“A cosmic collision watched around the world”, writes Denise Show on the site of the television channel NBC News to describe what happened Tuesday, September 27 at 1:14 a.m. (Paris time), 11 million kilometers from Earth. A small NASA spacecraft thus intentionally crashed into an asteroid to test “humanity’s ability to protect the Earth from a potentially catastrophic impact” with such an object, continues the scientific journalist.
Named Dart – an acronym for Double Asteroid Redirection Test and word meaning “arrow” in English –, launched in November 2021, the probe “the size of a vending machine”crashed gloriously, at the speed of 22,000 km/h, on the surface “lumpy and gray” by Dimorphos, details the American monthly The Atlantic.
It is a small asteroid 163 meters in diameter (about half the size of the Eiffel Tower) orbiting around a second, slightly larger asteroid, Didymos. “A landscape so rich in texture you could almost feel the craggy rock against your fingertips” at the moment of impact, describes Marina Koren of The Atlantic, who observed the last hour and a half of Dart’s life on the live broadcast by the American space agency. “And then, nothing. The spacecraft crashed into the asteroid, its sophisticated cameras and all the rest of its delicate machinery shattered.”
The goal ? Divert the trajectory of the star a little bit.
defend the planet
Dimorphos evolves too far from Earth to pose any danger,”but the experiment is designed to test whether such an impact [avec une sonde] could make a difference if scientists discover an asteroid posing an imminent threat” for us, says the technology information site The Verge. A scenario similar to that ofArmaggedon by Michael Bay (1998) or the most recent Don’t Look Up by Adam McKay (2021), in short.
“At first glance, the mission might seem a bit silly (sorry, Nasa) ”, jokes Rae Paoletta in a tribune in the Washington Post. “Sounds like something Nathan Fielder might suggest in an episode of Nathan For You”, he continues, referring to a parody television series in which a fake consultant gives nonsensical advice to companies. “The plan ? Save the planet from a dangerous asteroid by hitting it with a multi-million dollar spaceship.”
“But this is not science fiction. In fact, my organization, the Planetary Society, has done planetary advocacy [sa] mission”, insists the editorial director of the organization, which strives “to educate the public […]to appeal to Congress for funding […]and to award grants to amateur astronomers working to understand near-Earth objects”. He will therefore look carefully at the results of the experiment.
Hera, the next mission
How will we know if Dart worked? The “arrow” is certain “to change the trajectory of the asteroid due to the fundamental physical laws of conservation of energy and momentum”, argues the scientific journalist of the New York Times Kenneth Chang. Non, “Dart will not refute Newton.“But the depth of the crater, which will not be the same if the asteroid is “solid” or “a pile of rubble held together by gravity”, will reveal to us the best strategy to adopt to deviate from similar ones.
Over the next few days, scientists will receive more images of Dimorphos, taken by the Light Italian Cubesat for Imaging Asteroids (LICIACube), “a tiny spaceship [de fabrication italienne] who accompanied Dart until earlier this month, and who flew over the impact site just three minutes after the collision, photographing the cloud of debris created by the collision”, reports the site space.com.
Then in 2024, it will be the European Space Agency (ESA) which will send a follow-up probe named Hera (Greek goddess of marriage and fertility), which unlike its predecessor will remain in the area to explore the binary asteroid system. . According to Meghan Bartels of space.com“the mission will give scientists better insight into the impact crater itself after the dust settles, as well as the natural state of the asteroids”. This new probe should arrive at the end of 2026 or the beginning of 2027. It will therefore be necessary to be patient.