Asteroid Dimorphos, which NASA deliberately hit with a rocket during the DART mission in September 2022, is behaving in unpredictable ways. Asteroid Dimorphos began exhibiting strange behavior after being hit by a NASA rocket last year, according to new data.

Recent observations of the approximately 580-foot-wide (177 meters) space rock that NASA intentionally crashed into a spacecraft as part of its Double Asteroid Redirection Test (DART) mission on September 26, 2022, suggest that Dimorphos may be falling. reports that it is in a generally stable orbit around the parent asteroid Didymos New Scientist. It was also found that Dimorphos was steadily slowing down in its orbit for at least a month after the rocket impact, contrary to NASA’s predictions.

California high school teacher Jonathan Swift and his students first discovered these unexpected changes while observing Dimorphos with his school’s 0.7-meter telescope last fall. A few weeks after the collision with DART, NASA announced that Dimorphos had slowed by approximately 33 minutes in its orbit around Didymos. But when Swift and his students examined Dimorphos a month after the impact, the asteroid appeared to have slowed by another minute, indicating that it had been slowing down steadily since the impact.

“The number we got was slightly higher, with a change of 34 minutes,” Swift told New Scientist. “It was disturbingly inconsistent.”

Swift presented his class’ findings at the American Astronomical Society conference in June. The DART team has since confirmed that Dimorphos continued to slow in its orbit for a month after the collision, but their calculations show an additional slowdown of 15 seconds, not a full minute. A month after the DART collision, the slowdown stabilized.

What caused Dimorphos to slow down steadily for a month before reaching equilibrium? A pile of space rocks may be to blame: Recent observations of an asteroid revealed that: an area of ​​large rocksRocks that probably escaped Dimorphos’ surface during the impact are scattered around. DART team member Harrison Agrusa told New Scientist it was possible that some of the larger rocks could fall on Dimorphos within the first month, slowing its orbit more than expected.

The DART team plans to release its own report on the unexpected findings in the coming weeks. But full answers may have to wait until 2026, when the European Space Agency’s Hera spacecraft will arrive at Dimorphos to closely examine the space accident.