In September 2022, NASA’s Double Asteroid Redirection Test successfully demonstrated how a fast-moving spacecraft could change an asteroid’s trajectory by crashing into it, potentially providing a way to defend Earth—though the asteroid in this test was never a real threat. A followup study suggests that debris from the 525-foot (160-meter) Dimorphos could actually strike back, though we’re not in any danger. The team posits that the collision produced a field of rocky ejecta that could reach Earth within 10 years. The research is currently hosted on the preprint server arXiv and is set to publish in The Planetary Science Journal.
The DART mission was so important because it showed that humankind actually does have a way to defend itself from the existential threat of incoming space rocks, like the one that ended the dinosaurs’ primacy on Earth some 66 million years ago. The DART team was a winner of the 2023 Gizmodo Science Fair for this superlative accomplishment in planetary defense.
In their recent study, scientists studied data collected by the Light Italian CubeSat for Imaging of Asteroids, or LICIACube, which observed DART’s impact of Dimorphos up close. Then, they fed LICIACube’s data into supercomputers at NASA’s Navigation and Ancillary Information Facility (NAIF) to simulate how the debris from the asteroid—basically dust and rock—may have disseminated into space. The simulations tracked about 3 million particles kicked up by the impact, some of which are large enough to produce meteors that could be spotted on Earth.
Particles from the impact could get to Mars in seven to 13 years, and the fastest particles could make it to our own world in just seven years. “This detailed data will aid in the identification of DART-created meteors, enabling researchers to accurately analyze and interpret impact-related phenomena,” the team wrote in the paper.
About 40 space boulders were visible in the vicinity of Dimorphos shortly after DART impacted the asteroid nearly two years ago. The mission altered Dimorphos’ position by tens of meters, indicating that a similar approach could be taken to mitigate the harm of future potentially hazardous asteroids. Though no asteroid currently threatens life on Earth (that we know of), it’s a real-enough threat that space agencies regularly run simulations of worst-case scenarios. But as the recent study shows, just deflecting the asteroid may be half the battle. Like a stale muffin, you can bat it away… but crumbs still get everywhere.
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