In the distant future, the earth will be hit by an inevitable large meteorite from space, just like the rising and setting of the sun and the ebb and flow of the tides. This has happened many times in the past, and it will be the same in the next billion years.
Human beings are lucky now that they don’t have to face global catastrophic threats, but if they want to survive on Earth for a long time, they must accept the reality of dangerous asteroids and be prepared. Organizations around the world continue to monitor the skies and catalog all potentially threatening NEOs. Larger rocks, while certainly more threatening, are relatively few in number. The number of potentially hazardous near-Earth objects can never be exhausted, but now we have reliable and useful maps of almost all potentially hazardous asteroids larger than 1 kilometer in diameter.
Kilometer-level asteroids may not only destroy entire cities, but may even cause a major global ecological crisis. A team predicts that asteroids will orbit within a thousand years, and that kilometer-level near-Earth objects will not pose a major threat to the earth until the next century.
Although it is difficult to predict the orbital changes of near-Earth objects, because orbital dynamics indicate that small changes may have a huge impact over time, whether “receiving heat from the sun” or “Jupiter’s gravitational pull” may make an asteroid The orbit will rendezvous with the Earth after a thousand years.
Asteroid 7482 is particularly dangerous. It will linger near the earth for a long time within a thousand years. Although it does not mean that it is very likely to hit the earth, the probability is not zero; the orbit of asteroid 143651 is very chaotic, and there is no way to predict it perfectly in the past few decades. The exact location, based on the information currently available, is uncertain whether it will hit the earth in the future.
Scientists have found 28 similar celestial bodies, all of which may be within the distance of the earth and the moon. Although the millennium orbit predicts that the chance of impacting the earth is not high, long-term attention to these large rocks may be more important than anything else. Papers can be downloaded from the preprint website.
▲ Orbit map of known potentially threatening asteroids (more than 140 meters in size and passing Earth’s orbit within a distance of 7.6×10⁶km (4.7×10⁶mi)) in 2013. (Source: NASA/JPL-Caltech, Public domain, via Wikimedia Commons)
(This article is reproduced with the authorization of Taipei Planetarium; Source of the first image: NASA)
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