Asteroid 2024 YR4 was detected at the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile on December 27, 2024. Initial observations provided only limited data on its orbit, but follow-up studies using telescopes worldwide allowed astronomers to better define its trajectory.
By analyzing the asteroid’s motion relative to the background stars, researchers refined its orbital parameters, leading to the current assessment that it has a 1.2% chance of impacting Earth in 2032. The impact probability remains subject to change as additional observations further improve the accuracy of its predicted path.
The asteroid’s estimated diameter is between 40 and 100 m (130 and 330 feet) and is currently about 43.5 million km (27 million miles) from Earth.
Current calculations suggest that around 14:02 UTC (± 10 min) on December 22, 2032, it could pass within approximately 106 200 km (66 000 miles) of Earth. However, uncertainties in its orbit leave the possibility of an impact, with a risk corridor extending from South America across the Atlantic to sub-Saharan Africa. As additional observations refine its trajectory, the impact probability is expected to be reassessed.
2024 YR4 has been classified as level 3 on the Torino Impact Hazard Scale, which ranges from 0 (no risk) to 10 (certain global catastrophe). A level 3 classification indicates a close encounter meriting attention, with a probability of impact that could cause localized damage. Historically, asteroids initially rated at this level have often been downgraded as more data becomes available.
If 2024 YR4 were to collide with Earth, the impact effects would depend on its exact size, composition, and location of entry.
The asteroid has six potential impact events between 2032 and 2074, with the highest probability occurring in December 2032. If it collides with Earth, its impact velocity would be approximately 17 km/s (11 miles/s).
Such an impact could trigger an atmospheric explosion, known as an “airburst,” or form an impact crater if it reaches the ground.
For comparison, the 1908 Tunguska event in Siberia, attributed to an object of similar size (50 to 80 m / 160 to 260 feet), resulted in the destruction of approximately 2 000 km² (770 mi²) of forest.
What would happen if asteroid 2024 YR4 hit the Earth
The asteroid’s potential impact location and composition remain uncertain. However, using the Asteroid Launcher tool, estimates have been made regarding possible consequences of extremely unlikely impact over populated areas.
In the first scenario, the asteroid is assumed to strike California and be composed of stone. The estimated diameter is 60 m (200 feet), with an impact velocity of 17 km/s (11 miles/s) at a 45° angle.
The impact would produce an airburst, detonating approximately 6 km (3.7 miles) above the ground with an energy release equivalent to 9 megatons of TNT. The resulting fireball could span 1.3 km (0.8 miles) in diameter.
The Asteroid Launcher estimates that the impact could result in nearly 20 000 fatalities and generate a 192-decibel shockwave.
Within 5.3 km (3.3 miles) of the impact site, conditions would resemble an EF5 tornado, with winds exceeding 520 km/h. The wind blast alone could cause approximately 700 fatalities.
In the second scenario, all parameters remain unchanged except for the impact location, which is set to New York City to assess the effects in a densely populated area.
An impact in New York City could result in nearly 1 million fatalities from the fireball alone, with over 30 000 additional deaths caused by the wind blast.
The fireball size, shockwave intensity, and airburst effects would remain consistent with the first scenario. According to the asteroid launcher website, an impact of this size happens once in 660 years.
References:
1 2024 YR4 – NASA JPL – Accessed on January 29, 2025
2 2024 YR4 – Earth Impact Risk Summary – CNEOS – Accessed on January 29, 2025
3 Close approach fact sheet for asteroid 2024 YR4 – ESA – January 29, 2025