NASA (NASA) last year conducted a space experiment, with a detector hit an asteroid, the results not only changed the orbit of the asteroid but also dozens of boulders blasted into space.
The purpose of the experiment was to test a way to prevent future asteroids from crashing into Earth, and NASA directed the DART probe to an asteroid called Dimorphos, which is the moon of another, larger asteroid called Didymos. After the impact, the Hubble Space Telescope observed three months later that 37 previously undiscovered objects had appeared around the pair of asteroids, orbiting the sun alongside them. The study was published in the 21 July issue of Astrophysical Journal Letters.
Simulations show that these objects are not fragments that were crushed on impact, but rather boulders that bounced off Dimorphos intact. They may have been thrown from the surface by the energy generated by the impact or by seismic waves propagating inside Dimorphos after the impact. However, says David Jewett, a planetary astronomer at UCLA, “There’s a lot of uncertainty in this simulation.”
Based on the brightness of the objects, which are among the faintest Hubble has observed in the solar system, Jewett and colleagues estimate that the boulders could be 7 meters across and at least 15 objects over 4 meters. The researchers calculated that the boulders together weigh about 5 million kilograms, equivalent to the weight of 300 trucks loaded with gravel.
Hubble made several observations of the objects and found that they were moving away from Dimorphos and Didymos at an average speed of 1 kilometer per hour – slightly faster than the escape velocity of the pair of asteroid systems. So Jewett claims that these boulders, as well as many more small rocks that may be there but are invisible to Hubble, will eventually break out of the asteroid system’s orbit and orbit the sun on their own.
