![]() ![]() Three minutes after the collision, a cubesat called LICIACube arrived to surveil the wreckage. Making sure this strategy works will require some careful follow-up observations, and an impressive array of instruments have swiveled to monitor the Didymos system. It was more of a flick-a nudge that packed enough of a punch to change the moonlet’s orbit without smashing it into pieces. But unlike movie plots to blow up asteroids before they hit the planet, the DART impact wasn’t an attempt to obliterate Dimorphos. The collision resembles the desperate, last-minute attempts to save Earth from cosmic annihilation in Hollywood blockbusters. Teams recently named the space rock Dimorphos, which is Greek for “having two forms”-one before the impact, and one after. ![]() But no one had ever gotten a good look at its tiny moonlet until just before DART smashed into it. ![]() As it approached, the spacecraft furiously snapped images of Dimorphos, which rapidly grew from a pinprick of light to fill its field of view-until the moment of impact, when everything went dark.ĭimorphos orbits a larger asteroid called Didymos, and the two asteroids are not considered threats to Earth-which is one of the reasons NASA put them in the DART spacecraft’s crosshairs for this first planetary defense test.ĭiscovered in 1996, Didymos, which means “twin” in Greek, is roughly a half-mile across and relatively well studied. To practice shaping that reality, NASA sent DART hurtling toward its demise. “This is just the first step, but isn’t it exciting that we’re going from science fiction to science reality?” “I don’t really lose sleep about the Earth getting destroyed by asteroids, but I am excited about living in a world where we might be able to potentially prevent this in the future,” says Nancy Chabot of Johns Hopkins University’s Applied Physics Laboratory (APL) in Laurel, Maryland, which manages the DART mission. And eventually, whether in hundreds or thousands or millions of years, it is all but certain that life on Earth will face an existential threat from an asteroid. While scientists are confident that a large enough asteroid to cause planet-wide extinction will not threaten Earth for at least a hundred years-after which time it is difficult to predict their orbits-it is still possible that we could be surprised by a smaller, potentially city-destroying rock from space. ![]() It's also the first test of a bold strategy that could be used to deflect any future asteroids that are on a collision course with Earth. ET, marks the first time humans have intentionally changed the course of a celestial object. The collision between NASA’s Double Asteroid Redirection Test (DART) spacecraft and a 500-foot-wide rock called Dimorphos, which took place at 7:14 p.m. The blast-off was shown live on Nasa TV and on the SpaceX Twitter account.Laurel, MarylandNearly seven million miles from Earth, a spacecraft traveling more than 14,000 miles an hour smashed into a small, unsuspecting asteroid that had been floating through space undisturbed for eons. The team behind Dart chose the Didymos system because its relative proximity to Earth and dual-asteroid configuration make it ideal for observing the results of the impact. But scientists say smaller asteroids are far more common and pose a greater theoretical danger in the near term. The asteroid being targeted by Dart poses no actual threat and is tiny compared with the cataclysmic Chicxulub asteroid that struck Earth 66m years ago, leading to extinction of the dinosaurs. Cameras mounted on the impactor and on a briefcase-sized mini-spacecraft to be released from Dart about 10 days beforehand will record the collision and beam images of it back to Earth. Once there Dart will test its ability to alter an asteroid’s trajectory with sheer kinetic force. The Dart payload, about the size of a small car, was released from the booster minutes after launch to begin its 10-month journey into deep space, some 6.8 million miles (11 km) from Earth. If the mission is successful, it will mean that Nasa and other space agencies could deflect an asteroid heading towards Earth and avert an Armageddon-style impact. The plan is to crash the robot spacecraft into the moonlet Dimorphos at 15,000mph (24,100km/h) and change its path by a fraction. ![]()
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