UNITED STATES: NASA has revealed that 101955 Bennu, an asteroid discovered back in 1999, has a surface that can be compared to a play area for kids, complete with loosely packed particles that make up the entire exterior of the asteroid.
The most recent discoveries regarding the surface of Bennu were made public on July 7 in two publications written by Walsh and Dante Lauretta, the chief investigator of OSIRIS-REx, based at the University of Arizona, Tucson.
Scientists have discovered something astonishing after studying data from NASA’s OSIRIS-REx spacecraft’s sample collection from the asteroid Bennu in October 2020: the spacecraft would have sunk into Bennu if it had not fired its thrusters to back away as soon as it grabbed rock and dust from the asteroid’s surface.
Bennu’s shell is made up of particles that are so loosely packed and barely adhered to one another that if a human were to step onto it, they would experience very little resistance, similar to stepping into a pit of plastic balls, which are common play locations for children.
In San Antonio-based Southwest Research Institute’s opinion, Kevin Walsh, a member of the OSIRIS-REx science team said, “If Bennu was totally packed, it would imply almost solid rock, but we found a lot of vacuum region in the surface.”
Due to Bennu’s continually unpredictable behaviour during the OSIRIS-REx mission, these findings heighten the mystery that has kept scientists on the edge of their seats.
When NASA’s spacecraft reached Bennu in December 2018, the asteroid gave its first surprise. Instead of the smooth, sandy beach, they had anticipated based on views from Earth- and space-based telescopes, the OSIRIS-REx team discovered a surface scattered with pebbles.
Additionally, researchers found that Bennu was spewing rock shards into space.
“Our assumptions about the asteroid’s surface were wholly inaccurate,” Lauretta stated.
The astounding discovery
The OSIRIS-REx mission collected a sample and sent breathtaking, up-close photographs of the asteroid’s surface to Earth, providing the most recent indication that Bennu was not what it first appeared to be. What we observed, according to Lauretta, was a massive wall of debris spreading out from the sample site. We exclaimed, “Holy cow!”
Given how lightly the spaceship had touched down, scientists were perplexed by the large number of pebbles that were scattered around. The fact that the spaceship left a massive crater that was 26 feet (8 metres) broad made the situation even stranger.
Every time we tested the sample gathering method in the lab, Lauretta reported, “We hardly made a divot.” To determine “how big of a mess we caused,” the mission crew opted to send the spacecraft back for additional photos of Bennu’s surface.
The amount of debris at the sample site, known as “Nightingale,” as shown in before and after photos,
was examined by mission scientists. Additionally, they examined the acceleration information gathered during the spacecraft’s touchdown. This information showed that OSIRIS-REx encountered a very little amount of resistance as it touched the asteroid, comparable to the amount of resistance one might encounter when pressing the plunger of a French press coffee carafe.
By the time we fired our thrusters to depart the surface, Ron Ballouz, an OSIRIS-REx scientist located at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, stated, “We were still diving into the asteroid.”
Based on spacecraft photos and acceleration data, Ballouz and the study team did countless computer simulations to determine Bennu’s density and cohesiveness. The surface cohesion characteristics of each simulation were altered by engineers until they discovered the one that most closely matched their real-life data.
Now that scientists have this detailed knowledge of Bennu’s surface, they can more accurately interpret observations of other asteroids made from a distance. This knowledge could be used to plan
future asteroid missions and to create strategies for shielding Earth from asteroid collisions.
Asteroids like Bennu, which are only tenuously held together by gravity or electrical force, could potentially disintegrate in Earth’s atmosphere and pose a different kind of threat than solid asteroids. According to Patrick Michel, an OSIRIS-REx scientist and the director of research at the Centre National de la Recherche Scientifique at the Côte d’Azur Observatory in Nice, France, “I think we’re still at the beginning of knowing what these bodies are.”