boulders-space.html
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