In a dramatic turn of events, NASA has managed to reduce the impact risk of asteroid 2024 YR4 by half in just 24 hours. Initially, the risk was estimated to be around 3.1%, the highest predicted in history, but it has now been lowered to 1.5%. This significant reduction is a result of astronomers resuming their observations of the asteroid, which was made possible by the darker skies after a week of limited visibility due to the full moon.
The asteroid, with a diameter ranging from 40 to 90 meters, remains at a 3 on the Turin scale, indicating that it still deserves attention from astronomers. The European Space Agency (ESA) has also revised its estimate, dropping the probability of impact from 1.8% to 1.39%. These updates are a clear indication that ongoing observations are crucial in refining our understanding of the asteroid’s trajectory.
Planetary Defense
As NASA notes, “every additional night of observations improves our understanding of where the asteroid could be on December 22, 2032, and underlines the importance of collecting sufficient data so that our planetary defense experts can determine the future risk for Earth.” The agency is hopeful that the probability of impact will continue to decrease as new observations are made in the coming days and weeks.
The latest observations have helped to further limit the uncertainty surrounding the asteroid’s trajectory. As astronomers continue to monitor the asteroid’s movement over time, the region of possible locations will be further reduced. However, for the probability of impact to be reduced to zero, the Earth would need to be completely out of the possible locations of asteroid 2024 YR4 on December 22, 2032.
Interestingly, there is also a small probability, estimated at 0.8%, that the asteroid could impact the Moon. NASA’s current calculations take into account various scenarios, and this possibility, although remote, is still being considered.
It is still under surveillance
Given its size and the higher-than-1% probability of impact within the next 50 years, asteroid 2024 YR4 meets the criteria that have activated two reaction groups endorsed by the UN: the International Asteroid Alert Network (IAWN) and the Space Missions Planning Advisory Group (SMPAG). When the asteroid is out of reach of terrestrial telescopes, the James Webb Space Telescope will take over, measuring its route and providing valuable insights.
The asteroid is expected to make another close pass near our planet in December 2028, although it can be observed from spring that same year. This upcoming event will provide an opportunity to establish the rock’s definitive trajectory, if it hasn’t been done before. As astronomers continue to monitor asteroid 2024 YR4, one thing is clear: ongoing surveillance and research are essential in mitigating potential risks and ensuring the safety of our planet.
