These are the latest estimates for the size and impact probability of asteroid 2024 YR4 from ESA’s Near-Earth Object Coordination Centre (NEOCC), as of 4 February 2025:
| Asteroid designation | Size (diameter) | Probability of Earth impact | Date of potential Earth impact |
| 2024 YR4 | 40—90 m | 1.6% | 22 December 2032 |
Find out why the impact probability is changing over time, and why it is likely to fall to zero:
Updates
3 Feb:
- The Space Mission Planning Advisory Group (SMPAG) will continue to monitor the situation.
SMPAG coordinates the international response to any asteroid larger than 50 m across with a greater than 1% chance of impacting Earth within the next 50 years. As 2024 YR4 is currently very close to these size and impact probability thresholds, the group has decided to continue monitoring the situation before initiating any further action.
SMPAG will meet again in late April or early May as the asteroid fades from view to re-evaluate the situation, or earlier in the unlikely event that the impact risk increases significantly. Should the asteroid’s estimated diameter remain above 50 m, and the impact probability remain above 1%, SMPAG will issue a recommendation about further action to the United Nations Office for Outer Space Affairs (UNOOSA).
30 Jan:
- The International Asteroid Warning Network (IAWN) has published its Potential Asteroid Impact Notification.
IAWN coordinates world-wide observations of asteroids larger than 10 m with an impact probability greater than 1%. This notification acknowledges that IAWN is now actively coordinating observations of 2024 YR4.
- ESA’s Near-Earth Object Coordination Centre (NEOCC) has published its first Close Approach Fact Sheet on asteroid 2024 YR4.
The NEOCC produces fact sheets on asteroids that will pass Earth in a noteworthy manner. They provide an overview of ESA’s current understanding of the asteroid’s important characteristics and its encounter with Earth.
29 Jan:
Discussion: 2 comments
Why negative observations are not taken into account when publishing probability of impact?
Thanks for the great question, Gianmarco!
Negative observations can be a good way to reduce our uncertainty about an asteroid’s orbit around the Sun.
To conduct negative observations, astronomers look for the asteroid in older pictures of the night sky. If the asteroid doesn’t appear in certain places at certain times, they can rule out some of its possible orbits.
The hope would be to eliminate the few possible orbits that could lead to an Earth impact.
There is a protocol agreed upon by ESA, JPL, the Minor Planet Center (MPC) and the Near-Earth Objects Dynamics Site (NEODyS) that describes under what conditions we can accept a negative observation for use in our risk assessments.
As of writing, no observations of 2024 YR4 have met all of the necessary criteria.
For reference, this is the protocol in question: https://minorplanetcenter.net/media/documentation/negative_observations/VI_Observations_Protocol_3.1.pdf