LAUREL, USA – Bullseye: A NASA spacecraft struck an asteroid seven million miles away on Monday to divert its orbit, successfully passing a historic test of humanity’s ability to stop a celestial object from killing the life on Earth.
The Double Asteroid Redirection Test (DART) impactor hit its target, the space rock Dimorphos, at 7:14pm Eastern Time (2314 GMT), 10 months after it launched from California on its pioneering mission.
“We are entering a new era, an era where we may be able to protect ourselves from something like a dangerous asteroid impact,” said Lori Glaze, director of NASA’s planetary science division.
Dimorphos — a 530-foot (160-meter) asteroid roughly comparable in size to an Egyptian pyramid — orbits an 800-meter-long big brother named Didymos. Never seen before, the “moon” appeared as a patch of light about an hour before the collision.
Its egg-like shape and jagged, boulder-strewn surface were finally brought into focus in the final few minutes as DART hurtled towards it at around 14,500 miles (23,500 kilometers) per hour.
NASA scientists and engineers cheered as the screen froze in a final frame, indicating that signal had been lost and an impact had occurred.
True, the two asteroids do not pose a threat to our planet, since they orbit the sun every two years.
However, NASA deemed it important to conduct the experiment before an actual need was discovered.
By hitting Dimorphos hard, NASA hopes to put it into a smaller orbit, slashing the time it takes to orbit Didymos by 10 minutes from the current 11 hours and 55 minutes.
Ground-based telescopes – which cannot see the asteroid system directly but can detect a change in the patterns of light coming from it – should provide a definitive orbital period in the days and weeks to come.
Proof of concept made possible what had previously only been attempted in science fiction – especially in films like Armageddon and Don’t Look Up.
ASTRONOMY COMMUNITY ABUZZ
Minutes after impact, a toaster-sized satellite called LICIACube, which separated from DART a few weeks ago, was expected to pass nearby to capture images of the collision and ejecta – the pulverized rock projected by the affected rocket.
LICIACube images will be returned in the coming weeks and months.
Also watching the event are a number of telescopes, both on Earth and in space – including the recently commissioned James Webb – which may be able to see a clearing cloud of dust.
The mission has excited the global astronomy community, with more than three dozen ground-based telescopes participating, including optical, radio and radar telescopes.
“There are a lot of them, and it’s incredibly exciting to have lost track of them,” said DART mission planetary astronomer Christina Thomas.
Eventually, a full picture of what the system looks like will be revealed when a European Space Agency mission called Hera arrives in four years to probe Dimorphos’ surface and measure its mass, which scientists can only guess for the moment.
THE EARTH CAN SLEEP BETTER
Of the billions of asteroids and comets in our solar system, very few are considered potentially dangerous to our planet, and none are expected within the next hundred years.
But wait long enough and it will happen.
We know this from the geological record – for example, the six-mile-wide asteroid Chicxulub hit Earth 66 million years ago, plunging the world into a long winter that led to the mass extinction of dinosaurs as well than 75% of all species.
In contrast, an asteroid the size of Dimorphos would only have regional effects, like devastating a city, but with greater force than any atomic bomb in history.
The amount of momentum DART gives Dimorphos depends on whether the asteroid is solid rock or rather a “garbage pile” of rocks bound together by gravity – a property that is not yet known.
Had it missed, NASA would have had another shot in two years, with the spacecraft containing 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 Elena Adams, system engineer for DART missions.
- Editor/ additional report by AFP
