Impact Imminent: Racing To Track Asteroid 2024 BX1’s Collision Course With Earth

• On January 20, 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.

Discovery of Asteroid 2024 BX1

It was at 22:48 CET on Saturday, January 20 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.

However, Sárneczky continued tracking the asteroid, and just a few minutes later, he shared four more observations that clearly indicated a 100 % chance of an imminent impact.

The final detection of asteroid 2024 BX1 (initially known as Sar2736 prior to impact) obtained by Luca Buzzi from the Schiaparelli Observatory in Italy. The exposure was started at 00:24:55 UTC on January 20, 2024. The asteroid is traveling from the center of the image towards the top and begins to fade from view as it enters Earth’s shadow. Credit: L. Buzzi, G. V. Schiaparelli Observatory

Global Response and Impact

Automatic impact monitoring systems around the world, including ESA’s ‘Meerkat’, responded to these new data and sprang into action, issuing an alert to astronomers and asteroid experts.

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

Predicted impact location and time computed by ESA’s imminent impactor alert system “Meerkat” following the first 14 observations of the object Sar2736 (later designated asteroid 2024 BX1). Meerkat updates assessments each time it receives new observations. Credit: ESA, CC BY-SA 3.0 IGO

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.

Thankfully, large asteroids that are many kilometers in diameter are much easier to spot and relatively rare. The vast majority of near-Earth asteroids that would cause devastating damage if they were to impact our planet have already been spotted, and we know of none that will collide with our planet for at least the next one hundred years.

ESA’s Gaia spacecraft maps 150,000+ asteroid orbits. Credit: ESA/Gaia/DPAC, CC BY-SA 3.0 IGO, Acknowledgments: Stefan Jordan, Toni Sagristà, Paolo Tanga; Gaia Sky (developed by Toni Sagristà); Gaia DR3 data (https://www.archives.esac.esa.int/gaia)

The Event and Its Significance

As Saturday night became Sunday morning, astronomers continued to track asteroid 2024 BX1 until, at 01:25 CET, it entered Earth’s shadow and disappeared from view.

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.

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In the late evening of January 20, 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 this stunning fireball at 01:32 CET, Sunday, January 21. Later named 2024 BX1, this is just the eighth asteroid that humankind has spotted before impact. Thanks to the rapid response and information sharing from Earth’s asteroid and fireball communities, including ESA’s Near-Earth Object Coordination Centre, many people were able to see and record this spectacular sight, despite it taking place with just hours’ notice and in the middle of the night. This video was captured by the AllSky7 network. Credit: ALLSKY7 / Sirko Molau – AMS16 Ketzuer

Only eight asteroids have ever been detected before impact with Earth’s atmosphere. The first of these discoveries took place in 2008, and four were detected in just the last two years. As humankind’s ability to detect smaller space objects continues to improve, this number is likely to rise exponentially in the coming years.

During the three hours between detection and impact, around 180 observations were submitted to the Minor Planet Center, including those of ESA’s Near-Earth Object Coordination Centre taken from Tenerife, Spain.

Visualization of the trajectory and impact of asteroid 2024 BX1 on January 21, 2024, created using the Flyby Visualization Tool of ESA’s Near Earth Object Coordination Centre. Credit: ESA, CC BY-SA 3.0 IGO

Thanks to the rapid response and information sharing from Earth’s asteroid and fireball communities, many people were able to see and record this spectacular sight, despite it taking place with just hours’ notice and in the middle of the night.

The hunt is now on for any potential meteorites that survived the fiery journey through the atmosphere and made it to the ground.

For more on this story, see Small Asteroid Detected on an Imminent Collision Course With Earth.