Lead
"On May 27, 2022, an asteroid of more than 50 meters passed by the Earth at a speed of 76,000 kilometers per hour for long-distance observation."
This news is not good news, 30 years have passed, and people's memories of this asteroid seem to have been lost in the long river of time.
But the asteroid has always posed a potential threat to human civilization.
The asteroid was called one of the most devastating threats of the year by NASA.
So what exactly is this asteroid?
1. I've been here for 33 years.
The asteroid's name is 7335 (1989JA) and is known to many as the asteroid 1989JA.
Asteroid 1989JA was discovered in 1989 by a Chinese astronomical employee of the Xi'an Astronomical Institute and reported to the Minor Planet Center.
Although the international conditions were relatively backward at that time, and many researchers had made remarkable progress in discovering new planets and comets, most of the asteroids were still observed and discovered by developed countries.
Therefore, after the discovery of the asteroid in 1989, it immediately attracted the attention of many astronomical research centers around the world.
After the asteroid 1989JA was observed, it became a "short-period comet" due to its close orbit and short period of the original Earth, which is why it was later considered a great threat.
Short-period comets actually refer to celestial bodies with a short orbital period and the sun as the center of the sun, unlike our common comets, which twinkle and shiny, the discovery of short-period comets is often accompanied by more surprising events, such as Halley's comet.
1989JA was not observed during its first passby because its orbit was close to the Sun and therefore could not be observed by telescopes in the night sky.
However, this shortcoming is not good to continue, as the asteroid 1989JA is much more threatening than many comets, not as small as Halley's comet, but an asteroid with a diameter of 1.8 kilometers.
Although the 1.8-kilometer radius doesn't seem particularly scary compared to buildings on Earth, the great threat of this asteroid is the power of its impact.
A smaller radius means less kinetic energy when increasing velocity, so the threat of asteroid 1989JA does not come from its size, but from its speed in space.
In fact, the speed at which asteroid 1989JA contacts the Earth is 76,000 kilometers per hour, and at this speed, even human spacecraft cannot stop it, which can be said to invisibly increase the threat value of asteroid 1989JA.
Asteroid 1989JA has not been seen in human vision since a close pass to Earth.
Although the asteroid was observed and its orbit was calculated more accurately, the asteroid was not observed to pass again, so the asteroid was not noticed by too many people.
This situation has continued until 2022, which means that 33 years have passed since 1989JA left in 2022.
The period of the asteroid 1989JA is not long, as its circumference is 33 years.
Therefore, from 1989, the time when it will reach Earth again is 2022.
Many people also think, so what?
Current technology has advanced to such an advanced level that even if the asteroid's orbit shifts a little, it can be orbitally corrected to ensure that it is forever away from Earth.
But even though the asteroid 1989JA is so close to Earth that even Copernicus could have observed it compared to an asteroid with a radius close to Earth in the solar system, it is still millions of kilometers away.
For such asteroids, which take time to discover, the observation equipment on Earth is somewhat powerless.
2. Eternal danger.
Although the asteroid 1989JA has a cycle of only 33 years, this does not mean that it threatens the Earth only once, on the contrary, it is precisely because of its short period that such an asteroid is more dangerous for the Earth.
In the asteroid cycle, it can be seen as a permanent threat, as in antiquity, as in antiquity, as a great danger, and this assumption is correct.
Because it is an eternal threat, one may focus on how much it currently threatens the planet when observing its passage, but this view is actually relatively short-sighted.
Because the speed of the threat is 76,000 kilometers per hour, if you look at its speed, it is equivalent to hitting the Earth in an instant, but this is obviously not true.
But the speed at which it passes is that even if Mars were that fast, it could circle Mars in just 40 days.
The asteroid 1989JA can only reach such a speed when it is close to the Sun, and therefore only when it passes by the Earth 100,000 miles away.
Normally, when an asteroid approaches the Earth, the asteroid's speed is very slow, not even exceeding the Earth's rotation speed.
Therefore, the sentence we mentioned above is false.
When an asteroid is close to Earth, the asteroid's speed will be very slow, not even exceeding the Earth's rotation speed.
Hitting the Earth at such a speed, the asteroid will most likely be burned by the friction of the atmosphere rather than hitting the Earth's surface.
When an asteroid is close to the Sun, its speed can reach 76,000 kilometers per hour, but when it passes by the Earth, it is about the same speed as the Earth, so the speed of reaching the Earth becomes 0.
Of course, this is not true.
When the asteroid and the Earth are relatively stationary, its speed is 76,000 kilometers per hour, and due to its inertia, it takes a long time to reach zero.
In this process, the speed of the asteroid decreases, but not to zero, but whether the asteroid will hit the Earth or not is not insignificant.
Although an asteroid can only reach 76,000 km/h when it is close to the Sun, it will move away from the Sun at such a speed that it is like a marksman walking the world on an iron gun.
The asteroid, like the Earth, is a member of the solar system, so it also rotates around the Sun, but in the process of rotation, there is no friction between it and the Earth, so it is always moving away from the Sun at a speed of 76,000 kilometers per hour.
epilogue
Therefore, when it passes by the Earth, as long as its speed is not 76,000 kilometers per hour compared to the Earth, then it will not hit the Earth.
However, after the asteroid passes, it will be affected by the gravitational pull of the earth, and its orbit will be shifted to a certain extent, although the possibility of orbit change is very small, but it is not zero, which means that it will pose a threat to the orbit of the earth.
It is necessary to strengthen the observation of such an asteroid, and only when we have the true orbital information of it can we effectively resist it.
The technology that can be used to fight asteroids still has a lot to be desired, but in the next 33 years, there may be a big breakthrough, and at that time, there will be no need to worry about this asteroid threatening the earth.