() — When a NASA spacecraft intentionally crashed into an asteroid on September 26, the collision caused the space rock to release a comet-like tail.
A number of telescopes, including the Hubble Space Telescope, were perfectly positioned to capture the DART mission, or Double Asteroid Redirection Testand its consequences, which continues to amaze astronomers five months later.
The Hubble “film” It links images taken during a period that began more than an hour before the collision and ended on October 8. in the clip, released by NASA on Wednesday, debris can be seen moving away from the asteroid. The spinning, pinwheel-like features become visible once the asteroid’s orbit distorts the original conical shape of the debris.
The DART spacecraft, weighing approximately 544 kilograms, crashed head-on into the Dimorphos asteroid at 20,921 km/h, in an attempt to change the speed of the space rock.
It was the first time humanity tried to change the motion of a celestial object, and the results show how this kinetic impact technology could be used to deflect asteroids that may appear to be on a collision course with Earth. Neither Dimorphos nor the largest orbiting asteroid called Didymos pose a threat to Earth.
The DART impact was successful: changed the orbital period of Dimorphos around Didymos in 33 minutes, according to one of five new studies published Wednesday in the journal Nature that describe the consequences of the event.
The Hubble Space Telescope recorded debris shooting into space and eventually forming a tail behind the asteroid. (Credit: NASA)
“An active asteroid”: Dimorphos after impact
The Hubble clip reveals how the collision turned Dimorphos into an “active asteroid,” a space rock that orbits like an asteroid but has a tail of material like a comet, according to NASA.
The initial impact, which destroyed the DART spacecraft, spewed more than 1,000 tons of dust and rock from the asteroid and sent it hurtling into space. Debris was thrown from the cone-shaped asteroid, which was twisted by the asteroid’s orbit as it circled Didymos.
The debris then formed a comet-like tail that flowed behind Dimorphos. Unexpectedly, the tail broke in two just a few weeks after impact.
“The DART impact occurred in a binary asteroid system. We have never before witnessed the collision of an object with an asteroid in a binary asteroid system in real time, and it is truly amazing. I think it’s fantastic. There’s too much going on here. It will take some time to find out,” said Jian-Yang Li of the Institute for Planetary Sciences in Tucson, Arizona, and lead author of one of the the new studies of Natureit’s a statement.
The DART probe took an image of Dimorphos’s surface three seconds before impact. The squares represent the footprint where DART hit the asteroid. Large boulders, including one about 6.5 meters, were near the impact site. (Credit: NASA/Johns Hopkins APL)
“This is really unique to this particular incident,” Li said. “When I first saw these images, I couldn’t believe these features. I thought maybe the image was smudged or something.”
DART and the future of planetary defense
One of the contributing factors to DART’s success was the recoil generated when material was shot from the asteroid into space. The spacecraft impact alone would not have generated the momentum change Dimorphos experienced, according to the researchers.
“To serve as a proof of concept for the planetary defense kinetic impactor technique, DART needed to demonstrate that an asteroid could be attacked during a high-velocity encounter and that the target’s orbit could be changed. DART has successfully accomplished both,” the authors wrote in the study.
SETI Institute researchers and citizen scientists involved with the Unistellar network of telescopes also observed the DART impact and watched as the binary asteroid system it was suddenly brightening by a factor of 10. The observers published their results in an article in the journal Nature on Wednesday.
The body of the DART spacecraft collided between two large rocks while its two solar arrays impacted those rocks, as shown in this rendering. (NASA/Johns Hopkins APL)
Although the asteroid threat to Earth is currently unknown, new studies in the journal Nature show that missions like DART are capable of protecting our planet from space rocks.
“I was delighted when DART slammed into the asteroid for the world’s first demonstration of planetary defense technology, and that was just the beginning,” Nicola Fox, associate administrator for NASA’s Science Mission Directorate, said in a statement.
“These findings add to our fundamental understanding of asteroids and lay the foundation for how humanity can defend Earth from a potentially dangerous asteroid by altering its course.”
