"Using this, it is possible to build an elevator at the equator at a height higher than that of a synchronous orbit, where the two forces balance,"
Hearing Li Ze continue to explain, Fangran saw him raise his hand to draw, and a slender rectangle extending beyond the outer circle was extended from the inner circle, and the point where it intersected with the outer circle was marked as r0.
Subtle reminiscences of being at once physically dominated.
"In this part below the synchronous orbit, the radius becomes smaller, and the gravitational force formula GMm/r2 means that the gravitational force is relatively large, while for the part beyond the synchronous orbit, the centrifugal force formula mω2r means that the centrifugal force is relatively large,"
No, wait, I always feel that two very familiar formulas have appeared...
Watching Li Ze mark the slender rectangles on both sides of the outer circle in red and blue, indicating that they are 'pulled' in two completely opposite directions by gravitational force and centrifugal force respectively,
Fangran, who was sweating a little, saw his last opening when he looked at him:
"Then as long as the two parts are equally stressed, the space elevator can stand in space without support."
After hearing this, Fangran felt suddenly enlightened and shocked.
"The concept of a space elevator has actually been proposed a long time ago, and the technical principles have been relatively complete."
Lize put away the projector, and the warm light of the bonfire resumed on the narrow mountaintop, while Kerim looked at Fangran and added with a smile:
"It was more than a hundred years ago that Tsiolkovsky proposed this idea. Today's jet rockets and staged rockets are all ideas he proposed back then."
More than a hundred years ago!
For the era before this time, he had a deeper feeling than the two of them. Fangran couldn't believe that when he was driving the carriage through the wheat field,
Someone has already proposed a space elevator, which even today makes him feel incredible.
"Then such a good thing, why not build it?"
Thinking about the series of advantages and meanings the two of them just said, it seems quite feasible to understand the principle, Fangran asked strangely,
Knowing that he would definitely ask such a question, Kerim and Lize looked at each other, as if they were discussing who would explain.
"Because of the tensile strength of the material."
In the end, Kerim answered aloud. He recalled the relevant details he knew as much as possible, and explained softly and helplessly:
"At the same time that the gravitational force and the centrifugal force are balanced, a very huge tensile force will be generated. To meet the requirements of the space elevator, I remember that the specific tensile force per unit area needs to be greater than the material density times... "
"Okay, let's just give an example."
I always feel that he is recalling a number that he does not understand the origin of when he said it. In the middle of the night, he faces four people who are more knowledgeable than himself.
Fangran spoke directly and silently without any fluctuation.
"Haha, if you use the density of steel as an example, it would take about 4 million times the atmospheric pressure, that is, a steel cable as thick as a thumb to lift 4,000 tons of weight,"
"But the actual steel cable can only do one-thousandth of the level, and its density is too much."
Hearing what Fangran said, Kerim couldn't help laughing and gave an example directly.
"In other words, it is also stuck on the material..."
For such an answer, thinking of the problems he faced not long ago, Fang Ran had no choice but to develop some new materials.
"It's not completely stuck on the material. In fact, a material that can satisfy the space elevator has been discovered now,"
Already discovered new material
Surprised that he didn't get stuck on the material, Fangran looked at Kerim unexpectedly, and saw him smile and say a name.
"Carbon nanotubes, the material has excellent tensile strength, and its density is only one-sixth of that of steel. It can already be produced with the current technology in reality."
"No, wait a minute, since you've discovered the material and you've never heard of it, you're going to say that this material is either ridiculously expensive or laborious to make..."
I was not too happy too early, I was keenly aware of the strange place, and dug out relevant memories from the remaining high school knowledge,
Fangran looked suspiciously at Kerim and asked silently:
"I remember that the synchronous orbit seems to be more than 36,000 kilometers, plus the above section, how many carbon nanotubes can be produced?"
"Half a meter."
Fangran: "..."
Hey, good guy, it's still about meters...
He was speechless, staring at Kerim unable to speak,
half will,
Only then did Fangran burst out laughing. He covered his stomach and looked up at the Milky Way above his head. For some reason, he couldn't help laughing and complained:
"Banmi... Poof, my god, half a meter is too much, hahahaha!!"
"I remember this was made by a laboratory in your Huaxia."
Seeing him like this, Kerim couldn't help but smile, and Rize also smiled slightly.
"At least in terms of tons, it still gives me some hope."
I don't know why I'm smiling so happily, Fangran wiped the corner of his eyes and looked at Lize and Kerim, it turns out that this is what they both said to be "more realistic",
Half a meter is more than 36,000 kilometers, the difference is not even a star.
But thinking about the light-speed engine that has no theory about deep space navigation, the half-meter that has been completed is indeed more realistic.
Thinking that even the first step into the universe, space exploration at a distance close to the earth, is still half a meter to tens of thousands of kilometers away,
At this moment, looking up at the Milky Way,
Only then did Fangran truly understand the distance to the starry sky above his head,
Even the solar system cannot travel, how far is it from the Milky Way with hundreds of billions of stars, the Local Group of galaxies to which it belongs, and even the upper Virgo and Laniakea superclusters... .
But remembering that more than a hundred years ago, when there were no rockets, someone had already proposed the idea of a space elevator,
And suddenly feel that this distance does not seem to be eternal and unreachable.
"Speaking of which, in reality, the length of half a meter can be made. If it is replaced by the technological level of the night battle, can a space elevator be made!?"
As if he suddenly thought of something beyond reality, Fangran asked with bright eyes when he mentioned this.
"It's not that simple. It's true that night battles have a higher level of technology than the reality, but most of the fragmentation is biased towards weapons and mechanical development, and there may not be related technologies,"
As an elite technologist, Li Ze shook his head and said the most important reason while looking at the Milky Way starry sky above his head.
"And no one knows whether the night battle technology will flow into reality, and whether it will be a space elevator."
"That's it, eh! By the way, is there anything similar to a space elevator... ."
Following the sudden voice of the young man who seemed to understand, he asked curiously again,
In the midnight full of fantasy, discussing the topics of technology and starry sky,
On the narrow mountain top like an isolated island in the sky, three young people sat on the tree stump around the bonfire, with the magnificent Milky Way and the distant starry sky above their heads. Their enthusiastic words lasted for a long time at night,
The figure was jumped to the camera by the two birds, lightly pecking the shutter to record... .