A small asteroid caught scientists by surprise after going undetected until just hours before it struck Earth. According to the European Space Agency’s Near-Earth Object Coordination Center, the asteroid, now designated as 2024 UQ, was first observed by the ATLAS survey on the morning of Oct. 22.
The agency’s November newsletter announced the discovery of 2024 UQ which they say is the tenth known “imminent impactor” and the third such object detected in 2024 alone.
However, the circumstances surrounding its detection were unusual.
“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,” the newsletter reads.
With the late detection, by the time the asteroid’s trajectory data had reached monitoring systems, it had already collided with Earth. Scientists said the impact was confirmed through “prediscovery detections” by the Catalina Sky Survey in Arizona, and a flash signal detected through a series of weather satellites, known as the GOES meteorological satellite.
The combined results allowed scientists to map out the asteroid’s trajectory, where they discovered it had entered Earth’s atmosphere over the Pacific Ocean.
According to the newsletter, the incident underscores a need for improvements in near-Earth object (NEO) detecting systems. October also proved to be an active month for NEO discoveries, with the center reporting more than 450 new detections. As of the latest count, there are 36,336 known near-Earth asteroids and 122 comets, with 1,694 objects currently on the risk list.
The month of October also saw two notable close approaches. According to the newsletter, asteroid 2024 UG9, measuring around 1 to 2 meters in diameter, passed Earth within about 8,850 kilometers of Earth’s center on Oct. 30. This makes it “the third-closest non-impacting asteroid fly-by ever observed.”
Earlier that month, asteroid 2024 TH11 came within about 30,000 kilometers of Earth’s center on Oct. 10. With an estimated diameter of about 10 to 20 meters, the asteroid reached a visual magnitude of almost 10, making it unusually bright for an asteroid of its size, scientists said.
Upcoming near-Earth passes include asteroid 2006 WB, a well-known asteroid about 100 meters in diameter that is expected to pass within 2.3 lunar distances of Earth on Nov. 26.
The recent events highlight the ongoing efforts worldwide to strengthen the planet’s defenses, according to the newsletter.
The successful launch of the agency’s Hera mission on Oct. 7 represents a significant step forward, scientists said.
“All systems are working nominally” for Hera, which is now en route to a Mars flyby scheduled for March 2025.