In September 2022, NASA deliberately crashed its DART spacecraft into a small asteroid some 6.8 million miles from Earth, in an attempt to redirect its trajectory as a test-run for any future rock that might threaten Earth.
Now, the Hubble Space Telescope has compiled imagery taken of the target rock, Dimorphos, before and after the September crash test. The images have been stitched together to create a timelapse movie of the Double Asteroid Redirection Test (DART) mission.
Ground telescopes picked up grainy footage of the violent event, but Hubble also captured the hour-or-so before the event and the days after.
The timelapse starts at 1.3 hours before the DART spacecraft’s impact into Dimorphos, according to a European Space Agency release. The first image taken after the impact is around 20 minutes after the event; if you look carefully, you will see lines of dust and debris kicked up by the impact.
About 17 hours after the impact, the ejected debris changes shape due to interactions between Dimorphos and its larger partner asteroid, Didymos. The gravitational pull of Didymos yanks the debris toward it, causing the ejecta to take on a pinwheel pattern.
But the pinwheel doesn’t last. As time passes, the lightest particles of debris fly the farthest from the asteroid, and the debris field becomes more diffuse. At a greater distance (around the 16-second mark in the video) the debris tails split in two.
Shortly after the September test, NASA scientists determined that Dimorphos’ orbit had indeed been changed by about 32 minutes, proving that humankind can redirect the trajectory of bodies in space.
The DART team is a winner of the 2023 Gizmodo Science Fair, for its successful effort in changing Dimorphos’ trajectory. The experiment, which wasn’t guaranteed to work, provides the first steps toward a viable strategy for planetary defence.