Earth Era

The definition of conventional propulsion method is actually very simple, that is, a propulsion method that can be widely used on a large scale. Just like the propulsion method used by the Xinghai spacecraft at the moment, which uses a fusion engine to heat the working fluid and then eject it.

Corresponding to the conventional propulsion method is the unconventional propulsion method. Most of these methods of advancement are still in the conceptual stage, and there are many whimsical methods. For example, a nuclear bomb is thrown every second and explodes behind the spacecraft, and the radiation pressure of the nuclear bomb is used to propel the spacecraft forward. This kind of propulsion method has one thing in common, that is, they are only needed under very special circumstances, and they are not qualified for large-scale interstellar transportation needs.

For long-distance interstellar navigation, the only option is conventional propulsion. The reason is simple, because in the future, a large spacecraft that may carry hundreds of thousands or even millions of people will need to continuously drop nuclear bombs to propel itself. This kind of thing is unimaginable to anyone.

In the field of interstellar navigation, it will not work to take the wrong approach. The only feasible way is to develop basic technology honestly and develop conventional propulsion methods.

But... Chu Hai now told Wei Feng that some scientists have theoretically proven that the upper speed limit of conventional propulsion is 4,500 kilometers per second. Although this theory has not yet gained universal acceptance, it has some supporters.

This caused Wei Feng's heart to ripple once again.

"The scientist demonstrated this issue from the aspects of material technology, specific impulse, the ratio between the mass of fuel and working fluid and the total mass of the spacecraft, navigation distance, basic theory, etc. His conclusion is that to carry out long-distance interstellar voyages, If our basic theory cannot achieve a breakthrough, the upper limit of the speed we can achieve through conventional means is 4,500 kilometers per second. If the speed of a spacecraft exceeds this upper limit, then it will slow down because there is not enough fuel. , thus becoming a cosmic island drifting in the universe that can never stop, and all people living on this island will be trapped and die here due to exhaustion of fuel." Chu Hai wrote in the letter.

"Some scientists pointed out that there is a loophole in this theory. The scientist retorted that if the speed of a spacecraft depends only on these factors, then people can build a very large spacecraft. For example, the length can reach ten Kilometers, a giant spacecraft with a width and height of one kilometer. Then only 10% of the space in this giant spacecraft is piled with fuel, and only 10% of the space is used as a living area. Even so, the spaceship It can still sustain at least 10,000 people for thousands of years, and the fuel is enough to accelerate the spacecraft to 40% of the speed of light, which is a speed of 120,000 kilometers per second. In terms of the fuel consumption of the giant spacecraft After that, we don't have to slow down the entire spacecraft. We just need to separate the manned area from the spacecraft, and then only slow down the manned area, because the manned area only has a very small mass compared to the entire spacecraft. Slowing down the manned area also requires only a limited amount of fuel consumption, which can break the "conventional propulsion speed limit"."

"In this way, we will be able to send 10,000 people from the solar system to the South Gate II system in only eleven years."

Seeing this, Wei Feng frowned slightly. Wei Feng didn't know whether the conclusion that "the upper limit of conventional propulsion speed is 4,500 kilometers per second" was correct or wrong, but Wei Feng knew that the method used to refute the above conclusion must be wrong. It also has huge holes.

First of all, ignore the high level of materials and structural technology required to build such a giant spacecraft. Just assume that people can build such a huge spaceship, but even so, can this method be commonly and widely used? No. It still doesn't work, because this method is still an "unconventional propulsion method." Abandoning such a huge spacecraft for every interstellar voyage is obviously unacceptable in terms of cost. In other words, there is no essential difference between this navigation method and the navigation method of dropping nuclear bombs. Neither of them is capable of meeting the needs of large-scale interstellar navigation.

Sure enough, just as Wei Feng thought, Chu Hai then wrote down the rebuttal words of the scientist who proposed the theory. Those words were basically the same as Wei Feng's thoughts.

In this letter, Chu Hai went on to describe other scientists' refutations of this conclusion, without exception. None of these objections can be applied to large-scale interstellar voyages. According to Chu Hai, although the "upper limit" theory has not yet been recognized by most people. But at least until now, no one has been able to refute it effectively.

