Movies that imagine an asteroid or comet colliding catastrophically with Earth always feature a key scene:
a lone astronomer sees the wandering chunk of space hurtling towards us, causing panic and a growing sense of existential dread as the researcher tells the rest of the world.
On March 11, life began to imitate art.
That night, at the Piszkéstető hill station of the Konkoli Observatorynear Budapest, Krisztián Sárneczky looked at the stars.
Dissatisfied with the discovery of 63 near-Earth asteroids throughout his career, he was on a quest to find 64, and he succeeded.
At first, the object he saw seemed normal.
“It wasn’t unusually fast,” Sarneczky said.
“It wasn’t unusually bright.”
Half an hour later, he noticed that “his movement was faster.
That’s when I realized it was fast approaching us.”
That may sound like the beginning of a melodramatic disaster movie, but the asteroid was just over 1.8 meters long, a harmless nothing.
And Sarneczky was elated.
“I have dreamed of such a discovery many times, but it seemed impossible,” he said.
Not only had he spied a new asteroid, but he had detected one just before it hit planet Earth, only the fifth time such a discovery is made.
The object, later named 2022 EB5, may have been harmless, but it ended up being a good test of the tools NASA has built to defend our planet and its inhabitants from a collision with a more threatening rock from space.
One of those systems Scout, is software that uses astronomers’ observations of near-Earth objects and calculates roughly where and when their impacts may occur.
When it came to detecting 2022 EB5, Sárneczky shared his data and Scout quickly analyzed it.
Although 2022 EB5 was due to hit Earth just two hours after its discovery, the software managed to calculate that it would enter the atmosphere off the east coast of Greenland.
And at 5:23 p.m. ET on March 11, it did exactly that, exploding in midair.
“It was a wonderful hour and a half in my life,” Sarneczky said.
Although EB5 was rare, it doesn’t take a huge jump in size for an asteroid to become a threat.
The 16-meter rock that exploded over the Russian city of Chelyabinsk in 2013, for example, unleashed an explosion equivalent to 470 kilotons of TNT, shattering thousands of windows and injuring 1,200 people.
That Scout can accurately plot the path of a smaller asteroid offers a way to tranquillity.
If detected early enough, a city facing a future Chelyabinsk-like space rock can at least be warned.
Normally a few days of observations are needed to confirm the existence and identity of a new asteroid.
But if that object turns out to be a small but dangerous space rock about to collide with Earth, deciding to wait for that additional data first could have disastrous results.
“That’s why we developed Scout,” said Davide Farnocchia, a navigation engineer at the Jet Propulsion Laboratory who developed the program, which was launched in 2017.
Scout is constantly looking at data published by the Minor Planet Center, a clearinghouse in Cambridge, Massachusetts, that notes the discoveries and positions of small space objects.
The software then “tries to figure out if something is headed for Earth,” Farnocchia said.
That Sárneczky was the first to detect 2022 EB5 was due to both skill and luck:
is an experienced asteroid hunter who just happened to be in the right part of the world to see the object on its way to Earth.
And her efficiency got Scout going.
Within the first hour of making his observations, Sárneczky processed his images, double-checked the object’s coordinates, and sent everything to the Minor Planet Center.
Using 14 observations taken in 40 minutes by a single astronomer, Scout correctly predicted the time and place of 2022 EB5’s encounter with Earth’s atmosphere.
No one was around to see it, but a weather satellite recorded his final moment:
an ephemeral flame quickly consumed at night.
This is not Scout’s first successful prediction.
In 2018, another tiny terrestrial asteroid was discovered 8.5 hours before impact.
Scout correctly identified its trajectory, which proved critical for meteor hunters who found two dozen remaining fragments in the lion-filled Central Kalahari Game Reserve in Botswana.
That won’t be possible for 2022 EB5.
“Unfortunately, it landed in the sea north of Iceland, so we won’t be able to recover the meteorites,” said Paul Chodas, director of the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory.
Chodas said that we also need not worry that this asteroid was detected only two hours before its arrival.
“Small asteroids hit Earth quite frequently, more than once a year for this size,” he said.
And their sizes mean their hits are usually inconsequential.
“Don’t worry about the little things,” Chodas said.
That Scout continues to prove her worth is welcome.
But it will be of little comfort if this program, or NASA’s other near-Earth object monitoring systems, identify a much larger asteroid headed our way, because Earth is currently He has no way to protect himself.
A worldwide effort is underway to change that.
Scientists are studying how nuclear weapons could deflect or annihilate threatening space rocks.
And at the end of this year, the redirect test Double Asteroid, a NASA space mission, will collide with an asteroid in an attempt to change its orbit around the sun, a test for the day when we need to get an asteroid out of Earth’s path for real.
But such efforts will mean nothing if we don’t know the locations of potentially dangerous asteroids.
And in this sense, there are still too many known unknowns.
Although scientists suspect that most of the near-Earth asteroids large enough to cause devastation around the world have been identified, it is possible that a handful still lurk. behind the sun
More worrisome are near-Earth asteroids about 140 meters across, numbering in the tens of thousands.
They can create city-wiping explosions “larger than any nuclear test ever conducted,” said Megan Bruck Syal, a planetary defense researcher at Lawrence Livermore National Laboratory.
And astronomers estimate that they have currently found around the half of them.
Even an asteroid just 150 feet (48 meters) in diameter hitting Earth “is still a really bad day,” Bruck Syal said.
One such rock exploded over Siberia in 1908, leveling 2,000 square kilometers of forest.
“That’s still 1,000 times more energy than the Hiroshima explosion.”
And perhaps only 9% of NEOs in this size range have been detected.
Fortunately, in the coming years, two new telescopes are likely to help with this task: the giant Vera C. Rubin optical observatory in Chile and the space-based Near-Earth Object Surveyor infrared observatory.
Both are sensitive enough to potentially find up to 90% ofe those urban assassins of 140 meters or more.
“As good as our capabilities are right now, we need these next-generation surveys,” Chodas said.
The hope is that time is on our side.
The odds of a city-destroying asteroid hitting Earth are aboutl 1% per century: Low, but not comfortably low.
“We just don’t know when the next impact will happen,” Chodas said.
Will our planetary defense system be fully operational before that dark day arrives?
c.2022 The New York Times Company
