NASA last month deliberately crashed a spacecraft (DART) into an asteroid (Dimorphos) as part of humanity’s first planetary defense test . Now, just over a week later, astronomers have revealed a new image of the aftermath of that collision, showing a 10,000 km long tail of dust and debris.
Follow-up observations show that the dust is being pushed away from the asteroid by the solar wind, creating a debris tail similar to the ones we’re used to seeing from comets. The collision took place on Monday, September 26, and in less than two days, a well-defined tail was easily visible from ground-based telescopes.
snapshots
Two days after the DART collision, astronomers Teddy Kareta and Matthew Knight have captured the large plume of dust and debris spewing from the asteroid’s surface with the SOAR telescope at NSF’s NOIRLab’s Cerro Tololo Inter-American Observatory, one of many observatories on Earth monitoring the impact.
“It’s impressive how clearly we were able to capture the structure and extent of the aftermath in the days after the impact,” said Teddy Kareta (Lowell Observatory).
“Now begins the next phase of work for the DART team analyzing the data and observations with the help of other observers around the world who were able to study this extraordinary event together,” added Matthew Knight of the US Naval Academy. “We plan to use SOAR to monitor material ejection in the coming weeks and months . The combination of SOAR and AEON is just what we need for efficient tracking of evolving events like this.”
Observations by many other astronomers will begin to paint a more detailed picture of the DART impact in the coming weeks, including how much material the asteroid ejected.
What will you get from images like this?
“These observations will allow us to gain insight into the nature of Dimorphos’s surface, how much material was ejected by the collision, how fast it was ejected, and the particle size distribution in the expanding dust cloud, for example if the impact it caused the little moon to shed large chunks of material or mostly fine dust,” the experts point out.
Although Dimorphos did not pose a threat to humanity (and, in fact, no known near-Earth object is currently considered a significant danger), there are many asteroids and other space rocks that we have not yet discovered or begun to track, for so the data fetched from DART could literally come in handy at any time. If an object ends up posing a serious impact threat to our planet, we already have a plan of action. DART is the first phase of that plan.
It was the world’s first test of a kinetic impact mitigation technique, using a spacecraft to deflect an asteroid, changing the object’s orbit.
“Analyzing this information will help us protect Earth and its inhabitants by better understanding the amount and nature of the ejection resulting from an impact, and how that might change an asteroid’s orbit,” the astronomers say.
Ground-based telescopes are currently analyzing the Dimorphos data to assess whether the mission managed to alter its orbit around its “twin” asteroid Didymos. Scientists believe the impact created a crater, hurled streams of rock and dirt into space and, most importantly, altered the asteroid’s orbit.
Reference: CTIO/NOIRLab/SOAR/NSF/AURA/T. Kareta, Lowell Observatory/M. Knight, US Naval Academy/TA Rector, University of Alaska Anchorage & NSF’s NOIRLab/M. Zamani & D. de Martin, NSF’s NOIRLab.
