On January 20, 2024, astronomer Christian Sarnecki discovered an asteroid approaching Earth, which just hours later crashed into our planet’s atmosphere 50 km west of Berlin, creating a fireball. Dubbed “2024 BX1”, it is only the eighth asteroid discovered by humanity before the impact, and the third discovered by Sarnetsky. The asteroid impact created a bright fireball, or bolide, that was visible from as far away as the Czech Republic and may have scattered small meteorites across the ground at the impact site about 37 miles (60 kilometers) west of Berlin.
At 22:48 CET on Saturday, January 20, experienced asteroid hunter Sarnecki discovered a new asteroid using the 60 cm Schmidt telescope at the Piskestetö mountain station, part of the Konkoly Observatory in Hungary. He immediately sent his data on the asteroid’s trajectory to the Minor Planet Center, but with just three initial observations it was impossible to know for sure whether it was on a collision course with Earth. However, Scharnetsky continued to track the asteroid and just minutes later shared four more observations that clearly indicated a 100 percent chance of an imminent impact.
Automated impact monitoring systems around the world, including ESA’s Meerkat, responded to this new data and sprang into action, sending out warnings to astronomers and asteroid experts. The next day, astronomers continued to track asteroid 2024 BX1 until it entered Earth’s shadow and disappeared from view at 01:25 CET.
Asteroids this size hit Earth on average every couple of weeks. They pose no significant threat and most are never detected. But they can help us understand how many small asteroids there are, and we can study the fireballs they produce to determine what they are made of when caught on camera.
Fortunately, large asteroids with a diameter of several kilometers are much easier to detect and are relatively rare. The vast majority of near-Earth asteroids that could cause devastating damage if they hit our planet have already been discovered, and we don’t know of any that could hit our planet for at least the next hundred years.
Visualization of the trajectory and impact of asteroid 2024 BX1 on January 21, 2024 (ESA)
Before this collision with the Earth’s atmosphere, only eight asteroids were discovered. The first of these discoveries occurred in 2008, and four have been discovered in just the last two years. The first asteroid to be discovered and tracked long before impact with our planet was 2008 TC3, which entered our atmosphere and disintegrated over Sudan in October 2008. This 13-foot (4-meter) wide asteroid scattered hundreds of small meteorites above the Earth’s surface in the Nubian Desert. As humanity’s ability to detect smaller space objects continues to improve, this number is likely to grow exponentially in the coming years.
Also, NEO research is becoming more sophisticated and sensitive, with more of these benign objects being detected before entering our atmosphere, providing a real learning curve for NASA’s planetary defense program. Details gathered from such events help the agency develop mitigation strategies in case a large, dangerous object is found on a collision course with our planet in the future.