Chinese scientists say 2% probability of asteroid hitting Earth

Chinese scientists have been monitoring an asteroid since early January 2025, which may pose a collision risk with Earth in 2032. Their calculations estimate a 2 percent chance of impact.

Zhao Haibin, director of the Planetary Science and Deep Space Exploration Department at the Purple Mountain Observatory of the Chinese Academy of Sciences, reassured the public, stating that as more data is collected, the asteroid's orbit will be better understood, potentially changing the impact probability. He emphasized there's no immediate cause for concern and urged the public to wait for further updates from astronomers.

The asteroid, named 2024 YR4, is estimated to be between 40 and 90 meters in diameter, roughly the size of a large building. It was discovered on December 27, 2024, by the ATLAS telescope in Chile. NASA's Sentry system previously estimated a 2.1 percent chance of impact, while the European Space Agency's (ESA) system calculated a 2.02 percent probability.

Zhao explained that the asteroid's orbit is primarily calculated through optical observations. As the asteroid reflects sunlight, telescopes track its movement relative to nearby stars, allowing astronomers to calculate its trajectory. The asteroid has a relatively high orbital eccentricity, meaning its path is elliptical, and it crosses near Earth's orbit roughly every four years. The current period and the one in 2028 are ideal observation windows.

Although current technology doesn't allow for direct interception of asteroids, experts believe it may be possible to slightly alter its trajectory. Methods to prevent an asteroid impact include launching rockets to redirect it or evacuating affected areas.

An anonymous scientist noted that a large asteroid, with a diameter exceeding 1,000 kilometers, could cause catastrophic damage, while one around 10 kilometers in diameter could lead to mass extinction. However, a smaller asteroid, about 50 meters in diameter, could devastate thousands of square kilometers, equivalent to a major city. Zhao reassured the public, emphasizing that with ongoing asteroid monitoring, a response plan would be developed if needed.

The International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG), active since 2013, work together to monitor and issue warnings about potentially hazardous asteroids. If an asteroid with a 1 percent or greater chance of impact is identified, these groups issue warnings, coordinate observations, and may activate defense measures if necessary.

At a 2018 conference in Beijing, Chinese scientists discussed asteroid monitoring, early warning systems, and defense strategies. Experts highlighted that if an asteroid the size of 50 meters poses a risk, measures should begin 3 to 4 years in advance.

China has made significant strides in asteroid detection and monitoring, with the Near-Earth Object Telescope at Purple Mountain Observatory and the Wide Field Survey Telescope contributing valuable findings. To date, over 60 near-Earth asteroids have been discovered by China, reflecting the nation's commitment to asteroid monitoring, early warning, and defense.