nThe true end of civilization may not come from war, but from celestial visitors. Approximately 66 million years ago, an asteroid with a diameter of about 10 to 15 kilometers struck what is now the Yucatán Peninsula in Mexico, leaving behind the Chicxulub crater. The energy released by this impact far exceeded the combined power of all human nuclear weapons. The subsequent global cooling and ecological collapse led to the extinction of about 75% of species, marking the end of the dinosaurs. This is not mythology, but a fact confirmed by geological and chemical evidence.n
nIf an impact of similar magnitude were to occur today, humanity would not vanish instantly, but civilization would face unprecedented disruption. The immediate impact would depend on the location. An impact on land near densely populated areas could cause shockwaves, extreme heat, and massive fires, killing tens of millions or even hundreds of millions within hours. If it struck the deep sea, coastal regions might be hit by colossal tsunamis. Regardless of the impact site, the true determinant of human fate would not be the first day, but the ensuing years.n
nThe scientific community has conducted extensive simulations on the so-called ‘impact winter.’ Dust and sulfuric aerosols would enter the stratosphere, blocking sunlight, causing surface temperatures to plummet, and severely weakening photosynthesis. Modern society heavily relies on stable agriculture and global supply chains. If major grain-producing regions suffered consecutive years of reduced yields, global food reserves would quickly deplete, and energy and transportation systems would be disrupted, turning food into a matter of survival rather than just a pricing issue. With today’s population of approximately 8 billion, in extreme scenarios, the death toll could likely reach billions, not just millions or tens of millions.n
nThere is no precise academic figure, as too many variables exist. The impact location, season, angle of entry, and level of international cooperation would all alter the outcome. However, climate models and ecological inferences suggest this would be a near-global systemic collapse. Some populations might survive in underground facilities, remote areas, or countries with high reserves, but it would be a world with drastically reduced populations and regressed technological levels.n
nIt is important to emphasize that such impacts are extremely low-probability events. The frequency of a 10-kilometer-diameter asteroid striking Earth is about once every tens of millions to hundreds of millions of years. Humanity has not existed long enough to naturally encounter one. However, low probability is not zero probability. NASA and the European Space Agency have been monitoring near-Earth objects and have successfully tested asteroid deflection technologies in recent years. These efforts may not change the randomness of the cosmos, but they at least show that humanity is beginning to proactively respond.n
nDiscussing such disasters can easily lead to doomsday sentiments. What truly merits reflection is the resilience of civilization. When food, energy, and order are simultaneously under pressure, can society still maintain cooperation and rationality? When the dinosaurs went extinct, there was no civilization to collapse. If a similar-scale event were to occur today, humanity would face not only an astrophysical problem but a test of institutional and coordination capabilities.n
nThe sky does not target humanity, but it will not show mercy either. If a Chicxulub-level impact were to recur, deaths could reach billions, and survivors would face a prolonged winter. The future of civilization depends not only on celestial orbits but also on whether we are willing to remain vigilant and prepared for the enormous risks of extremely low probability.n
