When the DART spacecraft slammed into asteroid Dimorphos on September 26, 2022, telescopes worldwide (and in space) were watching as it happened. But others continued watching for numerous days afterward to observe the cloud of debris. DART’s (Double Asteroid Redirection Test) intentional impact was not only a test of planetary defense against an asteroid hitting our planet, but it also allowed astronomers the chance to study Dimorphos, a tiny moon or companion to asteroid Didymos.
New images released by the European Southern Observatory’s Very Large Telescope (VLT) show how the surface of the asteroid changed immediately after the impact when pristine materials from the interior of the asteroid were exposed. Other data tracked the debris’ evolution over a month, and provided details on how the debris changed over time. Additionally, astronomers searched for evidence of DART’s fuel but couldn’t find any.
Asteroid Didymos is spitting rocks out into space.
Last fall, when NASA’s DART mission impacted Didymos’ moon Dimorphos in a dramatic (and successful) attempt to change the object’s orbit, DART got a quick look at the Didymos system before the probe was purposefully smashed to pieces.
Alongside demonstrating the capability to prevent future asteroid strikes on Earth, DART also gathered new information about the dynamics of the pair of asteroids. The data collected suggests that Didymos is actively throwing material out into space, and there are likely millions of other small asteroids doing the same across the Solar System, all the time.
On September 26th, NASA’s Double Asteroid Redirection Test (DART) spacecraft collided with Dimorphos, the small moonlet that orbits the larger Near-Earth Asteroid (NEA) Didymos. The purpose was to test a planetary defense technique known as the kinetic impact method, where a spacecraft intentionally collides with a Potentially Hazardous Asteroid (PHAs) to alter its course. Based on a post-collision analysis, NASA determined that DART’s impact altered Dimorphos’ orbital period by 33 minutes and caused tons of rock to be ejected from its surface.
Since the collision, NASA has also been monitoring the cloud of ejecta produced by the impact to see how it has since evolved. The purpose of this is to better understand what the DART spacecraft achieved at the impact site, how much of it was delivered by the spacecraft, and how much was due to the recoil produced by the ejection. On December 15th, during the Fall Meeting of the American Geophysical Union (AGU) in Chicago, members of the DART team provided the preliminary analysis of their findings.
A worldwide team of dedicated observers ‘stood in the shadow’ of asteroid Didymos recently, as it passed in front of a distant star.
Amateur astronomers continue to provide key scientific observations, even in the modern era. This was highlighted recently, when a team of dedicated observers caught a series of occultation of a distant stars involving asteroid 65803 Didymos.
NASA says its DART spacecraft caused a larger-than-expected change in the path of its target asteroid when they collided two weeks ago — marking a significant milestone in the effort to protect our planet from killer space rocks.
Before the crash, DART’s science team said they expected the collision to reduce the time it took for Dimorphos to go around Didymos by about 10 minutes. NASA would have regarded any change in excess of 73 seconds as a success.
After the crash, detailed observations from ground-based observatories showed that the orbit was actually 32 minutes shorter — going from 11 hours and 55 minutes to 11 hours and 23 minutes. That’s three times as much of a change as scientists were expecting. Scientists also said Dimorphos appears to be slightly closer to Didymos.
“This is a watershed moment for planetary defense, and a watershed moment for humanity,” NASA Administrator Bill Nelson said today. “All of us have a responsibility to protect our home planet. After all, it’s the only one we have.”
More images and details keep coming in about the asteroid intentionally smashed by NASA’s Double Asteroid Redirection Test (DART) spacecraft last week, and this latest image is stunning.
A telescope in Chile called SOAR took an image of the asteroid Dimorphos two days after the impact by DART and found the asteroid is trailing a stream of debris more than 10,000 kilometers (6,000 miles) long. However, other reports indicate that the debris trail could now be as long as 50,000 km (31,000 miles), and could still be growing.
Here’s a sharper view of Dimorphos, the small asteroid moonlet that the DART (Double Asteroid Redirection Test) spacecraft intentionally crashed into. Eydeet on Imgur created a higher resolution image of Dimorphos by stacking the last few images received from the spacecraft before impact.
First impressions? It’s an egg-shaped rubble pile.
On September 26th, at 23:14 UTC (07:14 PM EST; 04:14 PM PST), NASA’s Double Asteroid Redirect Test (DART) spacecraft successfully struck the 160-meter (525 ft) moonlet Dimorphos that orbits the larger Didymos asteroid. The event was live-streamed all around the world and showed footage from DART’s Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) as it rapidly approached Dimorphos. In the last few seconds, DART was close enough that individual boulders could be seen on the moonlet’s surface.
About 38 seconds after impact, the time it took the signal to reach Earth, the live stream ended, signaling that DART had successfully impacted Dimorphos and was destroyed in the process. Meanwhile, teams of astronomers stretching from the Indian Ocean to the Arabian Peninsula watched the impact with their telescopes. One, in particular – the Les Makes Observatory on the island of Le Reunion in the Indian Ocean – captured multiple images of the impact. These were used to create a real-time video and show the asteroid brightening as it was pushed away, followed by material ejected from the surface.
Here’s one of the best videos we’ve seen of the last minutes of the Double Asteroid Redirection Test (DART) mission as it headed towards and slammed into the asteroid Dimorphos. This stabilized version of the last five-and-a-half minutes of images leading up to DART’s intentional collision with the asteroid was produced from NASA’s DART images. It was produced by the YouTube channel Spei’s Space News from Germany.