Last year NASA tested out a new method for defending the planet from incoming objects by crashing a spacecraft into an asteroid. Recently, further analysis of data from the impact has shown more about what occurred during and after the impact, and how effective it was at changing the orbit of the asteroid.
The Hubble Space Telescope captured a series of images showing the aftermath of the impact, which have been put together into a video showing the bright flash of the impact and the emerging plume of material sent up from the asteroid:
The data from Hubble is also shown in the form of three images. The first shows the scene around two hours after impact, with a cone of material called ejecta made up of around 1,000 tons of dust. The second image from 17 hours after impact shows how this cone of material interacts with the gravity of the other asteroid in the pair, called Didymos. Finally, the third image shows how the ejecta is pulled into a tail shape due to the effects of sunlight.
This view shows how the effects of the impact on the asteroid are dependent on it being a part of a binary system: two asteroids orbiting each other. “The DART impact happened in a binary asteroid system,” said lead author of a study on the ejecta, Jian-Yang Li of the Planetary Science Institute, in a statement. “We’ve never witnessed an object collide with an asteroid in a binary asteroid system before in real time, and it’s really surprising. I think it’s fantastic. Too much stuff is going on here. It’s going to take some time to figure out.”
More analysis of the data from the impact has been reported by NASA. The agency shared in an update that the impact altered the orbit of Dimorphos by 33 minutes, showing that this method can be effective at changing an asteroid’s trajectory. That means that if such an asteroid were ever to threaten Earth, we’d have an idea of how to deflect it — as long as it was spotted in time as several years of preparation are required, and provided it was on a similar scale of size to Dimorphos, which is around half a mile across.
“I cheered when DART slammed head-on into the asteroid for the world’s first planetary defense technology demonstration, and that was just the start,” said Nicola Fox, associate administrator for NASA’s Science Mission Directorate, in the update. “These findings add to our fundamental understanding of asteroids and build a foundation for how humanity can defend Earth from a potentially hazardous asteroid by altering its course.”
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