Just hours after its chance discovery earlier this month, a small asteroid exploded in a ball of fire above the Arctic Sea.
But the short time between the discovery of the space rock known as 2022 EB5 and its impact on Earth doesn’t worry scientists.
Asteroids the size of 2022 EB5, around two to three meters in diameter, pose no threat to people on the ground, and the rapid delay between spotting the asteroid and predicting its impact is a sign that planetary defense systems are working well.
“It shows that in a short period of time we can collect enough data, we can calculate the right trajectory and predict the right impact location,” said Davide Farnocchia, navigation engineer at the Jet Propulsion Laboratory and the Center for Near Earth Object Studies. , where it helps calculate the trajectories of asteroids and comets in the solar system.
“That’s really good news,” he said, and exactly what he hoped would happen in the event of a larger asteroid posing a risk to Earth; larger asteroids are easier to detect earlier, giving policymakers time to act if a space rock threatens Earth.
And scientists have put a lot of effort into searching for asteroids that could pose a threat, especially since Nasa established its Planetary Defense Coordination Office in 2016, though the search for potentially dangerous objects has continued ever since. long time.
In 2005, the United States passed a law requiring NASA to find, analyze and catalog more than 90% of asteroids measuring a kilometer in diameter or larger, the size at which a space rock poses a global risk to Earth.
“That was the biggest risk and that goal has been met, we now have about 95% of those objects in the catalog, and none of them pose a threat for the foreseeable future,” Dr Farnocchia said.
“The next goal is to achieve the same 90% for objects over 140 meters, which aren’t necessarily going to cause global devastation, but they could still cause significant damage.”
According to Dr Farnocchia, several active research programs are looking for potentially dangerous “near-earth objects”, many of which are funded by NASA’s Planetary Defense Coordination Office, but anyone pointing a telescope skyward is a potential sentry.
“They might be looking at galaxies or that sort of thing,” he said, “but they might be spotting asteroids as they do that.”
Observers report newly discovered candidate asteroids to the Minor Planet Center, which posts initial information on a confirmation page, “where they basically put all new candidate objects,” Dr. Farnocchia said, “and they wait for enough data to ensure that the object is real.”
On March 11, Hungarian astronomer Krisztián Sárneczky made the first sighting of what the Minor Planet Center would call 2022 EB5, and based on the Minor Planet Center publication, amateur and professional astronomers trained their instruments on the candidate object to confirm Dr. Sárneczky’s discovery.
The additional data was fed into special software from the European Space Agency and the Nasa, Meerkat and Scout systems, respectively.
“The Sort software automatically picked up the data, started calculating the numbers and determining possible trajectories, projecting the object into the future to see if it could hit. [Earth]said Dr. Fanoccchia. “That probability was 100 percent.”
An asteroid large enough to threaten Earth would be visible earlier than 2002 EB5, he said, so scientists knew it posed little threat. But in a situation where a larger asteroid threatens Earth, the next step would be to determine what mitigation efforts are appropriate.
“You might want to try deflecting it,” Dr. Farnocchia said. “Or if the object is quite small and there’s no time for deflection, you might want to try pushing people out of the way.”
NASA is investigating several approaches to deflect asteroids or dangerous comments, including using a spacecraft flying close to the object over time to slowly pull the object into a different orbit by mutual gravitational attraction, and the use of nuclear detonations or kinetic impacts to push the object off course.
Nasa’s Deep Impact mission in 2005 successfully hit a comet with an impactor, primarily as a way to study the comet’s interior, but Dr Farnocchia presents it as a proof of concept that a space mission can hit successfully a remote object.
And in September, NASA’s Double Asteroid Redirection Test, or DART, will launch a kinetic impactor at the minor planet Dimorphos that will attempt to change its orbit. Nor is Dimorphos’ current orbit, if DART is successful, its new orbit will put it on a collision course with Earth.
Objects like 2022 EB5, meanwhile, hit Earth all the time, “Maybe once a year or so on average,” said Dr Farnocchia, part of the roughly 100 tons of material that hit Earth every day. .
But while it’s common for smaller objects to hit Earth, spotting them before they do is not: 2022 EB5 is only the fifth asteroid detected before hitting our planet, the result of a better and wider observation network rather than a lack of candidate asteroids.
“When you find them, it’s actually a really good exercise for the whole system,” Dr. Farnocchia said. “Can you recognize that the object is on an impact trajectory? And can you predict the location of the impact?”
In the case of 2022 EB5, automatic warning systems such as Meerkat and Scout worked flawlessly, pinpointing almost the exact spot where the space rock would erupt in the air above the sea near the Norwegian island of Jan Mayen.
“From my perspective, it was really impressive that we were able to turn things around in just two hours, two hours from first detection to impact,” Dr Farnocchia said. “Scout worked perfectly automatically. I was just keeping things but didn’t really need to touch anything and was getting updated estimates of where the impact was.
Going forward, the rapid move from discovery to impact prediction for 2002 EB5 should reassure people, Dr. Farnocchia said, that so much searching of the sky is going on, looking for objects dangerous and non-dangerous.
“Find them before they find us,” he said, “that’s the rule of the game.”