The recently discovered asteroid 2024 YR4 has sparked concern due to preliminary calculations suggesting a small but non-zero chance of impacting Earth in 2032. While the current probability stands at 1.2%, meaning a 98.8% chance of a miss, the possibility warrants further investigation and monitoring.
The Asteroid Terrestrial-impact Last Alert System (ATLAS) initially detected 2024 YR4 on December 27, 2024, at a distance of 515,116 miles (829,000 kilometers) from Earth. Although currently moving away from us, its trajectory indicates a close approach in December 2028.
It’s crucial to understand that the 1-in-83 odds of impact are preliminary and subject to revision as astronomers gather more data. According to NASA’s Jet Propulsion Laboratory’s Center for Near Earth Object Studies (CNEOS), initial impact probability calculations can be inaccurate, sometimes by a significant factor.
Understanding the Potential Threat of 2024 YR4
CNEOS estimates 2024 YR4’s diameter to be around 180 feet (55 meters) and its potential impact speed at 10.76 miles per second (17.32 kilometers/second). Six potential impact events between 2032 and 2074 have been identified, with the highest probability occurring on December 22, 2032. Importantly, the probability diminishes with each subsequent pass, and only the 2032 date currently registers as a Torino Scale 3 risk.
Assessing the Risk on the Torino Scale
The Torino Impact Hazard Scale categorizes the potential danger posed by asteroids. 2024 YR4’s level-three rating indicates a 1% or greater chance of a collision capable of localized destruction, requiring attention from astronomers, especially given its relatively close approach within the next decade. However, CNEOS notes that further telescopic observations are likely to lead to a reassessment and potentially a downgrade to Level 0, indicating no hazard.
Potentially Hazardous Asteroids and 2024 YR4
Potentially Hazardous Asteroids (PHAs) frequently pass through our region of the solar system. Despite their classification, PHAs rarely pose a direct threat to Earth. They are defined by their size, large enough to survive atmospheric entry, and their proximity to Earth’s orbit.
While not large enough to cause a global catastrophe, 2024 YR4 could still unleash significant energy upon impact. NASA estimates a potential impact could release approximately 8 megatons of energy, over 500 times the energy of the Hiroshima atomic bomb and comparable to the 1908 Tunguska event.
Comparing to Apophis: A Previous Asteroid Concern
2024 YR4’s Torino Scale rating is notable, as only one other asteroid, 99942 Apophis, has achieved a higher rating (level 4 in 2004). However, Apophis’s threat level has since been downgraded to zero, with no significant impact risk anticipated for the next century.
Continued Monitoring and Future Implications
The characteristics of 2024 YR4, including its speed, size, and mass, are subject to refinement as scientists continue tracking its trajectory. The situation could evolve, becoming either less or more concerning as the asteroid approaches.
The Importance of Planetary Defense
Continuous monitoring of the skies for potentially hazardous objects is crucial for planetary defense. NASA’s successful DART mission, demonstrating asteroid redirection technology in 2022, highlights the proactive approach to mitigating potential future threats, a capability that hopefully will never be needed, but remains a vital safeguard.
