Last year saw NASA’s first mission to protect the planet with the Double Asteroid Redirection Test (DART). The goal was to change the orbit of the Dimorphos satellite to demonstrate that an asteroid could be redirected in the event of a catastrophic approach to Earth. The collision of the spacecraft with Dimorphos not only changed the satellite’s orbit, but also resulted in the scattering of 37 pieces of debris, some of which were up to 7 meters wide.
The DART mission, watched with interest around the world on September 26, 2022, successfully changed the orbit of Dimorphos from 11 hours 55 minutes to 11 hours 23 minutes after the collision.
By demonstrating the effectiveness of humanity’s ability to prevent asteroid catastrophe, this dramatic event inadvertently set off a chain reaction in space. The mission’s aftermath has led to a discovery that is both fascinating and disturbing.
The University of California at Los Angeles (UCLA) recently conducted a study analyzing the consequences of DART’s high-speed collision with Dimorphos.
David Javitt, the study’s lead astronomer, compared the effects to debris propagating from a hand grenade at speeds of up to 13,000 miles per hour.
“Because these large boulders almost share the velocity of the target asteroid, they are capable of doing their own damage,” Javitt explained.
To understand the potential dangers of these boulders, Javitt mentioned that a 15-foot-tall boulder colliding with Earth at these speeds would release energy comparable to the atomic bomb that destroyed Hiroshima during World War II.
However, it is worth noting that none of the boulders resulting from the DART mission are on a collision course with Earth.
Dimorphos itself has never been a direct threat. Located six million miles from our planet, it served as an ideal test site – close enough for observations, but far enough away to rule out immediate consequences.
Surprising discoveries about the consequences of the DART mission were made possible by images taken by the Hubble Space Telescope in December 2022.
These photos showed boulders ripped away from the surface of Dimorphos, both from a direct impact and possibly from seismic vibrations caused by the collision.
Pre-collision DART images showed boulders of similar size and shape on the asteroid’s surface, confirming the Hubble telescope results.
“The boulders we studied are some of the faintest objects ever seen in the solar system, and observing them in detail is possible thanks to the powerful Hubble telescope,” Javitt said.
“If we follow the boulders in future Hubble observations, we may have enough data to pinpoint the boulders’ trajectories. And then we’ll see in which directions they were launched from the surface and figure out how they were ejected.”
The study, published in Astrophysical Journal Letters, highlights the complexities of space missions. While the DART mission is a testament to human ingenuity in protecting the planet, it is also a reminder of the unpredictable nature of space and the cascading effects of our interventions.