China Seizes Role as Humanity's Earthly Saviour, Not America

China is developing an early warning system to detect asteroids that could potentially strike Earth. The system will combine a number of ground-based telescopes with a constellation of satellites operating in orbit. The plan to build the system was revealed by Science and Technology Daily, a Chinese government-run media outlet, citing Li Mingtao, chief scientist at the Asteroid Monitoring and Early Warning Research Centre under the China National Space Administration (CNSA). According to Li, no asteroid has been found so far that is known to be on a direct collision course with Earth. The statement was made in a report on 30 June, coinciding with International Asteroid Day established by the United Nations. Li said more than 95% of near-Earth asteroids with a diameter greater than 1 kilometre have been discovered. That size is considered large enough to trigger a global catastrophe. However, scientists have only found about 45% of asteroids measuring around 140 metres. If it struck Earth, an asteroid of that size could destroy an area the size of a small country. “These undiscovered near-Earth asteroids pose the greatest risk. They are numerous, very faint before approaching, and could even suddenly approach from the direction of the Sun,” Li said. “That is why the world is stepping up efforts to strengthen monitoring and early warning capabilities and catalogue these asteroids as soon as possible. We must not underestimate the risk of impact, but we also need not be overly anxious,” he continued. China will select the best locations to build several large-aperture optical telescopes. According to the Science and Technology Daily report, this step will enable the system to conduct wide sky coverage and accurate measurements. The space-based component will help overcome several limitations of Earth-based observatories. Satellites are unaffected by day and night cycles or weather conditions. Orbiting observatories can also detect asteroids moving towards Earth from the direction of the Sun. This is important because asteroids coming from that direction can be difficult to detect by telescopes on Earth. One example is the asteroid that went undetected until it lit up the sky over Chelyabinsk, Russia, in 2013. Once the system detects a potential threat, scientists will calculate the asteroid’s trajectory and the probability of an impact. If the threat is deemed credible and urgent, the authorities will receive a warning. China began recruiting planetary defence researchers last year after the European Space Agency (ESA) said asteroid 2024 YR4, estimated to be up to 90 metres wide, briefly had a 2.2% chance of hitting Earth in 2032. However, scientists later stated the asteroid was highly unlikely to strike Earth. The report also mentioned China has made breakthroughs in developing algorithms to assess asteroid collision risk. Li said the most practical way to deal with an asteroid threat is to use the kinetic impact method. This method involves crashing a spacecraft into the asteroid to alter its trajectory. According to Li, asteroids can also be diverted using lasers, particle beams, or gravitational forces. However, these methods are relatively weak and could take years to have a significant impact on an asteroid’s trajectory.