Almost a year ago, NASA accomplished a groundbreaking feat by successfully redirecting an asteroid, marking a significant step in our ability to avert a potential asteroid crashing into the Earth.
However, this story has an intriguing twist, as the asteroid appears to be behaving unexpectedly.
Change in course
As reported by New Scientist, a schoolteacher and his students have noticed peculiar behavior in the orbit of Dimorphos, the asteroid that NASA’s Double Asteroid Redirection Test (DART) impacted last September.
Jonathan Swift, a math and science teacher at the Thacher School in California, and his team of student astronomers made the discovery. Dimorphos orbits the giant near-Earth asteroid Didymos, akin to how our Moon orbits Earth, and it has been consistently slowing down in its orbit around Didymos since the DART test.
Mission successful, but to what end?
It’s crucial to note that altering Dimorphos’ trajectory was the primary goal of the DART test. NASA confirmed shortly after the collision last fall that the mission achieved its objective, reducing the asteroid’s orbit duration from 11 hours and 55 minutes to 11 and 23 minutes.
This was well within the parameters of NASA’s “minimum successful orbit period change” of 73 seconds, affirming the success of the DART test in demonstrating our capability to divert near-Earth asteroids.
However, when Swift and his team observed Dimorphos’ orbit more than a month after the collision, they found that the asteroid’s orbit continued to slow down, which was an unexpected development. Most astronomers anticipated it would revert to its original orbit speed relatively quickly.
Too good to be true?
Swift explained, “The number we got was slightly larger, a change of 34 minutes. That was inconsistent at an uncomfortable level.”
Although NASA had mentioned a margin of error of plus or minus two minutes in its initial post-DART findings regarding the orbit slowing, this change is still surprising.
Some theories suggest that the impact might have altered Dimorphos’ orbit or released it from the gravitational forces of Didymos.
Despite their efforts to scrutinize their findings, Swift and his team could not identify any errors in their calculations.
NASA is also planning to release a report on the latest developments of the DART mission, as confirmed by a spokesperson. However, they will be competing with Swift and his students, who have shared their findings with the American Astronomical Society, which is set to publish their paper shortly.