At the helm of this year’s end in 2024, the discovery of the small asteroid 2024 YR4 raises concern about a potential collision with Earth in 2032, with the probability now increased by almost double. To address this, the United States National Aeronautics and Space Administration (NASA) is gearing up to utilize the observation capabilities of the powerful James Webb Space Telescope to closely monitor the asteroid and better assess its threat level.
According to NASA, the asteroid 2024 YR4 was first spotted by the Chilean station of the “Asteroid Terrestrial-impact Last Alert System” (ATLAS), funded by the agency, on December 27, 2024, following which the information was relayed to the Minor Planet Center.
The Minor Planet Center serves as the official organization responsible for collecting observational data on minor planets (asteroids and comets) and is led by the International Astronomical Union. ATLAS comprises multiple telescopes scattered across the globe and is managed by the Institute for Astronomy at the University of Hawaii in the United States.
NASA reveals that the width of 2024 YR4 ranges between 130 to 300 feet (40 to 90 meters). It made its appearance on NASA’s Sentry risk list on December 31, 2024, attracting the attention of astronomers. This automated Sentry list includes any near-Earth asteroids with a probability greater than zero of impacting Earth in the future.
As per NASA’s assessment, the probability of asteroid 2024 YR4 colliding with Earth on December 22, 2032, has been revised from the initial 1.3% to 2.3%, nearly doubling. These preliminary evaluation results will be adjusted as observations continue.
Currently, there are no other known large asteroids with a collision probability exceeding 1%. Should an asteroid with a probability surpassing this threshold be identified, NASA is obligated to inform other relevant U.S. government departments involved in planetary defense.
The current size estimation of 2024 YR4 is solely based on data obtained from ground-based telescopes. Hindered by Earth’s atmosphere, these telescopes can only capture sunlight reflections from the asteroid’s surface, suggesting that 2024 YR4 may potentially be larger than originally estimated.
Ground-based telescopes associated with the International Asteroid Warning Network will continue observing 2024 YR4 until April. Subsequently, the asteroid will become too faint to observe. It won’t be until June 2028, when it approaches the Sun again, that these telescopes will be able to observe it once more.
Furthermore, the Webb Space Telescope owned by NASA, unaffected by Earth’s atmosphere, will begin observing 2024 YR4 from March this year to better evaluate its size and likelihood of impacting Earth.
While it is possible that the risk of asteroid 2024 YR4 colliding with Earth may eventually be nullified, similar to many other objects that previously appeared on NASA’s risk list, the collision probability could also continue to rise. The Sentinel webpage of NASA will provide continual updates on the latest data.
In the event of a collision with Earth, a small asteroid of this size like 2024 YR4 could potentially cause regional damage, akin to the Tunguska Event that occurred in Siberia, Russia in 1908.