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Close encounter: Truck-sized asteroid will buzz Earth Thursday in one of nearest near-misses ever

Space rock will zoom by Earth in one of the closest encounters ever

SHARE Close encounter: Truck-sized asteroid will buzz Earth Thursday in one of nearest near-misses ever
This NASA diagram shows the estimated trajectory of asteroid 2023 BU, in red, affected by the earth’s gravity.

This diagram made available by NASA shows the estimated trajectory of asteroid 2023 BU, in red, affected by the earth’s gravity, and the orbit of geosynchronous satellites, in green. On Wednesday, Jan. 25, 2023, NASA revealed that this newly discovered asteroid, about the size of a truck, will zoom 2,200 miles above the southern tip of South America Thursday evening. Scientists say there is no risk of an impact. Even if it came a lot closer, scientists say it would burn up in the atmosphere, with only a few small pieces reaching the surface.

NASA via Associated Press

NASA’s Jet Propulsion Laboratory says an asteroid the size of a box truck will fly over the southern tip of South America on Thursday evening at about 2,200 miles above the surface in one of the closest approaches ever recorded of a near-Earth object.

JPL scientists say there is no risk of the asteroid impacting Earth. But even if it did, this small asteroid — estimated to be 11.5 to 28 feet across — would turn into a fireball and largely disintegrate harmlessly in the atmosphere, with some of the bigger debris potentially falling as small meteorites.

The asteroid, designated 2023 BU, was discovered by amateur astronomer Gennadiy Borisov, discoverer of the interstellar comet 2I/Borisov, from his MARGO observatory in Nauchnyi, Crimea, on Jan. 21. JPL said additional observations were reported to the Minor Planet Center, the internationally recognized clearinghouse for the position measurements of small celestial bodies, and the data was then automatically posted to the Near-Earth Object Confirmation Page

JPL reports the asteroid will be closest to Earth at about 5:27 p.m. MST Thursday, only 2,200 miles above the planet’s surface and well within the orbit of geosynchronous satellites.

NASA’s Scout impact hazard assessment system, which is maintained by the Center for Near Earth Object Studies at the agency’s Jet Propulsion Laboratory in Southern California, analyzed the data from the Minor Planet Center’s confirmation page and quickly predicted the near miss. The Center for Near Earth Object studies calculates every known near-Earth asteroid orbit to provide assessments of potential impact hazards in support of NASA’s Planetary Defense Coordination Office.

“Scout quickly ruled out 2023 BU as an impactor, but despite the very few observations, it was nonetheless able to predict that the asteroid would make an extraordinarily close approach with Earth,” Davide Farnocchia, a navigation engineer at JPL who developed Scout, said in a press release. “In fact, this is one of the closest approaches by a known near-Earth object ever recorded.”

As 2023 BU whisks by Earth, NASA continues to assess data from a September mission that successfully crashed a spaceship into an asteroid in a test of its ability to divert a future space rock on a collision course with Terra Prime.

Sponsored by NASA’s Planetary Defense Coordination Office and led by the Johns Hopkins University Applied Physics Laboratory, the Double Asteroid Redirection Test, or DART, was a $325 million project designed to crash the 1,260-pound spacecraft traveling at 14,000 mph into Dimorphos, an asteroid that’s 525 feet in diameter and 7 million miles from Earth.

Dimorphos is a moonlet asteroid, orbiting a larger asteroid named Didymos, which is about a half-mile in diameter. Mission officials have stressed that the binary system “is not on a path to collide with Earth and therefore poses no actual threat to the planet” but is the “perfect testing ground” to see if an asteroid’s natural path can be altered via a high-velocity impact.

About a month after the collision, NASA confirmed that the impact had changed the time it takes Dimorphous to make one revolution around Didymos from 11 hours and 55 minutes to 11 hours and 23 minutes — a difference of 32 minutes.

Thanks to an onboard camera system that streamed at one-image-per-second back to Earth, mission engineers, along with the viewing public, had a real-time view, albeit one delayed by the 45 seconds or so that it takes for the video to process and stream back to Earth-based receivers, capturing DART’s approach and collision with Dimorphos.

Right now, no known asteroid larger than 140 meters in size has a significant chance to hit Earth for the next 100 years, but only about 40% of those asteroids have been found as of October 2021, according to NASA.