Astronomers are "excited" because this celestial collision has obtained a large amount of data.
Italian probe licicacube swept over the asteroid Didymos (bottom) and Dimorphos (top)
Telescopes on space and Earth captured the spectacular scene after NASA DART spacecraft hit the asteroid Dimorphos on September 26. Thomas Zurbuchen, NASA's deputy director for science, said the impact was "the first human experiment to deflect celestial bodies" and "a huge success."
"We're all excited," said Andy Rivkin, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, who was involved in the mission.
The small Italian spacecraft LICIACube flying with DART filmed the impact 11 million kilometers away from the earth. On September 27, The Italian Space Agency released the first image of licicacube, showing that after DART hit the double guard, a huge fireworks-like plume emerged from the double guard. The rocks and other debris expanded rapidly, like a huge smog of smoke.
ATLAS Observatory observed that DART collided with Dimorphos while crossing the sky with companion Didymos. Image source: University of Hawaii ATLAS project
, head of the licicacube scientific team of the National Institute of Astrophysics, Rome, said at a press conference that studying the evolution of plume will help reveal the physical properties of the double-shaped guard. By analyzing how plumes form and disperse, researchers can calculate how much kinetic energy of the DART is used to eject debris from the "double-shaped guard" and how much is possible to change the orbit of the asteroid - the goal of the mission.
The spacecraft itself has been completed. "A lot of it was shattered, and some were melted," said Megan Brooke Hill, a physicist at Lawrence Livermore National Laboratory in California. "It's hard to say, but I don't think it will leave a big part behind."
LICIACube, Italy's first deep space mission, uses an autonomous navigation technology that locks the camera on a "double guard" that is only 55 kilometers away from the asteroid when it flies quickly after the DART impact. It used two cameras—a black and white camera called LEIA and a tri-color camera called LUKE—to take pictures of the double-shaped dragon before and after the crash. The picture shows dramatic brightness during the impact, and then in the following minutes, smoke plume continues to expand and drift outward. The complex structures in the fragmented plume — almost "spider-like" in some places — will help modelers understand exactly how the impact unfolds, Bruck Syal said. There are still more than 600 images on
licacube, waiting to be downloaded to Earth in the next few weeks.
"A lot of rocks"
golf cart sized DART hit the target of the size of the Great Pyramid at 7:14 pm. ET. Only over 3 hours later, the first images of licicacube arrived at the control center in Turin, Italy.
Despite the large amount of jet debris, "Double Fors" remains basically intact. The ground telescope confirmed this by capturing other photos of the impact, which showed that the plume expanded outward as the rest of the asteroid galloped forward. The double-shaped dragon is currently mainly visible in the southern hemisphere, so these initial observations came from telescopes in the Indian Ocean, including Réunion Island and South Africa. Dozens of telescopes continue to monitor it to determine if its orbit has changed.
DART spacecraft flew over Didymos and approached Dimorphos to impact
Astronomers take days to weeks to confirm whether DART has accomplished its main goal, which is to speed up Dimorphos orbit around its partner asteroid Didymos for 10 minutes or more. Neither asteroid poses a threat to the earth, but the purpose of the test is to see if dangerous space rocks are found flying towards the earth in the future, whether humans can really change the orbit of the asteroid.
Dimorphos was never observed up close before the disaster rescue team arrived. As the spacecraft got closer, it discovered that the asteroid was in the shape of an egg.DART took a series of images during the descent, revealing that the double-shaped dragon was also covered with boulders. "It's obviously a pile of gravel," Rifkin said. "Just a lot of messy stones."
Read the original text: https://www.nature.com/articles/d41586-022-03066-z
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