Experts believe that asteroids larger than 1 kilometer in diameter and comets exceeding 600 meters pose a potential threat to Earth. Currently, there are approximately 1,200 to 2,000 asteroids of 1 kilometer in diameter in the cosmos, while the solar system contains as many as 1 million comets with a diameter of 100 meters. Although the probability of an asteroid impacting Earth is low, it is not entirely out of reach.
The chance of Earth experiencing an asteroid impact each year is only 1 in 500,000. Over the next 100 years, this probability increases to 1 in 100,000. For an individual, the likelihood of encountering an asteroid impact in their lifetime is about 1 in 200,000. Historically, significant collision events occur every 10 to 80 million years.
Japanese astronomer Makoto Yoshikawa has indicated through research that the probability of an asteroid larger than 1 kilometer impacting Earth is approximately once every 120,000 years. Over the next 2,600 years, five or six asteroids will approach Earth, with the closest passing at a distance of 150,000 kilometers, which is half the distance from the Earth to the Moon.
In light of this potential threat, astronomers are calling for increased public awareness and suggest early forecasting and trajectory calculations. Chinese astronomers have released important information through the media: over the next 100 years, Earth will experience three close encounters with asteroids. The first occurred on September 29, 2004, when asteroid 4179 passed 1.5 million kilometers from Earth; the second is expected in 2069 when asteroid 2340 will pass 1 million kilometers away; and the third will occur in 2086, when an asteroid will again approach Earth at a distance of 1.05 to 1.1 million kilometers.
