Asteroid 2024 BX1 spotted three hours before impact

On 20 January 2024, astronomer Krisztián Sárneczky detected an asteroid on an imminent collision course with Earth.Just hours later, it struck our planet’s atmosphere 50 km west of Berlin, producing a stunning fireball.Named '2024 BX1', this is just the eighth asteroid that humankind has spotted before impact – and the third discovered by Sárneczky.

It was at 22:48 CET on Saturday 20 January when veteran asteroid hunter Sárneczky discovered a new asteroid using the 60 cm Schmidt Telescope at Piszkéstető Mountain Station, part of 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.

Sárneczky continued to make and report his observations and was soon joined by others in Europe. More than a dozen observatories turned their eyes towards the incoming object. With their help, it soon became clear that the small asteroid, roughly one metre in size, would impact Earth in less than two hours, approximately 50 km west of Berlin, Germany.

Asteroids of this size strike Earth on average every couple of weeks. They pose no significant danger, and most are never detected. But they can help us understand how many small asteroids are out there and we can study the fireballs they produce to determine what they are made of – if we catch them on camera.

Observers held their breath, but they didn’t have to wait for long. Just a few minutes later, at 01:32 CET, 2024 BX1 struck Earth’s atmosphere and burned an explosive streak through the night sky. Many people in the Berlin area and across central Europe were able to witness the fireball, and a handful of people and automated camera systems even managed to record it.