When people fly in space for a long time, they will encounter many challenges, so the farthest planet they have ever been to is the moon, the nearest neighbor of the earth. However, no one can take the place of human beings to fly further to the planet, or even to fly outside the solar system.
Voyager 2 embarked on NASA’s unprecedented star trek in 1977. In the solar system, there are four largest planets – Jupiter, Saturn, Uranus and Neptune. After passing through several large planets, Voyager 2’s gravity acceleration enables it to escape the sun’s gravity, thus enabling it to rush out of the solar system with inertia without power.
But when Voyager 2 enters the edge of the solar system, it will encounter a super hot “wall of fire.”. What is the “wall of fire” deep in the solar system? Does this prevent Voyager 2 or future humans from leaving the solar system?
Voyager 2 began to reach the top of the solar wind from an altitude of 18 billion kilometers. Because of the strong electromagnetic wave, the sun will release high-energy particle flow, thus forming the solar wind. This solar wind will continue to spread out until it comes into contact with the medium from the interstellar space, forming a huge solar ring, whose boundary is the so-called solar wind zenith.
For the first time, astronomers have detected the state of plasma deep in the solar system with the plasma analyzer carried by Voyager 2. It is found that the top of the solar wind is not directly connected with the interstellar space, and there is a hot interstellar plasma wall between them.
The temperature of the “fire wall” is estimated to be at least 30000 degrees, with a maximum of 50000 degrees. Its width is 220 million kilometers, 1.5 times the distance from the earth to the sun. So, will the high temperature of “firewall” make Voyager 2 vaporize directly? Can’t man leave the solar system?
Despite the high temperature of tens of thousands of degrees, firewall can’t destroy Voyager 2, because in fact Voyager 2 can receive very little heat. Please note that temperature and heat are two concepts. High temperature does not mean high heat.
Temperature reflects the average kinetic energy of a particle. The more intense its thermal motion is, the greater the average kinetic energy is, the higher the temperature is. But if the particle density is very low, even if the temperature is high, the heat per unit space is very small.
Because the plasma in the firewall is very thin and Voyager 2 can absorb very little heat, it can safely pass through the firewall. In fact, when Voyager 2 was flying there, the average temperature of the whole universe was very low, less than 3 degrees higher than its absolute zero, so it entered the ultra-low temperature state.
Today, Voyager 2 has crossed the “wall of fire” and entered a vast space full of interstellar media. The unpowered Voyager 2 continues to slow down due to the sun’s gravity, and its current speed relative to the sun is 15.3 km / s. However, Voyager 2 is always faster than the escape speed of its solar system, so solar gravity can’t pull it back after all.
At present, traveler 2 has been 18.8 billion kilometers away from the solar system, but it is far away from the solar system. It only contacts with the interstellar medium from the top of the protective solar wind layer. At Voyager 2’s current speed, the radius of the solar system is estimated to be 1 light year, or 9.46 trillion kilometers, 16000 years away from the earth.
Traveler 2 gives us an intuitive sense of the vastness of the universe. Human beings will be trapped in the solar system for a long time. If we can’t build subluminal spaceships in the future, or use wormhole as the basis for space travel, we can’t even rush out of the solar system.