File photo of the Double Asteroid Redirection Test, or DART, spacecraft.
A recent study suggests NASA's DART mission, designed to test asteroid deflection methods, may have revealed more than planned. While successfully altering the target asteroid's trajectory, scientists now believe the impact also significantly changed its shape, hinting at a surprising composition.
Previously thought to be a solid rock, Dimorphos, the impacted asteroid, may actually be a loose collection of debris. This conclusion stems from the unexpected level of deformation observed after the collision. Unlike a typical crater, the impact appears to have caused a broader, flatter dent, resembling an M&M candy.
This discovery, published in Nature Astronomy, has significant implications for our understanding of asteroids. It suggests that some, like Dimorphos, might be weaker and easier to deflect than previously thought. This information is crucial for developing future planetary defense strategies against potentially hazardous celestial objects.
"The asteroid acted like a fluid, which comes down to its peculiar composition. It's not a solid contiguous rock, but more like "a pile of sand," said Sabina Raducan, a planetary scientist at the University of Bern in Switzerland and the study's lead author. And a low-density asteroid barely held together by its own gravity was never going to respond in a straightforward manner when a van-size spacecraft flew into its face.
Dimorphos's response is "completely outside of the realm of physics as we understand it" in our day-to-day lives, said Cristina Thomas, the lead of the mission's observations working group at Northern Arizona University who was not involved with the study. "This has overarching implications for planetary defense."
According to The New York Times report, DART showed that a tiny spacecraft can deflect an asteroid. But the study indicates that crashing a similarly disjointed space rock too forcefully risks fragmenting it, which, in a real asteroid emergency, could create multiple Earthbound asteroids.
The DART mission serves as a crucial step in safeguarding our planet. While smaller space rocks pose minimal threat, larger ones could wreak havoc, ranging from localized destruction to global catastrophes. By understanding asteroid composition and testing deflection techniques, missions like DART pave the way for a more secure future.