NASA accidentally altered an asteroid’s solar orbit during its 2022 DART mission, marking the first time humanity has changed an asteroid’s path around the sun. A new study reveals that the mission’s impact on the moonlet Dimorphos also shifted the trajectory of its parent asteroid, Didymos. The DART mission, designed to test planetary defense by altering an asteroid’s path, targeted Dimorphos, a 525-foot-long moonlet orbiting the 2,550-foot-long asteroid Didymos. Neither object posed a threat to Earth, but the experiment aimed to demonstrate how a spacecraft could nudge an asteroid away from a potential collision. The mission succeeded in shifting Dimorphos’s orbit around Didymos by 33 minutes, far exceeding the 73-second target. However, the force of the impact also caused Didymos to move slightly along its solar path. Researchers explain that the collision’s energy disrupted Dimorphos, a rubble-pile asteroid, releasing debris that acted like a rocket’s jet, propelling Didymos backward. While the change in Didymos’s orbit was minuscule—equivalent to moving the asteroid the length of the Eiffel Tower over a year—the discovery highlights the unintended consequences of planetary defense experiments. Astronomers used stellar occultation observations to track the asteroid pair’s movement, finding that Didymos’s speed decreased by 22 millionths of a mile per hour. Though the shift was tiny, it underscores how even subtle changes in asteroid trajectories can accumulate over time. The study’s authors emphasize that the Didymos system remains safely distant from Earth, posing no immediate threat. The findings also provide insights into asteroid density. Dimorphos, with a density similar to water, behaved like a fluid during the impact, while Didymos, a denser, mountain-like object, resisted fragmentation.#nasa #dimorphos #didymos #dart_mission #european_space_agency
