Most of humans and the thousands of living species on the earth live on the surface of the earth. Natural disasters that can threaten humans and other living species on a large scale are asteroid impacts, besides the volcanic eruption of the earth itself. Because the Earth is always traveling through the solar system, small near-Earth celestial bodies are often visited in the orbit. The speed of these small celestial bodies is about the same as that of the Earth, at about 30 kilometers per second. If a small celestial body with a larger mass hits the Earth, a major disaster will occur. The dinosaurs 65 million years ago are said to have been extinct in this way. The Tungus Big Bang more than a hundred years ago is also a "masterpiece" of asteroids. A 2,000 square kilometers of forests near the landing point have been swept away.
At 7:14 Beijing time on September 27, the first planetary defense test of mankind was carried out tens of millions of kilometers away from the earth. A probe from NASA (NASA) hit an asteroid called Dimorphos. This test is part of NASA's "Dual Asteroid Redirection Test (DART)" mission.
There are many observatories on Earth. relies on large astronomical telescopes to conduct real-time observations on this impact event . After the impact occurred, the brightness of the hit asteroid system instantly increased by 10 times, reaching 2.5 visual magnitude . It can be clearly seen that the dust cloud splashed out in an arc shape, and the subsequent effect of the impact is under observation.
The moving white dots in the picture above are very small at first, but then they become brighter, which is what happens when the detector and the small stars collided.
The upper and lower pictures are all scenes at the impact moment, and it is obvious that the light has changed a lot.
The animation above is the state change at the moment of collision.
Dimofus is one of a dual asteroid system with a diameter of about 170 meters and orbiting another asteroid with a diameter of about 780 meters. This dual asteroid system was discovered in 1996. The two were tens of millions of kilometers away when they were closest to the earth, dozens of times the distance between the moon and the earth, and there was no possibility of impacting the earth. Its farthest distance was more than 300 million kilometers.
The purpose of this impact test is two main purposes. One is to detect how much the asteroid orbit changes the kinetic energy impact of the spacecraft is? Can this method be used to change the orbit of the asteroids so as to force the asteroid away from the earth in the future by using kinetic energy impact? Although from theoretical calculations, the impact of asteroids on asteroids can slightly change the orbit and state of the asteroids, most asteroids have relatively loose structures and the matter above is relatively soft. Their own buffering effect may be able to resolve the kinetic energy of the spacecraft, so it needs to be verified by experiments.
Dimoffus asteroid surface condition
Another purpose is to observe the operational changes of another asteroid by slightly changing the operating speed, direction, orbit, etc. of one of the dual asteroid operating systems, and to test the gravitational conditions and interactions between celestial bodies in space. This is also the reason why this experiment was named "Double Asteroid Redirection Test".
This time, NASA chose an asteroid that could not hit the earth at all. Perhaps it was for the sake of safety. In fact, the main purpose of this test is to verify the feasibility of changing the orbit of the asteroid through kinetic energy impact to prevent it from hitting the earth. Therefore, it is also considered to be the first "planetary defense test" implemented by humans. From this perspective, the significance of this test is quite significant, but it is still too early to mature the technology. However, human technology has the ability to intercept near-Earth asteroids. For example, if the probe is changed to a nuclear bomb in this test, the interception capacity will undoubtedly be greatly increased.
Many friends also know that my country also has a "near-Earth Asteroid Defense System" plan, which is also the purpose of defending large-scale near-Earth asteroids into the impact of the earth. At the first National Planetary Defense Conference held in October last year, Wu Yanhua, deputy director of the National Space Administration, said that we will "strive to implement a technology experiment on orbit change to a certain asteroid (orbit change technology) at the end of the 14th Five-Year Plan or 2025 or 2026." We will make our contribution to the future of mankind's real response to the threat of asteroid extraterrestrial bodies to the earth's home.
Reference:
"Jimu News" September 27 "The American spacecraft successfully hits the asteroid NASA official: Opening a new era of mankind"
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