NASA Probe Launches Boulders into Space After Colliding with Asteroid
Images from the Hubble telescope revealed that last year, a NASA spacecraft effectively altered the trajectory of an asteroid, causing numerous boulders to scatter into space.
NASA’s refrigerator-sized DART probe hit the pyramid-sized, rugby-ball-shaped asteroid Dimorphos about 11 million kilometers (6.8 million miles) from Earth in September of last year.
The spacecraft significantly knocked an asteroid off course in the first such test of Earth’s planetary defense.
New images taken by the Hubble Space Telescope show that the impact also sent 37 rocks ranging from one meter to seven meters (22 feet) into space.
They represent about two percent of the boulders that were already scattered on the surface of the loosely held together asteroid, researchers estimate in a new study.
The discovery suggests that potential future missions to deflect life-threatening asteroids heading toward Earth could also spray boulders in our direction.
But these particular rocks pose no threat to Earth – they’ve hardly disappeared anywhere.
They drift away from Dimorphos at about a kilometer (half a mile) per hour — roughly the same speed at which a giant tortoise walks, Hubble said in a statement.
The rocks are moving so slowly that the European Space Agency’s Hera mission – which is due to arrive at the asteroid in late 2026 to inspect the damage – will even be able to look at them.
“The boulder cloud is still spreading when Hera arrives,” said David Jewitt, a planetary scientist at the University of California, Los Angeles and lead author of the new study.
“It’s like a very slowly expanding swarm of bees,” he said.
Hubble’s “amazing observation” “tells us for the first time what happens when you hit an asteroid and see material coming out,” he added.
“Boulders are some of the faintest things ever imaged inside our solar system.”
The scattering of rocks shows that DART left a crater about 50 meters (160 feet) wide on Dimorphos, according to Jewit. The entire asteroid has a diameter of 170 meters.
Scientists plan to continue tracking the boulders to determine their trajectory and determine how precisely they left Earth.
The study was published in the Astrophysical Journal Letters.
