If there is a possibility Asteroid It is said that Bennu hitting the earth for life from now on will keep you awake at night, and NASA scientists think you can rest more easily.
The agency’s Osiris-Rex The spacecraft spent more than two years orbiting tightly around this space rock.With incredible detailed views of asteroids, experts have studied potential space rock impacts Earth They have been able to fine-tune their existing Bennu future models.
Therefore, the scientists supporting the new research now say that they believe that the total impact probability of this asteroid before 2,300 years is only one in 1,750.The estimates generated before OSIRIS-REx reaches the space rock are calculated Bennu The impact between 2175 and 2199 is one in 2,700, According to NASANASA said that although the risk is slightly higher than previous estimates, it represents a small change in an already insignificant risk.
Technically, this is only a small increase in risk, but the scientists behind the new study say they are not worried about the potential impact. In addition, the experience and lessons provided by the study for asteroid trajectory calculations can reduce concerns about the potential impact of other asteroids, and make up for it.
Lead author Davide Farnocchia, who works at NASA’s Near-Earth Object Research Center, said at a press conference: “The probability of impact has only risen slightly, but it has not changed much. The probability of impact is almost the same.” It was held on Wednesday (August 11). “I think that overall, the situation has improved.”
OSIRIS-REx (officially named Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) was launched in September 2016, Slide into the track Orbit the asteroid Bennu in December 2018.
After the spacecraft arrived, it took nearly two and a half years to study space rocks from orbit, dive in, hover overhead, and inspect the rocks in every possible way.
Dante Lauretta, planetary scientist at the University of Arizona, OSIRIS-REx lead researcher, and author of the new study, said at a press conference: “The trajectory of the spacecraft is really amazing-I liken it to a hummingbird.”. “We can get into orbit. , We can leave orbit, we can enter various imaging angles.”
During that time, the spacecraft continuously recorded its position relative to the earth and asteroids. Using this data, the team behind the new research was able to fine-tune their understanding of the location and movement of space rocks for nearly two and a half years.
The spacecraft’s visit to the asteroid reached its climax in October 2020, when OSIRIS-REx Snatched Bennu’s sample Hide it. In May, the spacecraft and its precious cargo will bid farewell to the asteroid and return to Earth. OSIRIS-REx will store the sample chamber there in September 2023. This delivery will provide scientists with a rare opportunity that must be provided by ground-based laboratories that use all cutting-edge equipment to study asteroid materials.
But scientists do not need to touch these sample materials to gain insight into the spacecraft’s two and a half years of observations. Coupled with the work of astronomers observing Bennu from the ground before OSIRIS-REx even an idea, scientists have about 20 years of data tracking individual space rocks.
Scientists’ asteroid trajectory models always contain a certain degree of uncertainty, because when space rocks rattle inside, they are pulled by multiple forces. Solar systemEven in the new and improved models of Bennu’s future path, this uncertainty still exists, but through OSIRIS-REx observations, scientists can significantly reduce their uncertainty about Bennu’s fate.
Among other factors, the researchers were able to explain the tiny orbital changes, including solar radiation, the influence of relativity, and the gravitational pull of hundreds of other relatively large asteroids whizzing nearby.
In addition to factors like these that affect all solar system objects (although the impact is small), the team was able to specifically examine the effects of two unusual features of Bennu: dusty Regular launches of asteroids and the interaction of rocks with the spacecraft itself.
One factor that scientists are particularly concerned about is called the Yakovsky effect, which is triggered by the constant temperature fluctuations that occur when the asteroid region enters and exits under sunlight, gently pushing the asteroid.
“The Yarkovsky effect on Bennu is equivalent to the weight of three grapes,” Farnocchia said. “This is what really pushed the Bennu movement into the future, because this acceleration is long-lasting, and its influence will increase over time. When you reach the year 2135, it becomes very important.”
However, despite the scientists’ best efforts, predicting Bennu’s course after 2135 is still tricky. In September of that year, Bennu will pass the Earth-not close enough to risk any impact, but certainly close enough that the gravity of the Earth can slightly push the asteroid to move in its orbit. In the next few decades and centuries, the precision of this dance will shape Bennu’s trajectory.
Due to uncertainties and other similar events that may occur in the future, scientists now state that, according to a study, Bennu’s total impact probability by 2300 is about one in 1,750. NASA statement About new research. During this time, the most worrying date was September 24, 2182; even on that day, Bennu’s collision probability was only one in 2,700.
Of course, Bennu is not the only space rock that scientists worry about. Planetary Defense is dedicated to identifying all asteroids that may affect the Earth in a meaningful way. One aspect of this work is to find as many near-Earth asteroids as possible-so far, scientists have cataloged more than 26,000, According to NASA.
But in order to accurately determine which asteroids may actually pose a risk, scientists need to be able to calculate as accurately as possible where the trajectory of the space rock will go. Of course, this trajectory is based on existing observations of the location of the asteroid, but scientists have known for years that factors such as the Yakovsky effect may confuse their calculations.
The researchers said that the new data from OSIRIS-REx quantifies the Yarkovsky effect of the triple grape weight and should help scientists understand how the same effect shapes the trajectories of other asteroids.
“For the first time, we were able to test our model in an asteroid orbit, reaching a level that had never been tried before,” said Fano. “The results generally apply to all other asteroids, and we can apply these models and be confident that they are very accurate.”
The study is described in Paper Published in the journal on Tuesday (August 10th) Icarus.
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