After NASA deliberately crashed a spacecraft into an asteroid last year, the aftermath of that cosmic collision just got a lot more interesting.
DART space mission/ PHOTO: NASA
In a groundbreaking study published in the Planetary Science Journal, scientists discovered some unexpected results from NASA’s Double Asteroid Redirection Test (DART) mission. It appears that when DART slammed into the asteroid moon Dimorphos in 2022, it didn’t just leave a crater, it completely reshaped the celestial body and possibly set it on a chaotic new path, according to Study Finds.
What happened and why it matters
First, a quick recap: DART was NASA’s planetary defense test. The idea was to see if humans could change the course of an asteroid by hitting it with a spaceship – a sort of game of cosmic billiards. The target was Dimorphos, a small lunar asteroid orbiting a larger asteroid called Didymos.
According to Derek Richardson, a professor of astronomy at the University of Maryland and principal investigator on the DART mission, the impact did more than just deflect Dimorphos off course. It dramatically changed its shape.
Richardson explains that one of the biggest surprises was how much Dimorphos’ shape changed as a result of the DART mission. Originally, the asteroid’s moon was shaped like a hamburger, but the collision caused it to take the shape of a soccer ball.
This change in shape is very important because it calls into question what scientists thought they knew about how asteroid moons form. Previously, they believed that these moons naturally elongate over time, always pointing their long axis toward the main asteroid they orbit. However, Dimorphos flipped the script, going from crushed to sprawled upon impact.
“This result contradicts that idea and indicates that something more complex is at play here. Additionally, Dimorphos’s impact-induced shapeshift likely changed the way it interacts with Didymos.” Professor Richardson says in a university statement.
DART deflected the asteroid off course
The surprises did not stop at the change in the shape of the asteroid’s moon. The impact with the DART may have caused Dimorphos to roll through space in an unpredictable manner. Before the collision, Dimorphos was probably in a stable state, always showing the same face to Didymos (just as our Moon always shows the same face to Earth). Now it’s not like that anymore.
“Now, it’s out of alignment, which means it can wobble back and forth in its orientation,” explains Richardson. “Dimorphos could also ‘roll’, meaning he may have made her spin erratically and unpredictably.”
This unexpected flip raises new questions about the stability and internal structure of the asteroid. It could take a century or more for Dimorphos to settle back into a stable state, which has implications for future asteroid research and potential planetary defense strategies.
Speaking of future research, the European Space Agency is planning a follow-up mission called Hera to be launched in October 2024. Hera will arrive at the Didymos-Dimorphos system in late 2026 to study both asteroids up close and provide more details about the impact of DART. A key question that Hera could help answer is whether Dimorphos is stable enough for future spacecraft to land on.
“One of our biggest questions now is whether Dimorphos is stable enough for spacecraft to land and install more research equipment on it,” notes Richardson.
While all of this might sound like abstract space science, it has very real implications for the safety of our planet. The DART mission and its aftermath are helping scientists refine Earth’s defense strategies against potential asteroid or comet impacts.
“DART has given us insight into complicated gravitational physics that you can’t do in a lab, and all this research helps us calibrate our efforts to defend Earth in the event of a real threat. There is a chance that an asteroid or comet will approach and endanger the planet. Now, we have an additional line of defense against these types of external threats”concludes Richardson.
