Scientists are eager to get their hands on these images as they admit we know very little about the potentially threatening space rocks Earth. Shipments to asteroids they are full of surprises. Almost two years before September 26th ARROW collision, NASA learned firsthand how unpredictable these space rocks can be when the The OSIRIS-REx mission briefly crashed into the asteroid Bennu for sample collection. Against all expectations, the scattered surface of the 0.3-mile-wide (0.5 km) asteroid was so soft that it nearly swallowed the probe, sending shivers down the spines of the spacecraft’s controllers and a massive wall of debris in space. With DART (short for “Double Asteroid Redirection Test”), NASA sent a spacecraft to change the orbit of an asteroid that scientists know as little about as they did about Bennu before OSIRIS-RExmeeting of “DART will be our first mission to study a binary asteroid system up close,” Terik Daly, associate instrument scientist on DART’s Didymos Reconnaissance and Asteroid Camera for Optical Navigation (DRACO) and planetary scientist at the Johns Hopkins Applied Physics Laboratory. who manages the DART mission for NASA, told Space.com.
The sixth space rock ever seen in detail
DART is targeting the 520-foot-wide (160-meter) asteroid Dimorphos, which orbits a larger 2,560-foot-wide (780-meter) asteroid called Gemini. From ground-based measurements, scientists know the speed at which Dimorphos orbits Gemini and have a rough idea of the chemical composition of the larger asteroid. Dimorphos, the final target of DART, however, is completely unknown. “Dimorphos is small enough that it hasn’t actually been studied separately from Gemini in great detail,” Daly said. “We know it’s a distinct body, but we know very little about the shape. We don’t know if Dimorph is elongated or spherical, we don’t know if it’s a single rock or a pile of boulders.” Thanks to the DART mission, Dimorphos will become one of the best-studied asteroids in the world universejoins the asteroid target OSIRIS-REx DetermineThe Itokawa and Ryugu asteroids visited by Japanese missions Hayabusa 1 and Hayabusa 2 and Eros asteroid, which was explored by NASA’s NEAR Shoemaker probe in the early 2000s. Dimorphos and Gemini will become only the sixth and seventh space rocks ever seen up close by a spacecraft, and it is among the most 26,000 asteroids currently known to regularly approach Earth’s orbit. In addition to the four above, the asteroid Tutati visited briefly by the Chinese Change 2 lunar probe, which took several pictures of it in 2012.
The Gemini/Dimorpho pair is the first binary asteroid to be visited by man-made spacecraft. (Image: ESA – Science Office)
Unforeseen collision results
Before DART slams into Dimorphos’ surface at a staggering 13,680 mph (22,015 km/h), the spacecraft will transmit images of the asteroid, captured by the DRACO camera, at a rate of one per second. First, the camera will see both asteroids, then it will focus on Dimorphos, guiding the DART towards it. As DART races toward the smaller space rock, the views will become increasingly detailed until the transmission stops abruptly— at the moment of impact. An Italian cubesat called LICIACubewhich traveled as a passenger on DART but was released 11 days before impact, will observe the impact from a safe distance of 600 miles (1,000 km) and then zoom to the newly marked surface to explore the impact in detail. Because scientists know so little about Dimorphos, they have no idea how the rock will respond to DART’s attack. Will the asteroid be as soft as Bennu and swallow the DART like a swamp, or will it be a solid chunk of rock that will completely flatten the van-sized DART? Asteroids are so small as well gravity so weak that even looking at the rock from above does not help predict the effect of the impact. “Images can be deceiving, and unless you touch [the asteroid]you don’t know,” suggested Patrick Michel, the European Space Agency’s (ESA) principal investigator. Hera’s missionwhich will visit Dimorpho and Gemini in 2027 to complete the investigation of the consequences of the impact, he said at an ESA press conference on 15 September. “The reason is that you are in a very low-gravity environment,” added Michel, a planetary scientist at the University of Côte d’Azur in France. we experience on Earth”.
(Image: ESA-Science Office)
What is Dimorpho made of?
Based on the way Gemini, the larger of the two rocks, reflects light, astronomers believe the asteroid is mostly made of silicate-rich rocks, unlike Bennu, which is made of less dense carbon-rich material. If Dimorphos is made of the same material as its larger friend, and the assumptions are correct, then the collision with DART will be less messy and probably less effective at changing Dimorphos’ orbit than it would be if the asteroid was softer, Daly said. To know for sure, however, we’ll have to wait for the LICIACube data. The cubesat will also make a flyby of Dimorphos and view the entire asteroid to allow scientists to reconstruct its shape. However, it will take weeks to months to download all the data and uncover the secrets of Dimorphos.
How do binary asteroids form?
Since the Gemini-Dimorphos pair is the first binary asteroid to be studied in detail, scientists hope to learn something about how these pairs of space rocks form, Daly said. According to estimates, about 16% of near-Earth asteroids wider than 650 feet (200 meters) may be binary. Even asteroid triplets are known to exist. According to some theories, such asteroid families may form when a larger rock starts spinning too fast, shedding some of its material in the process, Daly said. Other theories suggest that binaries and triplets may be produced in collisions.
“And one of the things we’ll be able to do with the DART mission is see what Gemini looks like in images and what Dimorphos looks like in images,” Daly said. “And if they’re similar — if their brightness is very similar, if they have similar kinds of morphology — that would suggest that maybe Gemini and Dimorph have split up somehow. Bennu but Dimorphos looks like a single rock in space, so maybe this division approach doesn’t make sense.”
Asteroids are full of surprises, and seeing one doesn’t mean we can predict the behavior of all the others. But learning as much as we can about Gemini and Dimorphos will help scientists make better guesses about other asteroids, Daly said. And the more we know, the better chance we have of making things right when a dangerous space rock sets its sights on Earth.
Follow Tereza Pultarova on Twitter @Tereza Pultarova. Follow us on Twitter @Spacedotcom and up Facebook.
