NASA’s DART Mission Reveals Surprising Effects on Asteroid Dimorphos
In a groundbreaking mission, NASA’s DART probe collided with the asteroid Dimorphos in September 2022, resulting in unexpected changes to the tiny asteroid’s shape. This collision has provided valuable insights into the formation of asteroids and has significant implications for future asteroid redirection missions.
The DART mission, short for Double Asteroid Redirection Test, aimed to determine if it was possible to alter the course of an asteroid by deliberately crashing a spacecraft into it. Dimorphos, a small asteroid in a mutual orbit with its larger binary companion Didymos, was chosen as the target. Scientists monitored changes in the timing of the binary object’s orbit to gauge the success of the mission.
The impact had a more significant effect on the orbital period than anticipated, marking a successful mission. However, scientists were unsure if there would be any ongoing effects or what they might reveal about Dimorphos. To investigate further, a team led by planetary scientist Sabina Raducan from the University of Bern in Switzerland conducted simulations to replicate the observed impact effects.
The simulations focused on variables such as the transfer of momentum from the spacecraft to the asteroid, the amount of material ejected from Dimorphos, and the shape that material formed as it dispersed into space. By adjusting unknown factors like the composition and density of Dimorphos, the team produced simulations consistent with the observed results.
The simulations revealed that Dimorphos is a weak rubble pile held together loosely. The impact did not leave a scar on the surface but instead caused global deformation and resurfacing. This finding suggests that Dimorphos is similar to other asteroids like Ryugu and Bennu, which have been visited by human spacecraft for data and sample collection.
Furthermore, the simulations indicated that Dimorphos has a very low density of around 2.4 grams per cubic centimeter. While slightly denser than Ryugu and Bennu, which have densities of 1.28 and 1.26 grams per cubic centimeter respectively, Dimorphos is significantly less dense than Earth, which has a density of 5.51 grams per cubic centimeter.
These findings support the hypothesis that Dimorphos is the offspring of Didymos. Both asteroids are classified as rubble piles, and the simulations suggest that Dimorphos formed from debris shed by Didymos due to centrifugal force. Over time, this debris clumped together to create the loose rubble pile that was impacted by the spacecraft.
The implications of these findings extend beyond the understanding of this binary asteroid system. They provide valuable information for studying the formation and characteristics of binary asteroids and will inform future exploration and asteroid deflection efforts. The upcoming Hera mission by the European Space Agency, scheduled to launch later this year, will further investigate Didymos and Dimorphos. If Hera’s findings align with the team’s simulations, our knowledge of Dimorphos will be greatly expanded.
In conclusion, the collision between NASA’s DART probe and the asteroid Dimorphos has yielded surprising results regarding the asteroid’s shape and composition. Through simulations, scientists have discovered that Dimorphos is a weak rubble pile with a low density. These findings shed light on the formation of binary asteroids and have implications for future asteroid redirection missions. As we await the results of the Hera mission, we anticipate further revelations about Dimorphos and its role in our understanding of asteroids in our solar system.
