Last month, an asteroid impacted Earth’s atmosphere just hours after being detected —  somehow, it managed to circumvent impact monitoring systems during its approach to our planet. However, on the bright side, the object measured just 3 feet (1 meter) in diameter and posed very little threat to anything on Earth’s surface. 

This asteroid, designated 2024 UQ, was first discovered on Oct. 22 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey in Hawaii, a network of four telescopes that scan the sky for moving objects that might be space rocks on a collision course with Earth. Two hours later, the asteroid burned up over the Pacific Ocean near California, making it an “imminent impactor.”

The small amount of time between detection and impact means impact monitoring systems, operated by the European Space Agency’s Near-Earth Object Coordination Center, didn’t receive tracking data about the incoming asteroid until after it struck Earth, according to the center’s November 2024 newsletter. 

“ATLAS survey obtained images that included detections of a small object in a high-probability collision course. However, due to the location of the object near the edge of two adjacent fields, the candidate was recognized as a moving object only a few hours later,” ESA wrote in the newsletter.

“By the time the astrometry reached the impact monitoring systems, the impact had already happened.”

ESA’s NEO Coordination Center (NEOCC) says flashes were detected by the National Oceanic and Atmospheric Administration’s GOES weather satellites and the Catalina Sky Survey, a NASA project that uses a series of telescopes to search for asteroids and comets in our celestial neighborhood. These flashes were enough to confirm asteroid 2024 UQ’s impact as well as its trajectory.

According to ESA, the asteroid was the third imminent impactor detected this year. As for the two other asteroids that were been detected within hours of impacting Earth in 2024, the first is known as 2024 BX1. It measured around 3.3 feet wide (1 meter) and burned up harmlessly over Berlin, Germany in January. The other, 2024 RW1, exploded over the Philippines on Sept. 4. 

Multiple people throughout the island nation caught the resultant fireball on video:

Planetary defense efforts that aim to catalog the myriad of space rocks in our neck of the cosmic woods have become a major priority for space agencies worldwide. Aside from the ATLAS survey, Catalina Sky Survey, ESA’s NEOCC and other projects like them, NASA is developing a new infrared telescope known as NEO Surveyor to hunt for potentially threatening near-Earth objects.

But it’s not all just about detection and tracking. Space agencies are testing methods of redirecting incoming asteroids should the need ever arise. In 2022, NASA’s DART mission crashed an impactor into a double asteroid system in an attempt to change its trajectory (the endeavor was a success). China is also developing its own mission to deflect an asteroid by 2030.