![]() Perhaps more likely, however, is the second idea, as Harrison Agrusa, a DART team member at the Côte d’Azur Observatory in France who was not involved in the new research, tells New Scientist. If this is the case, Veres says, Dimorphos will likely settle back into a tidally locked state over time. But now, after the DART mission, this alignment might have been broken, causing Dimorphos to tumble around as the system’s tidal forces change its orbit. One idea is that Dimorphos was once tidally locked to Didymos-meaning that, like Earth’s moon, the same side of the satellite always faced its host. According to Veres, the team relied on a widely used method and gathered enough data points to conclude that Dimorphos’ orbit is degrading.Īs for why this may be happening, scientists only have guesses so far. Swift’s team shared their surprising new research at a meeting of the American Astronomical Society in June and posted a preprint of their paper on the online server Arxiv in August. “Instead, we already knew from ground-based observations and several space missions that asteroids are often rubble piles-loosely aggregated spheres of large and small boulders, dust and sometimes ice, with numerous empty spaces.” Hitting one of these asteroids, Veres says, is almost more like striking a sponge than a rock, and it’s harder to predict the impact’s results. “If an asteroid were constructed as a monolithic rock, similar to the rocks we find on the ground, the deflection and calculations would be straightforward,” Peter Veres, an astronomer at the Center for Astrophysics, Harvard & Smithsonian, who was not involved in the study, tells Smithsonian magazine in an email. Prior to DART, no other mission had ever conducted a planetary defense test, so Dimorphos is the only real-world example to learn from. “We tried our best to find the crack in what we had done, but we couldn’t find anything.”ĭimorphos’ unexpected behavior is not a cause for alarm-the asteroid still poses no threat to Earth-but it could teach scientists more about asteroid deflection. “That was inconsistent at an uncomfortable level,” Jonathan Swift, a math and science teacher at the Thacher School who took part in the research, tells New Scientist. The finding brought the asteroid’s orbital period to 34 minutes shorter than it was pre-impact. ![]() From September to early November last year, a high school teacher and his students used the observatory at their California school to study the asteroid, and they found its orbit had decreased by another full minute compared to NASA’s numbers, reports New Scientist’s Jonathan O’Callaghan. ![]() It looked like a tidy conclusion to a tale of success, but according to new research, the story didn’t end there. The tiny-but-mighty DART craft shortened Dimorphos’ orbital period, or the time it takes to circle Didymos, by about 33 minutes. Dimorphos orbits another asteroid called Didymos, and while neither object posed a threat to Earth, the feat showed the world that NASA could nudge an asteroid and alter its trajectory-an action that might come in handy if a planetary defense scenario were to materialize in the future. In a first-of-its-kind feat, the agency’s Double Asteroid Redirection Test (DART) craft slammed into the space rock Dimorphos at 14,000 miles per hour on September 26, 2022. Nearly a year has passed since NASA deliberately crashed a $300 million spacecraft into an asteroid. ![]()
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