[Updated on February 21]
[NASA]
This asteroid (130–300 feet / 40–90 meters) now ranks as a Torino Scale Level 3 hazard—rare enough that only four asteroids since 2015 have reached this designation. If it struck, models suggest that the impact would release energy equivalent to roughly eight megatons of TNT—about 500 times the yield of the Hiroshima bomb—potentially devastating an area comparable in size to Washington, D.C.
The asteroid’s story began two days after its closest Earth approach on December 25, 2024, when the ATLAS telescope in Río Hurtado, Chile captured its movement against stationary stars on December 27. This delayed detection—caused by the asteroid’s sunward approach path—initially left its orbital parameters uncertain. Yet astronomers at the Minor Planet Center quickly calculated its potential risk corridor for 2032 within days, leading to its placement at the top of NASA’s Sentry Risk Table and ESA’s Risk List by December 31.
The top ten items in the NASA-created table, as of February 21, are as follows:
| Object | Year Range | Potential Impacts | Impact Probability (cumulative) | Vinfinity (km/s) | H (mag) | Estimated Diameter (km) | Palermo Scale (cum.) | Palermo Scale (max.) |
|---|---|---|---|---|---|---|---|---|
| (2024 YR4) | 2032-2047 | 4 | 3.6e-3 | 13.26 | 24.0 | 0.055 | -1.11 | -1.11 |
| 29075 (1950 DA) | 2880-2880 | 1 | 3.9e-4 | 14.10 | 17.9 | 1.300 | -0.92 | -0.92 |
| 101955 Bennu (1999 RQ36) | 2178-2290 | 157 | 5.7e-4 | 5.99 | 20.6 | 0.490 | -1.40 | -1.59 |
| (2000 SG344) | 2069-2122 | 300 | 2.7e-3 | 1.36 | 24.8 | 0.037 | -2.77 | -3.12 |
| (2008 JL3) | 2027-2122 | 44 | 1.7e-4 | 8.42 | 25.3 | 0.029 | -2.86 | -2.86 |
| (2010 RF12) | 2095-2122 | 70 | 1.0e-1 | 5.10 | 28.4 | 0.007 | -2.97 | -2.97 |
| (2016 WN55) | 2030-2114 | 16 | 1.3e-3 | NaN | 26.4 | 0.017 | -3.02 | -3.04 |
| (2022 PX1) | 2040-2040 | 1 | 3.2e-6 | 35.11 | 22.3 | 0.120 | -3.13 | -3.13 |
| (2005 QK76) | 2030-2059 | 6 | 7.1e-5 | 19.67 | 25.2 | 0.031 | -3.25 | -3.36 |
| (2024 BY15) | 2071-2124 | 331 | 9.4e-3 | NaN | 26.7 | 0.015 | -3.30 | -3.89 |
Since January 2025, over 30 observatories worldwide, including those in Hawaii, New Mexico and South Africa, have been tracking asteroid 2024 YR4. Each new observation refines its trajectory, narrowing the potential impact zone from a continental-scale band to a projected path spanning approximately 700 miles. The asteroid is expected to remain observable until early April 2025, after which it will fade from view until it re-emerges in June 2028.
Orbit prediction and risk modeling
NASA’s asteroid detection network combines four ATLAS telescopes—two in Hawaiʻi (Haleakalā and Mauna Loa), one in Chile (El Sauce Observatory), and one in South Africa (Sutherland Observatory)—with contributions from other observatories worldwide. The NEOWISE mission, a key space‑based component of this network, concluded its science survey on July 31, 2024, with its transmitter turned off on August 8, 2024; the spacecraft reentered Earth’s atmosphere on November 1, 2024. NEOWISE used infrared sensors to detect heat emitted by asteroids, enabling the identification of objects that optical telescopes might miss due to their dark surfaces or proximity to the Sun.
This ground‑space partnership proved critical in December 2024 when ATLAS‑Chile detected asteroid 2024 YR4 on December 27, 2024, two days after its closest approach to Earth. The delay was due to the asteroid’s approach path from the direction of the Sun, which made it difficult to observe before its closest pass. Observations from ATLAS and other facilities, such as South Africa’s SAAO and Chile’s Very Large Telescope, are refining 2024 YR4’s trajectory models daily, though specific details about narrowing the potential 2032 impact zone to approximately 700 miles remain unconfirmed in available sources.
