Bullseye: A NASA spacecraft struck a asteroid 7 million miles away in order to divert its orbit, passing a historic test of humanity’s ability to prevent a celestial object from devastating life on Earth.
The double asteroid redirect test (DART) the impactor hit its target, the space rock Dimorphos, at 7:14 p.m. Eastern Time (23:14 GMT), 10 months later explode of California on his pioneering mission.
“We are entering a new era, an era in which we potentially have the ability to protect ourselves against something like a dangerous dangerous asteroid impact,” said Lori Glaze, director of NASA’s planetary science division.
Below is the latest full image captured by DART’s onboard camera.
Dimorphos — a 530-foot (160-meter) asteroid roughly comparable in size to an Egyptian pyramid — orbits a half-mile-long big brother called Didymos. Never seen before, the “moonlet” appeared as a point of light about an hour before the collision.
Its egg-like shape and steep, boulder-strewn surface finally became clear in the final few minutes, as DART raced towards it at around 14,500 miles (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.
Certainly, the pair of asteroids pose no threat to our planet because they circle the Sun every two years.
But NASA deemed the experiment important to perform before a real need was discovered.
By hitting Dimorphos head-on, NASA hopes to push it into a smaller orbit, slashing the time it takes to circle 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.
The proof of concept achieved what had only been attempted before in science fiction – notably in films such as Armageddon and Don’t look up.
This was the last image captured by DART.
The astronomical community in turmoil
Minutes after impact, a toaster-sized satellite called LICIACube, which had already separated from DART a few weeks ago, was expected to pass the site closely to capture images of the collision and ejecta – the pulverized rock thrown out by the strike. .
LICIACube photos will be sent back in the coming weeks and months.
Also watching the event: a network of telescopes, both on Earth and in space – including the recently operational James Webb – who might be able to see a lightening cloud of dust.
The mission sent the global astronomy community into a frenzy, with more than three dozen ground-based telescopes participating, including optical, radio and radar.
“There are a lot of them, and it’s incredibly exciting to have lost count,” said Christina Thomas, planetary astronomer on the DART mission.
Finally, a full picture of what the system looks like will be revealed when a European Space Agency mission called Hera in four years arrives to survey Dimorphos’ surface 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 within the next hundred years.
But wait long enough and it will happen.
We know that 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 mass extinction from dinosaurs with 75 percent of all species.
A Dimorphos-sized asteroid, on the other hand, would only have a regional impact, like devastating a city, but with greater force than any nuclear bomb in history.
The amount of momentum DART imparts to Dimorphos will depend on whether the asteroid is solid rock, or rather a “garbage pile” of rocks bound together by mutual gravity – a property that is not yet known.
If it had missed, NASA would have 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 from a future existential threat.
“I think Earthlings can sleep better, I definitely will,” said Elena Adams, DART mission systems engineer.