Is 2035 the end of the earth?

The news that the asteroid numbered "2003QQ47" may hit the earth in 20 14 was forwarded by CNN. Although this possibility was completely ruled out later, according to the Youth Times, astronomical scientists said that an asteroid would eventually hit the earth. According to historical experience and scientific prediction, this problem is only a matter of time.

Astronomers in China told reporters that there are about 1400 near-earth asteroids, of which nearly 600 threaten the earth. Jupiter's gravity is the main cause of near-earth asteroids.

Li Jing, a researcher at the National Astronomical Observatory, told the reporter: "If the diameter of the asteroid that hit the earth is more than one kilometer, then the disaster is global, and no place can avoid being killed, while the smaller one will not have such a big impact, but will only have a disastrous impact on the local area that hit."

If the asteroid is really going to hit the earth, can human beings brilliantly direct a blockbuster "Man can conquer nature"?

Option one: blow up an asteroid with a nuclear bomb

According to Li Jing, a researcher at the National Astronomical Observatory of China, there are two ideas in the scientific community to "intercept" asteroids. One is to blow them up and destroy them; The other is to change its orbit.

For the first solution, some scientists have put forward a bold idea: using nuclear missiles to attack objects flying towards the earth-just like the method used by Hollywood movie star Bruce Willis in the movie Hami Keaton, such as launching a rocket and a missile, and then blowing it up.

The method of "blowing up" is feasible in theory, but researcher Li Jing said that before blowing up, we should first study the origin of the small celestial body that is going to crash into the earth to see whether it is composed of iron or silicon. If it is silicon, it can be blown up by missiles or other nuclear devices because of its loose texture, but if it is iron and it is a hard "iron knot", it is necessary to change its orbit.

Weaknesses and doubts: Because the consequences of nuclear explosion are unpredictable, the method of "blowing up" has obvious shortcomings. Researcher Li Jing said, "If we don't do it well, the blown debris will be scattered on the earth, and people will lose control of them, which will cause more suffering to mankind."

There are still some problems in the use of nuclear weapons. Because all the accumulated nuclear weapons on the earth are only enough to blow up an asteroid with a diameter of 9 kilometers, and they must hit the center of the asteroid accurately.

Zhu Jin, a researcher at the Beijing Observatory of the Chinese Academy of Sciences, also believes that this method may not be effective, because humans have not yet mastered the ability to launch weapons directly into outer space. When the asteroid is far away, people can't observe its material properties; For some stars with loose structures, the effect of explosion is very limited.

Option 2: Change the track with mechanical force.

More scientists are considering ways to change the orbit of asteroids. Researcher Li Jing said that the first way to change the orbit of an asteroid is to launch an artificial celestial body, and then adjust it to be parallel to the asteroid (or asteroid) after it is launched into space, and make the relative speed between them zero, that is, the running speed of the artificial asteroid is equal to that of the asteroid, and then it will change the orbit by mechanical propulsion.

Weaknesses and Doubts: Researcher Li Jing believes that this method is relatively safe, but it is difficult to go through continuous and sufficient experiments without any mistakes. If the first push is unsuccessful, you have to launch an aircraft to track it, and then push it at the right time to change the orbit.

Option 3: Change the color and change the track.

The second way to change the orbit is to change the surface color of the asteroid. Researcher Li Jing said that if the original asteroid is gray, it can turn into pure black, and the color of the object can determine how much heat it absorbs. "This can change its albedo, and its heat absorption will also change after the color changes. Black can reduce albedo and increase heat absorption rate, thus increasing the temperature of the whole planet itself and affecting its orbit; You can also turn it white and cold, and the effect is the same.

Weaknesses and doubts: Changing the color of an asteroid can change its orbit. But the premise is that it takes a lot of time to accumulate thrust, and it is necessary to study and monitor the actual impact on asteroid orbit at any time. Otherwise, the method of resisting asteroid impact may also cause it to hit the earth more directly.

In addition, because all the planets that can pose a threat to the earth are more than one kilometer in diameter, the whole project will be extremely huge. From the author's dull eyes, it is obvious that humans don't have time to extract enough pigments from asteroids to change their colors. How can so much paint be transported to the asteroid and how many people will be sent to complete such a great painting task? It is reported that the cost of the US space shuttle per kilogram of payload is about $65,438+0,000. An asteroid with a diameter of one kilometer needs about 523 tons of paint. Even if the cost of buying paint is not included, the freight required to transport these paints into space is about $5.24 billion.

Option 4: Change the orbit by explosion.

The orbit of an asteroid can also be changed by explosion. For planets with iron and solid structures, researcher Li Jing thinks that missiles or nuclear devices can be used to attack them. The ideal state is to blow it into two parts, so that the quality changes. "It is not the original quality, and the track has changed."

Weaknesses and doubts: At present, these theoretical discussions can only be carried out in an ideal state, and there can be no errors in practice, so the difficulty can be imagined.

Option 5: Install a "solar sail" for the asteroid.

This scheme is to install a large rocket engine or "solar sail" on the surface of an asteroid to push the planet out of Earth orbit. The engine will be sent to an asteroid by a conventional rocket; Then, the engine itself is fixed on the asteroid, and the engine is started to push the asteroid out of its original orbit, so that it misses the chance of colliding with the earth.

Another option is to install a "solar sail" on the asteroid instead of an engine. Sails are sent to asteroids by conventional rockets and take root on the surface of asteroids. Once the sail is attached to the surface of the asteroid, it can absorb the photons emitted by the sun, thus pushing the asteroid out of its original orbit like the wind blowing the sail on a ship.

Microsatellites can also be used to land near-earth objects heading for the earth, and to see the substance, shape, size and composition of near-earth objects. The researchers said that this information is crucial to push any near-earth object that rushes to the earth out of orbit.

Weaknesses and doubts: Generally speaking, although these technologies are all established in theory, the practical feasibility of this technology needs further experimental research.

All plans are just ideas.

Researcher Li Jing believes that it will take another 50 years to prevent asteroids from hitting the earth with the existing technology and means of mankind. In this long enough time, people should continue to study and experiment, and gradually improve and mature the technology. "In theory, humans have a way to prevent asteroids from hitting the earth, but they have not done experiments in this area. Although the United States and Russia have mastered this technology and these technologies are feasible, they have not been tested or really implemented. It's easy to say, and there may be problems in practical application, so it will take some time for the technology to mature gradually. "

Scientists believe that the flight speed of asteroids may exceed the speed of existing human aircraft. When it doesn't hit head-on but approaches in the same direction, the aircraft launched by human beings can't catch up with it in a short time. Therefore, humans can only find them early and launch the aircraft into outer space to "wait" and then try to push it out of orbit. The farther this "battlefield" is from the earth, the safer mankind will be. Therefore, monitoring is the first priority, and the longer the warning time, the better.

Regarding China's monitoring of asteroids, researcher Li Jing told reporters that China's astronomical monitoring station in Xinglong County, Hebei Province used to be very influential internationally, but in recent years, countries have generally strengthened research in this field, and we have fallen behind.