Monday, a NASA spaceship hit an asteroid that was seven million miles away. The goal was to change its path.
Lauren (AFP): Bullseye: On Monday, a NASA spaceship hit an asteroid seven million miles away to change its path. This was a historic test of how well humans can stop a space object from destroying life on Earth.
The Double Asteroid Redirection Test (DART) impactor hit its target, the space rock Dimorphos, at 7:14 p.m. Eastern Time (23:14 gmt), 10 months after it took off from California on its first-ever mission.
“We’re entering a new era,” said Lori Glaze, head of NASA’s planetary science division. “In this new era, we might be able to protect ourselves from something like a dangerous asteroid impact.”
Didymos is a big brother asteroid that Dimorphos circles. Dimorphos is a 160-meter-tall (530-foot) asteroid that is about the same size as an Egyptian pyramid. The “moonlet,” which had never been seen before, showed up as a tiny point of light about an hour before the crash.
Its egg-like shape and rocky, boulder-covered surface became clear in the last few minutes as DART raced toward it at about 23,500 kilometres per hour (about 14,500 miles per hour).
NASA scientists and engineers cheered when the last image on the screen froze, letting them know that the signal had been lost and the spacecraft had hit the ground.
Related: NASA’s Dart spacecraft will strike the rock on Monday.
The two asteroids don’t pose any danger to Earth because they go around the Sun every two years.
But NASA thinks it’s important to do the experiment before a real need is found.
NASA hopes that if it hits Dimorphos head-on, it will move it into a smaller orbit, cutting 10 minutes off the time it takes to circle Didymos, which is currently 11 hours and 55 minutes.
Ground telescopes can’t see the asteroid system directly, but they can see changes in the way light comes from it. In the next few days and weeks, they should be able to give a definitive orbital period.
With the proof-of-concept, something that had only been tried in science fiction, like in the movies “Armageddon” and “Don’t Look Up,” is now a reality.
Astronomers are talking a lot –
LICIACube, a satellite about the size of a toaster that broke off from DART a few weeks ago, was supposed to make a close pass of the site minutes after impact to take pictures of the collision and the ejecta, which is the broken rock that was thrown off by the strike.
In the coming weeks and months, LICIACube’s pictures will be sent back.
A number of telescopes on Earth and in space, like the recently turned-on James Webb, are also watching the event. They might be able to see a brightening cloud of dust.
The mission has gotten astronomers all over the world excited, and more than 30 optical, radio, and radar ground telescopes are taking part.
Christina Thomas, a planetary astronomer on the DART mission, said, “There are a lot of them, and it’s so exciting that I’ve lost track of how many there are.”
In four years, a European Space Agency mission called Hera will arrive at Dimorphos to look at its surface and measure its mass, which scientists can only guess at right now. This will give scientists a full picture of what the system looks like.
People on Earth can sleep better.
We don’t think that many of the billions of asteroids and comets in our solar system could harm Earth, and none are expected to do so in the next hundred years or so.
But if you wait long enough, it will come true.
We know this from the geological record. For example, the Chicxulub asteroid, which was six miles wide and hit Earth 66 million years ago, caused a long winter that killed off the dinosaurs and 75% of all other species.
On the other hand, an asteroid the size of Dimorphos would only have a local effect, like destroying a city with more force than any nuclear bomb ever made.
Related: NASA’s InSight lander can see rocks from space as they hit Mars.
How much momentum DART gives Dimorphos will depend on whether it’s made of solid rock or more like a “trash heap” of boulders held together by gravity, which is not known yet.
If it had missed, NASA would have a second chance in two years, because the spaceship had just enough fuel for a second try.
But if it works, it will be the first step toward a world that can protect itself from an existential threat.
Elena Adams, a DART Mission Systems Engineer, said, “I think people on Earth can sleep better, and I know I will.”
