An hour-by-hour movie of an asteroid that was deflected by a NASA spacecraft

When the Dart mission collided with the asteroid Dimorphos last September in the first-ever test of planetary defense, the Hubble Space Telescope was in the process of roaming. A great photo opportunity that gives astronomers a unique perspective on the event.

On September 26, a spacecraft weighing just over 500 kilograms collidedasteroidasteroid Dimorphos. The goal of the Dart mission (double asteroid redirection test) : Test our ability to modify an asteroid’s trajectory to gather data that can help researchers imagine a defense strategy for our Earth against a threatening asteroid. By colliding head-on into Dimorphos at about 21,000 km/h, Dart threw more than 1,000 tons of crushed rock into space.

The test was closely monitored by the Hubble Space Telescope. And today intervalinterval The images he recorded reveal, hour by hour, how this wreck and dust shredded. Invaluable and amazing information on a rather complex dispersion pattern. Because it was the first time he was there Astronomy scientistsAstronomy scientists Witness a collision at the heart of a twin asteroid system. “It will take some time to understand.”says Jian Yang Lee Planetary Science Institute Tucson (USA), in a NASA press release.

Tracked extruded

The movie opens a little over an hour before Impact. At the time, Hubble was unable to separate the two asteroids Didymos and Dimorphos that make up the system. The first post-collision photo with Dart was taken twenty minutes after impact. Debris is ejected from Dimorphos at a speed of 6.5 km/h. It is enough not to fall back on the asteroid. Bomber formation a conecone Hollow with long filiform filaments.

About seventeen hours after the impact, the debris pattern entered a second phase. dynamic interaction within binary systembinary system It begins to deform the output cone. The most important structures are the rotating elements in the form of a pinwheel. as a result of Didymus’ gravitational pull. “It’s really unique to this particular incidentLi’s comments. When I first saw these pictures, I couldn’t believe these features. I thought maybe the image is corrupted or something. »

Hubble then shows the debris being swept back into a tail similar to that of a cometcomet from here pressurepressure affiliate a lighta light the sunsun on small dust particles. It extends into a train of debris as the lighter particles move faster and farther from the asteroid. Then, Hubble recorded this tail splitting in two for a few days.

NASA’s Dart mission confirms that spacecraft colliding with asteroids can successfully derail them. © NASA

Dart mission success

If the researchers still plan to work on these images, they are already confirming the success of the Dart mission. Firstly, because it has proven that an asteroid less than a kilometer in diameter can be intercepted. Even without an advanced reconnaissance mission. Provided there is sufficient warning time. Preferably decades, all the same …

Then, because the Dart mission actually deflected Dimorphos’ orbit by about 33 minutes. Researchers have now discovered that this was not only thanks to the thrust from the collision between the spacecraft and the asteroid, but also to the projectile’s bounce. What next, principle validation ” I’collidercollider mobility » as a means of planetary defence.

But the mission goes beyond that. It provides scientists with a unique opportunity to study so-called asteroids “Osoul” An asteroid orbiting another. Such asteroids would be the result of collision events, precisely. The Dart mission thus made it possible to simulate and observe what would correspond to the formation process of an active asteroid for the first time.