Hubble observes a cluster of boulders around impacted asteroid Dimorphos

By Georgina Torbet July 22, 2023

Last year, NASA deliberately crashed a spacecraft into an asteroid, in a first-of-its-kind test of planetary defense. At the time, telescopes around the world including the Hubble Space Telescope observed the impact between the DART spacecraft and the Dimorphos asteroid, capturing footage of the plumes of dust thrown up. Now, Hubble has observed Dimorphos once again and seen that a number of boulders have been ejected from the asteroid.

The Hubble image shown below was taken on 19 December 2022, around four months after the impact, and shows the bright streak of the asteroid across the sky, surrounded by small boulders which were knocked loose during the impact. This view was only possible after several months as the impact initially sent up large amounts of dust which made it difficult to see the asteroid in detail.

A NASA/ESA Hubble Space Telescope image of the asteroid Dimorphos taken on 19 December 2022. — This NASA/ESA Hubble Space Telescope image of the asteroid Dimorphos was taken on 19 December 2022, nearly four months after the asteroid was impacted by NASA’s DART (Double Asteroid Redirection Test) mission. 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 ejected boulders range in size from 1 metre to 6.7 metres across, based on Hubble photometry. They are drifting away from the asteroid at around a kilometre per hour. The discovery yields invaluable insights into the behaviour of a small asteroid when it is hit by a projectile for the purpose of altering its trajectory. NASA, ESA, D. Jewitt (UCLA)

Researchers observed 37 boulders in total, ranging in size from 1 to 6.7 meters. The aim of the impact was not to destroy the asteroid but to redirect it — the idea being that, in case an asteroid were threatening Earth, this method could be effective at nudging its orbit so that it would miss the planet. The recent observations also gave further confirmation that the asteroid’s trajectory around its partner asteroid, Didymos. However, to learn more about the exact effects of the impact, we will have to wait for the European Space Agency’s Hera mission, which will visit the asteroid binary to collect more data and which will launch next year.

In total, around 0.1% of the mass of the Dimorphos asteroid was displaced by the impact, with the boulders now drifting away from the asteroid. Hubble scientists explain that these are probably not made from chunks of the asteroid, but rather are boulders that were sitting on the asteroid’s surface when the impact occurred.

“It’s not clear how the boulders were lifted off the asteroid’s surface,” Hubble scientists write. “They could be part of an ejecta plume that was photographed by Hubble and other observatories. Or a seismic wave from the impact may have rattled through the asteroid — like hitting a bell with a hammer — shaking loose the surface rubble.”

Editors' Recommendations

Topics

Tech News

Georgina Torbet

Space Writer

Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…

Space

Hubble spies baby stars being born amid chaos of interacting galaxies

Galaxy AM 1054-325 has been distorted into an S-shape from a normal pancake-like spiral shape by the gravitational pull of a neighboring galaxy, seen in this Hubble Space Telescope image. A consequence of this is that newborn clusters of stars form along a stretched-out tidal tail for thousands of light-years, resembling a string of pearls. They form when knots of gas gravitationally collapse to create about 1 million newborn stars per cluster.

When two galaxies collide, the results can be destructive, with one of the galaxies ending up ripped apart, but it can also be constructive too. In the swirling masses of gas and dust pulled around by the gravitational forces of interacting galaxies, there can be bursts of star formation, creating new generations of stars. The Hubble Space Telescope recently captured one such hotbed of star formation in galaxy AM 1054-325, which has been distorted into an unusual shape due to the gravitational tugging of a nearby galaxy.

Galaxy AM 1054-325 has been distorted into an S-shape from a normal pancake-like spiral shape by the gravitational pull of a neighboring galaxy, as seen in this Hubble Space Telescope image. A consequence of this is that newborn clusters of stars form along a stretched-out tidal tail for thousands of light-years, resembling a string of pearls. NASA, ESA, STScI, Jayanne English (University of Manitoba)

Space

Small exoplanet could be hot and steamy according to Hubble

This is an artist’s conception of the exoplanet GJ 9827d, the smallest exoplanet where water vapour has been detected in its atmosphere. The planet could be an example of potential planets with water-rich atmospheres elsewhere in our galaxy. It is a rocky world, only about twice Earth’s diameter. It orbits the red dwarf star GJ 9827. Two inner planets in the system are on the left. The background stars are plotted as they would be seen to the unaided eye looking back toward our Sun, which itself is too faint to be seen. The blue star at upper right is Regulus, the yellow star at bottom centre is Denebola, and the blue star at bottom right is Spica. The constellation Leo is on the left, and Virgo is on the right. Both constellations are distorted from our Earth-bound view from 97 light-years away.

One of the big topics in exoplanet research right now is not just finding exoplanets but also looking at their atmospheres. Tools like the James Webb Space Telescope are designed to allow researchers to look at the light coming from distant stars and see how it is filtered as it passes by exoplanets, allowing them to learn about the composition of their atmospheres. But scientists are also using older telescopes like the Hubble Space Telescope for similar research -- and Hubble recently identified water vapor in an exoplanet atmosphere.

“This would be the first time that we can directly show through an atmospheric detection that these planets with water-rich atmospheres can actually exist around other stars,” said researcher Björn Benneke of the Université de Montréal in a statement. “This is an important step toward determining the prevalence and diversity of atmospheres on rocky planets."

Space

NASA automated system predicts asteroid impact over Germany

This map shows the location where the small asteroid 2024 BX1 harmlessly impacted Earth’s atmosphere over Germany, about 37 miles (60 kilometers) west of Berlin, on Jan. 21. A NASA system called Scout predicted the impact time and site within 1 second and about 330 feet (100 meters).

Earth is frequently bombarded by small asteroids, which burn up harmlessly in the atmosphere. However, identifying and tracking these asteroids is an important step in protecting the Earth against the threat of larger and potentially more dangerous impacts. NASA recently predicted the impact of a small asteroid that struck Germany using its impact prediction system, Scout.

"A small asteroid about 3 feet (1 meter) in size disintegrated harmlessly over Germany on Sunday, Jan. 21, at 1:32 a.m. local time (CET)," NASA wrote in an update. "At 95 minutes before it impacted Earth’s atmosphere, NASA’s Scout impact hazard assessment system, which monitors data on potential asteroid discoveries, gave advance warning as to where and when the asteroid would impact. This is the eighth time in history that a small Earth-bound asteroid has been detected while still in space, before entering and disintegrating in our atmosphere."