Because of some stunning Hubble Space Telescope observations, scientists proceed to be surprised by NASA’s DART mission – this time in the shape of a swarm of boulders that appears to have been knocked loose from the targeted asteroid upon impact.
In September of last 12 months, NASA launched a mission that, on its surface, might appear to contradict every part we find out about space exploration. The agency launched a spacecraft directly into an asteroid. It didn’t survive. But this metal adventurer, named DART, which stands for Double Asteroid Redirection Test, had an important purpose: It was NASA’s first step in developing an ambitious planetary defense system.
In a nutshell, the goal of DART was to see whether the craft’s crash-landing on a comparatively small asteroid named Dimorphos would alter its orbit around a bigger asteroid, Didymos. Not only was the mission a powerful success, nevertheless it also appears to be the gift that keeps on giving. We have since learned quite a bit about space rock impacts and the way, exactly, a futuristic Earth defense mechanism might work in the future.
And on Thursday (July 20), NASA announced that DART has provided us with some intriguing information yet again from beyond the grave. By tapping into the Hubble Space Telescope’s powerful optics, astronomers found that the probe’s impact on Dimorphos – which occurred while it flew at about 14,000 mph (22,530 km/h) – produced a “swarm of boulders.” And it’s possible, the agency says, that these shards got here from the asteroid goal itself.
Related: DART’s epic asteroid crash: What NASA has learned 5 months later
“This tells us for the primary time what happens once you hit an asteroid and see material coming out as much as the biggest sizes,” David Jewitt, a planetary scientist on the University of California at Los Angeles focused on DART impact studies, said in a press release. “The boulders are among the faintest things ever imaged inside our solar system.”
Nonetheless, to be clear, a press release on these results points out that the boulders were likely not shattered away from Dimorphos consequently of DART’s collision, but reasonably that they already existed on the surface of the asteroid and were merely dispersed upon impact. In truth, DART’s final image of the asteroid prior to its demise, taken two seconds before impact, shows such mini-rocks and debris already present on Dimorphos.
In keeping with NASA’s statement, the boulders’ ejection could’ve either been as a result of what’s often known as an ejecta plume produced by the collision, or a seismic wave that shook them off. (The latter could be much like what would occur if you happen to hit a loose rocky surface with a hammer, causing small rocks to shake free across the surface.)
By way of the boulders themselves, Jewitt and fellow researchers identified 37 free-flung rocks spurting off of Dimorphos that range in size from three feet to 22 feet (.9 meters to six.7 meters) across and have a collective mass about 0.1% the mass of the asteroid. These objects seemed to be drifting away from their source at just over a half-mile per hour (0.8 km/h), which NASA likens to “roughly the walking speed of an enormous tortoise.”
“It is a spectacular commentary – significantly better than I expected,” Jewitt said. “We see a cloud of boulders carrying mass and energy away from the impact goal. The numbers, sizes, and shapes of the boulders are consistent with them having been knocked off the surface of Dimorphos by the impact.”
“If we follow the boulders in future Hubble observations,” Jewitt added, “then we can have enough data to pin down the boulders’ precise trajectories. After which we’ll see wherein directions they were launched from the surface.”