Asteroid 2024 YR4, which could devastate a city’s worth of humans, has gone from 1.2% to 2.3% to 2.6% to 3.1% chances of impact. Here’s why.
On December 27, 2024, a very small, fast-moving asteroid was found in the vicinity of Earth. Dubbed 2024 YR4, or YR4 for short, it’s approximately 50 meters in diameter, weighs somewhere around 200,000 tons, and made its most recent, closest approach to Earth just two days prior: on December 25, 2024. In the time since its discovery, many observatories have monitored its motion, enabling us to reconstruct its orbit to a fairly good level of precision. We know it orbits the Sun with a period of around 4 years, achieving a maximum distance from the Sun of around 4.18 astronomical units, or right at the outer edge of the asteroid belt. It will make its next close approach to Earth (but will definitively miss us) on December 17, 2028, and then have a second, potentially hazardous encounter with us four years later: on December 22, 2032.
The best data we have indicates that the asteroid will miss us in 2032 by a slim margin: just 160,000 kilometers, or less than half of the distance from the Earth to the Moon. However, our data is still highly uncertain, with a (99.7%…
