In late December, astronomers made a significant discovery with the Asteroid Terrestrial-Impact Last Alert System (ATLAS) in Chile, spotting a new asteroid named 2024 YR4. This object, measuring approximately 40 to 100 meters in diameter, was primarily observed on December 27, but its closest approach occurred two days earlier, when it was about 800,000 kilometers from Earth—roughly twice the distance to the moon. “It was zooming right by Earth,” noted an astronomer involved in the observation. While such objects are common in our solar system, further assessment was deemed essential to evaluate any potential risks to our planet.
Recent follow-up observations have elevated concerns. On January 27, a monitoring arm of NASA, known as Sentry, increased the potential impact risk of YR4 to an unprecedented level. Current estimates suggest a 1.3 percent chance of a collision with Earth on December 22, 2032, marking a threat level of 3 on the Torino scale, which categorizes impact risk from 1 to 10. Shortly after, the European Space Agency also echoed a similar risk assessment, and the latest update from NASA has raised the potential impact risk to 1.6 percent.
Despite the low chances of an impact, experts have pointed out that a collision, though unlikely, could still be catastrophic. “There is a 99 percent probability that this is going to miss, and that’s what we expect to happen,” stated a scientist at NASA. However, this is still a higher risk level than that posed by any asteroid since Apophis, which was assessed to have a 2.7 percent chance of impacting Earth in 2029.
If 2024 YR4 were to strike, the consequences would be significant. According to experts, the impact force would be equivalent to a “10-megaton bomb,” enough to cause severe regional destruction. “Everything within three or four kilometers would be incinerated,” an astronomer explained, highlighting the peril of such an event.
Observations have indicated that YR4 is a stony asteroid, which could lead to an atmospheric explosion rather than a surface impact, similar to the historic Tunguska event in 1908. Recent incidents, like the 2013 Chelyabinsk meteor explosion, showcase the potential damage even smaller asteroids can cause.
Concerned about YR4’s trajectory, astronomers have already begun to map potential impact corridors, predicting areas that could be at risk based on the asteroid’s projected path. The potential corridors largely cover regions from the Pacific Ocean through South America, up to portions of Africa and Asia.
Despite the seemingly distant timeline, experts stress the importance of tracking this asteroid as the odds can swiftly change. The Torino scale could either diminish as astronomers refine their observations or potentially reveal a tighter trajectory toward Earth, increasing the urgency to prepare for a deflection mission.
Astronomers are moving rapidly to monitor YR4 as they have a narrow window of visibility before it becomes obscured later this year. The next opportunity to observe the asteroid won’t come until 2028, which leaves little time to devise an effective response should the potential for an impact remain. Discussions for possible mitigation or evacuation strategies are likely to take center stage during upcoming meetings of international space agencies.
In a time of uncertainty, the collaborative global approach to tracking and studying potential asteroid threats demonstrates progress. As astronomers continue their efforts to monitor and evaluate risks, advancements in technology make tasks like detecting objects like YR4 exponentially more achievable, ensuring that our planet is better safeguarded against celestial threats.
