I make a popular science video and all the emperors learn from it!

[Popular science continues.] 】

[Fantasy is always very beautiful, but it is difficult for the space elevator to be realized. 】

[First of all, where to find a 100,000-kilometer-long, light enough and strong enough elevator cable?]

[There is no such cable.] 】

[So far, we know that carbon nanotubes are the strongest material that humans can make, with only a quarter of the density and 100 times the tensile strength of steel, which seems to be the ideal material for making space cables.] 】

[Assuming that the diameter of each carbon nanotube cable is 5 cm, its maximum tensile strength is about 200 GPa, that is, it can withstand about 200,000 Newtons of tensile force per square millimeter.] 】

[Then this cable can withstand up to 40,000 tons of tension without breaking!]

What is the weight of a 50,000 km long (100,000 halves) and 5 cm diameter carbon nanocable?]

[The density of carbon nanotubes is 2.1 grams per cubic centimeter.] 】

[The cable of the space elevator should be of uniform thickness, and the 50,000-kilometer-long carbon nano cable will have its own mass of 206,000 tons, which is more than 5 times the tensile strength of the cable itself!]

[To put it simply, even the strongest carbon nanocables can easily be pulled off in the middle of the space elevator.] 】

[And that's not counting the strong pull exerted on the top counterweight of the ladder.] 】

[Of course, thickening the rope can increase the pulling force. 】

[But the thicker the rope, the greater its mass, and the cable will never be able to bear its own weight.] 】

[So until new and stronger materials come out, space elevators can only be fantasy.] 】

[Even if there is a cable with sufficient strength, how to send it to the sky is a new problem. 】

[The second problem is that the cable cannot be installed.] 】

[The ultra-high voltage cables laid now are usually pulled by drones or helicopters to pull a thin pilot cable, and the heavy cables are pulled across the wide river by pulling the steel wire with nylon wire and strengthening one by one. 】

[However, the cross-river cable is laid horizontally and only a few kilometers at most, while the cable of the space elevator is tens of thousands of kilometers straight up and down without interruption in the middle. 】

[The most powerful rocket of mankind can only send more than 100 tons of payload to low earth orbit, and no rocket can drag hundreds of thousands of tons of cables to geosynchronous orbit at one time. 】

[Not to mention, let it reach an altitude of 100,000 kilometers.] 】

[The third problem is: the life of the space elevator is worrying]

[Even if you build a space elevator with a lot of hard work and a huge amount of money, you can't enjoy it once and for all.] 】

[The space elevator will face a full range of threats from low altitude to high altitude:]

[Rain, wind, sand, and salt spray will erode the cable; atmospheric flow will exert a lateral pull force on the cable, making it bend and tremble; the high-speed up and down movement of the elevator car will cause rapid wear and tear on the surface of the cable; all spacecraft operating in medium and low orbits, as long as their orbits cross the earth's equator, theoretically may collide with the cables of the space elevator at high speed;

Millions of space junk is uncontrollable and unavoidable, carbon nano cables have good tensile strength, but in terms of shear resistance, they are slag, and they will break when they hit, and a large amount of atomic oxygen is distributed in low earth orbit, which can quickly oxidize the carbon on the surface of the cable and take it away, so we need to do enough anti-corrosion work on the surface of the cable. 】

[Affected by the gravitational pull of the sun and the moon, it is difficult for the space elevator to operate stably, and the tidal gravity will pull the space station, the counterweight, and the cable itself, causing it to stretch and sway, which will also shorten the life of the cable. 】

[Once the cable breaks, the result will be catastrophic.] 】

[After losing the restraint of the cable, the counterweight will fly away from the earth at high speed in the tangential direction;]

[At the same time, the Ark space station, located at 36,000 kilometers, will fall to Earth under the tension of the cables below, causing a serious disaster.] 】

【......】

[Building a space elevator, this is really the more you try, the more difficult it becomes. 】

[If this is so difficult, why do scientists still cling to this almost impossible idea?]

[The biggest motivation is to reduce the cost of going to space. 】

[At present, in the launch of international commercial satellites, the transportation cost per kilogram of load is 2000~20,000 US dollars. 】

[Ordinary people who want to travel to space need at least $100,000. 】

[If the space elevator can be built successfully, regardless of the initial construction cost, according to the estimation of the Neon Guoda Forest Group Construction Company, the transportation cost per kilogram of load is about 200 US dollars - that is, it only costs about 70,000 soft girl coins to travel to space. 】

[After the space elevator is built, it will not only make space sightseeing accessible.] 】

[It can also transport materials on earth and space at a low cost.] 】

[This may become the most touching turning point in the history of human space exploration.] 】

[Look up at the sky and imagine.] In our lifetime, we may see a grand ladder that pierces through the clouds and across the heavens and the earth!]

【......】

"It turns out that it was so difficult to build a space elevator!"

"I can't stand it, I'm getting sand in my eyes, this is the spirit of Yugong moving mountains!"

"There should be such momentum, in order to go further, descendants have conquered the land, conquered the sea, conquered the sky, and now space is missing. "

“......"

After reading this popular science, an inexplicable power surged in the hearts of the ancients.

This is the spirit of Chinese people who do not admit defeat and are not afraid of difficulties!

Only foreigners will seek God's mercy when they encounter twists and turns, and the Chinese people have never relied only on themselves and their clansmen!

Han dynasty.

Liu Che's chest is full of pride!

He couldn't agree more with the light curtain.

No matter how difficult it is to build a space elevator, so what?

Human beings have gone all the way from primitive society to experience fewer difficulties?

I don't overcome them all one by one!

When he first succeeded to the throne, it was difficult to hold power within the imperial court, and he was often obstructed by the emperor's grandmother, and even the danger of being deposed at any time.

There are Huns on the frontier, constantly invading.

But he didn't make it through.

not only completely grasped the imperial power, but also beat the grassland people to the ground. (If you read a violent novel, go to Feilu Novel Network!)

Ming dynasty.

Zhu Di was full of emotion.

"The descendants are very much in line with my intentions. "

"It's just... Why is there no Chinese people involved in the space elevator?"

"Do you see that this is not feasible?"

Hearing the emperor's muttering, Yao Guangxiao beside him stroked his beard and laughed.

"Haha, Your Majesty, you can look away from this, and future generations may be quietly developing it. "

"It's a secret. "

"Before something is done, it's not appropriate to publicize it with great fanfare. "

Well?

Zhu Di reacted when he heard this.

That's right.

Just rebelled against him in the first place... No, it's the same as Fengtianjing.

Things are not ready to leak the news. []

Zhu Di laughed with satisfaction, "Okay, that's right, I'm looking forward to what kind of expression foreigners will have when they see Huaxia quietly developing a space elevator." "。