It's true
When I saw this picture, to be honest, I almost thought that the time of waking up was fast forward to 100 years, the era of science fiction has arrived, is it impossible to hide the things of 99 years in the end? According to media reports, from October 23 to 27, the first National Planetary Defense Conference was held in Guilin, Guangxi. You heard that right, it's the Planetary Defense Conference!
The style is as rough as the opening scene of the movie "Star Wars"
What's wrong? Are aliens invading again? What about my fusion engine? What about my anti-gravity vehicle? What about my Italian ion cannon? I believe that many people's first reaction is like this, but in fact, this is a serious scientific conference, the purpose of which is to promote the cross-integration of China's near-Earth small object monitoring, early warning, defense field, which is what earthlings have been doing silently for decades.
Humans have been quietly doing planetary defense work for decades
In the short period of more than 100 years of modern industrial history, we have been threatened by small near-Earth objects, such as the Tunguska explosion on June 30, 1908, and the fall of celestial bodies in Chelyabinsk Oblast, Russia, on February 5, 2013. At 04:38:24 a.m. on March 23, 2020, a near-Earth asteroid numbered 2020 FL2 flew over the Earth at a distance of about 144,000 kilometers, almost wiping the hairs on the tip of our noses, almost allowing humans to start a defense plan to avoid being attacked by dinosaurs, but fortunately the asteroid did not crash into the earth in the end.
The 2020 FL2 asteroid that flies by the sweat on the tip of Earth's nose
For asteroid defense, the prerequisite is to find and track, detect it, thanks to the unremitting deep space exploration of human beings for decades, the United States, Russia, and China currently have corresponding deep space exploration networks, which can timely warn of approaching small objects. Although Japan successfully "landed" on the asteroid and sampled back, it relied on the deep space exploration and communication network of the United States, so it still could not.
Imaginary map of the Japanese Hayabusa-2 landing Ryugu asteroid
Realistic touch moments
After detecting, tracking, and calculating the asteroid's orbit, the next step is defense. At present, the most reliable means of asteroid defense is hard destruction, that is, the use of nuclear weapons, blowing it up or blowing it off orbit, from the special report to be made at the National Planetary Defense Conference, it is known that the "Research on Implosion Ultra-high-speed Launch Technology above 10km/s and Its Application exploration in planetary defense" and "Discussion on the Mechanism of Action and Effect Evaluation of Nuclear Explosion Defense Asteroids" are all discussed.
Are you guys really here?
But the main killing mechanism of nuclear weapons is the shock wave, which needs to have a transmission medium to play a role, such as air and water, and space is a vacuum environment, if it only explodes on the surface of the asteroid, the power of the nuclear weapon will be greatly reduced, not enough to change its orbit, or blow it up, you need to send people to drill holes in the asteroid like the science fiction movie "The End of the World", and bury the nuclear bomb deep. However, with the current space technology of mankind, it is possible to gently "touch" an asteroid like Japan, and it is not yet possible to send people to land.
The most direct way is to launch a nuclear bomb and blow it up
In a vacuum, the power of nuclear weapons is greatly reduced
Not only that, but even if a nuclear bomb explodes inside an asteroid, in exchange for more small objects and debris with unpredictable orbits, it may be self-defeating, and some can still penetrate the atmosphere, posing a huge danger. Therefore, the safest way is to use solar sails, lasers and electric thrusts to keep it away from the earth, which is what current human technology can do.
Drag the asteroid away with a solar sail
A simpler approach is to spray paint on one side of the asteroid to change the efficiency of its absorption of sunlight and heat, thereby changing its orbit. These ideas are all very beautiful, but the only problem is that the output energy is very small, and it takes a long time and process to act, so it is necessary to find the small objects that are most likely to pose a threat as early as possible, and then launch the spacecraft several years in advance, fly hundreds of millions of kilometers to approach and land on the target, leaving enough margins.
Many asteroids are actually colorful in their own right
Of course, near-Earth asteroids are a threat, but also an opportunity and resource, and if one day, our technology develops to the point where we can capture asteroids, rather than the destruction and deviation of Jian'an, then the planetary defense conference will become a planetary mining conference.
If humans are strong enough, it will not be a disaster, but a mine