A small asteroid measuring approximately 3 feet (1 meter) disintegrated safely over Germany at 1:32 a.m. Central European Time (CET) on Sunday, January 21. NASA’s Scout impact assessment system, which tracks data on potential asteroid discoveries, gave early warning of where and when the asteroid would hit, ninety-five minutes before it hit Earth’s atmosphere. This is the eighth time in history that a small asteroid approaching Earth has been detected in space before entering our atmosphere and disintegrating.

The asteroid’s impact produced a bright fireball, or bolite, that was visible as far away as the Czech Republic and may have scattered small meteors onto the ground at the impact site about 37 miles (60 kilometers) west of Berlin. The asteroid was later named 2024 BX1.

While NASA reports near-Earth objects (NEOs) of all sizes, Congress has authorized the agency to detect and track NEOs 140 meters and larger that could cause serious harm to Earth if they impact our planet. These objects can be detected much earlier than smaller objects such as 2024 BX1.

Small asteroids like this occasionally hit our planet. These pose no threat to life on Earth, but could be a useful indicator of NASA’s planetary defense capabilities, such as Scout’s rapid-response orbit calculation and collision warning.

as predicted

Asteroid 2024 BX1 was first observed less than three hours before impact by Krysztian Sarnecki of the Konkoli Observatory’s Piszkestete Mountain Station near Budapest, Hungary. These initial observations were reported to the Minor Planet Center, an internationally recognized knowledge base for measuring the position of small objects in the Solar System, and were automatically published on the center’s near-Earth object confirmation page so other astronomers could make additional observations.

Developed and operated by the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Southern California, Scout automatically retrieved new data from this page and revealed the object’s likely trajectory and likelihood of impacting Earth. CNEOS calculates the orbit of each known NEO to provide an estimate of the potential collision hazard for the Planetary Defense Coordination Office (PDCO) at NASA Headquarters in Washington.

With three observations posted within 27 minutes on the confirmation page, Scout initially determined that an impact was possible and that additional observations were urgently needed. As astronomers across Europe reported new data to the Minor Planet Center, the asteroid’s orbit became better known and the likelihood of a collision with Earth increased significantly.

Seventy minutes after initial detection of 2024 BX1, Scout reported a 100% chance of colliding with Earth and began narrowing down location and time. As tracking continued and more data became available over the next hour, Scout improved its time and location estimates. As the asteroid disintegrated in a relatively populated part of the world, many photos and videos of the fireball were posted online within minutes of the event.

NEO Tracking

The first asteroid to be detected and tracked long before it hit our planet was 2008 TC3, which entered our atmosphere and disintegrated over Sudan in October 2008. This 13-foot-wide (4 meters) asteroid scattered hundreds of small meteorites across the Nubian Desert.

In early 2023, another small asteroid called 2023 CX1 was detected over northwestern France seven hours before entering the Earth’s atmosphere. Scout accurately predicted the location and time of impact, as did the 2024 BX1.

As NEO studies become increasingly complex and sensitive, more of these harmless objects are being detected before they enter our atmosphere, providing real application for NASA’s planetary protection program. Details collected during such events help inform the agency’s mitigation strategies in the event a large, dangerous object is detected heading toward our planet in the future.