Space

NASA's asteroid-smashing space debris spotted by Hubble telescope

The Hubble Space Telescope has snapped the results of smashing a spacecraft into the asteroid Dimorphous

20 July 2023

This Hubble Space Telescope image of the asteroid Dimorphos was taken on December 19, 2022, nearly four months after the asteroid was impacted by NASA?s DART mission (Double Asteroid Redirection Test). Hubble?s sensitivity reveals a few dozen boulders knocked off the asteroid by the force of the collision. These are among the faintest objects Hubble has ever photographed inside the solar system. The free-flung boulders range in size from three feet to 22 feet across, based on Hubble photometry. They are drifting away from the asteroid at a little more than a half-mile per hour. The discovery yields invaluable insights into the behavior of a small asteroid when it is hit by a projectile for the purpose of altering its trajectory. — The asteroid Dimorphous, three months after it was hit by a spacecraft
NASA, ESA, David Jewitt (UCLA), and Alyssa Pagan (STScI)

Last year, NASA smashed a spacecraft into the asteroid Dimorphos. Now, the Hubble Space Telescope has captured the resulting debris in stunning detail, revealing a glittering field of boulders.

The Double Asteroid Redirection Test (DART) saw a 600-kilogram spacecraft impact Dimorphos, which circles a larger asteroid called Didymos, to see if it could alter the space rock’s orbit as a practice run for diverting future dangerous asteroids. The mission was a success, reducing the length of Dimorphos’s orbit by about 33 minutes following impact in September 2022.

A few months later, in December 2022, David Jewitt at the University of California, Los Angeles and his colleagues used the Hubble Space Telescope to learn more about the debris expelled by the collision. They found 37 large boulders, ranging in size from 1 to almost 7 metres across, seen as small sparkles of light in the picture above.

It is likely the rocks were loosely tied to Dimorphous’ surface, rather than shards from the body of the asteroid itself. They are also moving slowly relative to Dimorphous – at around 0.8 kilometres per hour – and their total mass is around 0.1 per cent of their parent asteroid.

Space Week: A seven-day tour of the cosmos

To celebrate the launch of our new podcast, Dead Planets Society, New Scientist editors have selected some of our most delightful premium articles about the solar system and beyond

“This tells us for the first time what happens when you hit an asteroid and see material coming out up to the largest sizes,” Jewitt said in a statement. “The boulders are some of the faintest things ever imaged inside our solar system.”

Voyage across the galaxy and beyond with our space newsletter every month.

This cloud of boulders will be studied further by the European Space Agency’s Hera spacecraft, which is scheduled to leave Earth in October 2024 and arrive at Didymos and Dimorphos at the end of 2026. By using the Hubble observations taken now and future Hera observations, astronomers might be able to pin down the boulders’ exact trajectories.

Topics: