Didymos Archives

September 8, 2023September 12, 2023 by Nancy Atkinson

DART Had a Surprising Impact on its Target

This Hubble image shows debris from Didymos about one day after NASA's DART spacecraft slammed into it. Image Credit: NASA, ESA, STScI, J. Li (PSI)

After NASA’s DART mission slammed into asteroid Dimorphous in September 2022, scientists determined the impact caused tons of rock to be ejected from the small asteroid’s surface. But more importantly, DART’s impact altered Dimorphos’ orbital period, decreasing it by about 33 minutes.

However, a group of researchers measured the orbital period about a month later and discovered that it had increased to 34 minutes — 1 minute longer than the first measurements. Even though it was a single impact from DART, some force continued to slow the asteroid’s orbit, and astronomers don’t yet know what that mechanism might be.

July 20, 2023July 20, 2023 by Nancy Atkinson

DART Impact Ejected 37 Giant Boulders from Asteroid Dimorphos’ Surface

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. Credit: NASA, ESA, D. Jewitt (UCLA).

When the DART (Double Asteroid Redirection Test) spacecraft intentionally slammed into asteroid moonlet Dimorphos on September 26, 2022, telescopes around the world and those in space watched as it happened, and continued to monitor the aftermath.

Of course, the Hubble Space Telescope was focused on the event. In looking at Hubble’s images and data from post-impact, astronomers discovered 37 boulders that were ejected due to the impact. These boulders range in size from 1 meter (3 feet) to 6.7 meters (22 feet).

However, these boulders were not debris created by the spacecraft’s impact. Instead, they were boulders that were already on the surface of Dimorphos, and the impact event “shook” the boulders loose. A team of astronomers, led by David Jewitt and Yoonyoung Kim say in their paper detailing the findings that these boulders are some of the faintest objects ever imaged in the Solar System, only visible because of Hubble’s keen sensitivity. The images here showing the boulders surrounding Dimorphos were taken on December 19, 2022.

March 22, 2023March 22, 2023 by Nancy Atkinson

Another Look at the Aftermath of DART's Impact Into Dimorphos

This artist’s illustration shows the ejection of a cloud of debris after NASA’s DART spacecraft collided with the asteroid Dimorphos. Credit: ESO/M. Kornmesser

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.

March 15, 2023March 15, 2023 by Scott Alan Johnston

Didymos is Spinning So Quickly That Rocks are Detaching at its Equator and Going Into Orbit

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.

December 21, 2022December 22, 2022 by Matt Williams

What Kind of an Impact did DART Have on Dimorphos? The Science Results are Here

Tail — Two tails of dust ejected from the Didymos-Dimorphos asteroid system are seen in new images from the NASA/ESA Hubble Space Telescope, Credit: NASA/ESA

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.

October 26, 2022October 26, 2022 by David Dickinson

Occultation Chasers Nab the Shadow of Didymos, Post DART Impact

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.

September 29, 2022September 29, 2022 by Matt Williams

The First Telescope Images of DART's Impact are Starting to Arrive

Artist's impression of the DART mission impacting the moonlet Dimorphos. Credit: ESA

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.