Bullseye: A NASA spacecraft slammed into an asteroid seven million miles away Monday to deflect its orbit, passing a historic test of humanity’s ability to prevent a celestial body from destroying life on Earth.
The Double Asteroid Redirection Test (DART) impactor struck its target, the space rock Dimorphos, at 7:14 p.m. Eastern Time (2314 GMT), 10 months after launching from California on its pioneering mission.
“We are entering a new era, an era where we may have the opportunity to protect ourselves from something like a dangerously dangerous asteroid impact,” said Lori Glaze, director of NASA’s division of planetary science.
Dimorphos — a 530-foot (160 meters) asteroid roughly comparable in size to an Egyptian pyramid — orbits a half-mile-long big brother named Didymos. Never seen before, the “moonlet” appeared as a speck of light about an hour before impact.
Its egg-like shape and steep, boulder-strewn surface finally came into focus in the last few minutes, as DART raced toward it at about 23,500 kilometers per hour.
NASA scientists and engineers burst into applause as the screen froze on a final image, indicating that the signal had been lost and the impact had occurred.
To be sure, the pair of asteroids pose no threat to our planet, as they orbit the sun every two years.
But NASA has considered the experiment important to conduct before an actual need is discovered.
By attacking Dimorphos head-on, NASA hopes to push it into a smaller orbit, saving 10 minutes off the time it takes to encircle Didymos, which is currently 11 hours and 55 minutes.
Ground-based telescopes — which can’t see the asteroid system directly, but can detect a shift in light patterns — should provide a definitive orbital time in the coming days and weeks.
The proof-of-concept has made a reality of what was previously only attempted in science fiction, particularly in films like “Armageddon” and “Don’t Look Up.”
– Astronomy community is buzzing –
Minutes after the collision, a toaster-sized satellite called LICIACube, which had already separated from DART a few weeks ago, was expected to pass the site at close range to capture images of the collision and the ejecta – the pulverized rock that by the strike.
The LICIACube photos will be returned in the coming weeks and months.
Also watch the event: a series of telescopes, both on Earth and in space – including the recently operational James Webb – that may be able to spot a brightening cloud of dust.
The mission has shaken the global astronomy community, with more than three dozen ground-based telescopes taking part, including optical, radio and radar.
“There are a lot of them, and it’s incredibly exciting to lose count,” said planetary astronomer Christina Thomas of the DART mission.
Finally, a full picture of what the system will look like will be revealed when a mission from the European Space Agency called Hera arrives four years later to survey the surface of Dimorphos and measure its mass, which scientists can currently only guess at.
– ‘Earthlings can sleep better’ –
Very few of the billions of asteroids and comets in our solar system are considered potentially dangerous to our planet, and none are expected in the next hundred years or so.
But wait long enough, and it will happen.
We know that from the geologic records — for example, the 10-kilometer-wide Chicxulub asteroid slammed into Earth 66 million years ago and plunged the world into a long winter that led to the mass extinction of the dinosaurs, along with 75 percent of all dinosaurs. types.
An asteroid the size of Dimorphos, on the other hand, would only have a regional impact, like destroying a city, albeit with more force than any atomic bomb in history.
How much momentum DART gives to Dimorphos depends on whether the asteroid is solid rock, or more like a “garbage heap” of boulders bound by mutual gravity — a property not yet known.
If it had missed, NASA would have another shot in two years, with the spacecraft having just enough fuel for one more pass.
But its success marks the first step towards a world capable of defending itself against a future existential threat.
“I think Earthlings can sleep better, I definitely will,” said DART mission system engineer Elena Adams