An asteroid, 2024 YR4, received an unusually high impact probability in January 2025, sparking concerns among the public. As a planetary defense expert, I was initially asked to explain what this meant for Earth’s safety.
Scientists monitor asteroids whose trajectories may take them close to our planet and calculate their likelihood of collision using observational data and mathematical models. However, simply having more data points doesn’t necessarily make predictions better; they need continued monitoring as the asteroid moves through space.
Upon further observation, the impact probability decreased significantly over time, from 3.1% on February 18th to less than 0.0000081% by June 15th. Yet, the likelihood of the asteroid hitting the Moon increased, posing a potential threat through ejected materials that could reach Earth’s atmosphere.
A key aspect of assessing an impact threat is understanding the orbital uncertainty surrounding an asteroid. When there is limited observational data, the error ellipse – which represents possible orbits – can be large, increasing the chance that it may accidentally include our planet.
As scientists continue to refine their predictions, it’s essential to consider how best to communicate these results to the public. Simply using the impact probability without context can be misleading, as seen with 2024 YR4. Alternative approaches, such as refining collision predictions or introducing new metrics, could provide more actionable guidance for future threats.
This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world.
Source: https://www.fayettenewspapers.com/premium/theconversation/stories/how-do-scientists-calculate-the-probability-that-an-asteroid-could-hit-earth,147426