Humanity has moved a celestial body for the first time, representatives of NASA’s Double Asteroid Redirection Test (DART), confirmed during a press briefing on Tuesday.
The DART mission slammed a refrigerator-sized spacecraft into an asteroid two weeks ago in the first-ever test of a defense system against annihilation by asteroid. When DART crashed into Dimorphos, a small rock that orbits a larger asteroid called Didymos, it shortened its orbit by a whopping 32 minutes. In other words, DART changed the time it takes for Dimorphos, which measures about 500 feet across, to orbit the half-mile-wide Didymos from 11 hours and 55 minutes to 11 hours and 21 minutes.
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Dimorphos and Didymos don’t pose a threat to Earth, but DART is the first test of planetary defense strategy in space that could help to thwart hazardous space rocks in the future.
“Two weeks ago NASA made history once again—we conducted humanity’s first planetary defense test,” said NASA administrator Bill Nelson during the briefing. “We showed the world that NASA is serious as a defender of this planet and we captured the attention of millions of people around the world in this test.”
“For the first time ever, humanity has changed the orbit of a planetary body, or a planetary object,” added Lori Glaze, director of the Planetary Science Division at NASA Headquarters in Washington, later in the briefing.
The test would have been considered a success if it had shifted Dimorphos’ orbit by just 73 seconds, but the result ended up exceeding that threshold by 25 times. The results will help scientists anticipate how to nudge any potentially hazardous space rocks into orbits that don’t overlap with Earth’s path around the Sun. The odds that our civilization will be threatened by a major impact are extremely low, but because of the apocalyptic nature of the risk, scientists think it is well-worth it to be prepared.
DART’s epic collision with Dimorphos has been imaged by a range of different telescopes on Earth and in space, producing spectacular images of this milestone in space exploration. Now, scientists have confirmed that the mission delivered on its core goal of moving a celestial object—and possibly helping to safeguard future generations.
