The famous Hubble Space Telescope tracked dramatic hour-by-hour changes in deep space caused by a NASA probe’s deliberate asteroid crash.
NASA’s Double Asteroid Redirection Test (DART) mission slammed into a small space rock called Dimorphos in late September 2022, aiming to test-drive a technique to divert an asteroid on a collision course with Earth. (There are no imminent asteroid threats to our planets, but practice makes perfect.)
Fresh images from the Hubble Space Telescope released today (March 1) show dust and debris flying at high speed away from Dimorphos and its larger asteroid companion, Didymos, after DART’s impact. The collision is believed to have thrown around 1,000 tons of old asteroid material into space.
Related: See the first images of DART’s wild asteroid crash!
“We’ve never seen an object collide with an asteroid in a binary asteroid system before in real time, and it’s really surprising. I think it’s amazing. There’s too much going on here. It’s going to take some time to figure out,” Jian -Yang Li at the Planetary Science Institute in Tucson, Arizona, said in a statement (opens in a new tab) published by the Space Telescope Science Institute (STScI) in Baltimore, which runs the Hubble science program.
The fresh pictures were accompanied by a study (opens in a new tab)led by Li in collaboration with 63 other DART team members, Wednesday (March 1) in the journal Nature (opens in a new tab). The paper is one of five published in Nature Wednesday, which together provide a detailed overview of the DART effect and its aftermath.
Information based on Hubble’s work indicates at least three stages of Dimorphos debris evolution. First, an ejecta cone formed, then the debris rolled into the asteroid’s orbit, and finally the tail moved behind the asteroid due to the pressure of the solar wind, the stream of charged particles that flowed constantly from our Sun.
The newly released Hubble movie begins with footage from about 1.3 hours after the impact, showing Dimorphos and Didymos at such a distance that the two space rocks cannot be resolved individually. About 2 hours after the event, debris can be seen moving at speeds over 4 mph (6.4 kmph) per hour, fast enough to overcome the gravitational pull of the asteroid system.
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The cone shape began to form about 17 hours after the impact. “The most prominent structures are rotating, pinwheel-shaped features. The pinwheel is associated with the gravitational pull of the companion asteroid Didymos,” STScI officials wrote in the statement.
Then, the final stage shows debris sweeping behind the asteroid, “where the lightest particles travel the fastest and farthest from the asteroid,” STScI officials added. But the processes have not yet been understood, as Hubble saw the tail split into two streams for a few days and the mechanism by which it happened is not clear.
Numerous instruments on Earth and in space imaged the DART impact, and more results will come from these various surveys as the data is analyzed, understood and processed.
Elizabeth Howell is the co-author of “Why am I taller? (opens in a new tab)?” (ECW Press, 2022; with Canadian astronaut Dave Williams), a book about space medicine. Follow her on Twitter @howellspace (opens in a new tab). Follow us on Twitter @Spacedotcom (opens in a new tab) or Facebook (opens in a new tab).