Wei Feng felt a little melancholy in his heart. If the "ceiling" theory turns out to be true, it promises a dire scenario. In the future it predicts, human civilization will forever be trapped in a small solar system, unable to take steps toward interstellar navigation until its demise. At the same time, it also indicates that the interstellar voyage that I am undertaking at this moment is of little significance. After all, interstellar navigation through long-term hibernation is also an "unconventional navigation" method in the strict sense, and it is also impossible. Competent for large-scale interstellar navigation needs.

This is different from the moon landing missions of human civilization hundreds of years ago. That kind of lunar landing method can send one person to the moon. With the development of science and technology, it will inevitably be able to send 10,000 or 100,000 people to the moon. In other words, this method has large-scale applications. development potential. Now, the hibernation method can send Wei Feng to another star system alone, but if the sailing speed cannot be increased, even in another ten thousand years, this method can still only send a few people to other star systems. In other words, this mode of navigation has no development potential.

What human civilization needs is a safe, reliable and fast interstellar navigation method that can be used on a large scale within a life cycle. Even if this method cannot be applied on a large scale at this stage, at least it must show the potential for large-scale application. For example, if there is a spacecraft at this moment, and its sailing speed can reach 50% of the speed of light, which is 150,000 kilometers per second, then it will only take more than eight years to go back and forth to the Nanmen II system, even if it only takes Able to carry one person, this method also has potential, because it indicates the feasibility of large-scale interstellar navigation in the future. Whether it is nuclear bomb-throwing navigation, super giant spaceships, or the hibernation navigation currently used by Wei Feng, these three methods have no potential for large-scale application.

But now, the upper limit theory proposed by the scientist has locked the speed of conventional propulsion at 4,500 kilometers per second. He declared that unless one could increase this speed tenfold, or increase the average human lifespan tenfold, any remaining attempts would be doomed to fail in large-scale application.

"Whether it increases the speed by ten times or increases the average human life span by ten times, it is impossible for us to achieve it at present." Chu Hai wrote, "The development of science and technology requires the support of basic theories. If our Without a breakthrough in basic theory, these two requirements are extravagant for us."

"Science is a weapon for us to understand the nature of the universe. It follows a process of discovery, hypothesis, and demonstration. We must first discover the places in the universe that are different from our theories, and then put forward hypotheses about this, supplemented by more Observe and think, and finally come up with a new theory, and then continue to repeat this process, our scientific and technological level will be improved. But my friend, you know, some scientists have now put forward a new statement, which says Our field of vision is limited within the solar system, that is, if we cannot go out of the solar system, we will not be able to discover more unique features of the universe, we will not be able to better understand the universe, and our science and technology will naturally not be able to develop. .”

"And if the "upper limit" theory is true, it means that with our current technology, we cannot leave the solar system on a large scale. But we cannot leave the solar system. According to the above theory, our technology cannot develop."

"Wei Feng, do you understand? This is a knot that cannot be opened."

Wei Feng temporarily looked away from the display screen and fell into deep thought.

To simplify this knot even further, it means that if you want to achieve higher navigation speeds, people must go out of the solar system and acquire more knowledge. Without more knowledge, we cannot obtain higher speeds and cannot get out of the solar system. If you want to get a higher speed to get out of the solar system, the prerequisite is indeed more knowledge and higher technology.

"Going out of the solar system" and "acquiring more knowledge" are a pair of mutually prerequisite events. This situation is like a key being placed in a lock. To open the lock you must first remove the key, and to remove the key you must first open the lock.

It is this paradox that tightly limits the pace of human civilization to the solar system.

"Then... through hibernation voyages, super giant spaceships and other unconventional methods, first let a small number of people go out of the solar system to acquire knowledge, and then use this knowledge to feed back the people trapped in the solar system, and ultimately improve the level of knowledge of human civilization. Raising it to the point where interstellar navigation can be carried out on a large scale, this may be a way to open the dead knot." Wei Feng thought, "Maybe the isolated island plan is an attempt by human civilization to open the dead knot." (To be continued.) ~^~)