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  • Cethin@lemmy.ziptoRPGMemes @ttrpg.networkAll of 'em defeated with one line
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    10 months ago

    Lol. None of this had to do with Musk. I don’t know why you brought him up. If anything, a space elevator is anti-Musk, as he owns a rocket company, but whatever.

    You can’t just maneuver a space elevator. The entire way it works is it sits at one point. The amount of forces it’d put on the structure to maneuver it is insane, especially if it has to be in time to avoid a hurricane. It has to stay at the equator, so it can only move along that axis, and the speed would need to be insanely fast. Basically, the structure needs to be built to multiple times the minimum required if you’re going to be moving it, without a stable base platform to have oscillation dampeners or whatever on.

    The cable can maneuver to avoid trash and satellites, and satellites can maneuver to avoid the cable. Shielding can be applied to protect it from micrometeoroid impacts.

    Trash can’t be maneuvered. We don’t even know where 100% of it is. You can’t shield the cable. The weight of the cable is the entire issue why we need insane materials to build it. If you add shielding then you’re adding to the weight, and therefor multiplying the size the cable needs to be. A cable made of steel literally needs to be larger than the size of the known universe because you need more weight to support more weight. It compounds. If you add shielding with a different material, you run into the same issue. The cable has to be very light so the compounding size doesn’t grow to impossible levels.

    Space elevators aren’t “pop-sci”. There’s a plenty of real research that says that one is possible…

    … The people who did that research weren’t idiots and did in fact account for everything you brought up rather than just assuming a perfect vacuum and spherical cows.

    I didn’t say they’re idiots. They know what they’re talking about. Most of them are doing physics papers just showing how the calculations work out, not engineering. It isn’t stupid to assume spherical cows if the shape doesn’t matter to you. Physics is not engineering, just math.

    The people who opened companies “doing research” into it have all shut down. Either it was a scam or they realized it isn’t possible. I’m leaning towards scam, because, like you said, I don’t think they’re stupid. They know other people are, and will give them money because it sounds cool and they don’t know any better.

    The people doing materials science adjacent to this are not doing materials science to build a space elevator. They’re just trying to come up with new useful materials. They may write a paper about how it could potentially be used in a space elevator, based purely on the math, because they looking for grant money, recognition, or a media attention for a product for investment purposes or to sell. They aren’t stupid. It’s just useful.

    Space elevator on the moon? Sure. That is somewhat reasonable, though still far out of our grasp. Space elevator on Earth? Not happening. We’ll have fusion reactors and nearly unlimited energy well before we even have the ability to build the mathematically minimum version, without any safety margins or defence for the environment, or systems to deal with vibrations/perturbations.


  • It’s impossible. You didn’t “explain” anything. It’s on the very edge of being physically possible in a perfect vacuum. That’s it. Consider how a hurricane effects a building. The building requires a ton of extra infrastructure/strength to keep it from breaking. Even the most exotic material possible it’s still on the very edge of technically possible, that if you add any extra overhead to protect from the environment it isn’t possible. Then there’s also satellites and space trash which will be hitting the cable. It’s not a thing that can work on Earth.

    then proceeded to spout strange and verifiably false nonsense like this on multiple different points.

    Sure… How do you deal with wind on a space elevator? I’m making strange and varifiably false nonsense? You’re repeating pop-sci stuff as if it’s real, without considering how it’d actually need to be to exist. We can barely build buildings that withstand storms. How is a thin cable going to? Carbon nanotubes are only good for tensile strength (resistance to tension). Shear strength is significantly lower, which is what would be required to withstand forces like weather or impacts. Even assuming it’s possible to make the cable, it wouldn’t work because of this.

    I don’t care how many pop-sci articles or YouTube speculation videos have been made saying it’s totally possible and just around the corner. They ignore the reality and only discuss the absolute minimum vacuum requirements. It makes a much more appealing article/video to say it’s actually possible than to point out that, in reality, it isn’t because there’s a lot of additional things that were ignored.

    This video talks about some of the issues realistically, though it’s mostly focused on math. It mostly is in the position of “if it were possible, why would we even want it” though, not is it actually possible: https://youtube.com/watch?v=Z5aHMB4Tje4&pp=ygUcYXJlIHNwYWNlIGVsZXZhdG9ycyBwb3NzaWJsZQ%3D%3D