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Space Elevator

neal.fun

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Re: Space Elevator

#171

Post by hnuser123456 »

hwillis wrote: post #126
dpq wrote: post #61

Amazing work! One minor correction: > As particles from the sun hit the atmosphere, they excite the atoms in the air. These excited atoms start to glow, creating brilliant displays of light called auroras. The process is a bit more nuanced than that. The modern mainstream understanding is that the growing pressure of the solar wind makes the tail of the magnetosphere "contract" (sort of pushing it inwards from the si…

Any discussion of aurora which do not mention space tornados: https://en.wikipedia.org/wiki/Space_tornado Is inherently incomplete. Not necessarily because they're needed to explain it, but they do need to be brought up at any time possible because they're cool.

I feel that way about galactic center filaments. They just scream "this region of space is not safe" in the most awe-inspiring way to me. 150-lightyear-long, magnetically powered, speed-of-light tornados. And there's hundreds of them.

https://en.wikipedia.org/wiki/Galactic_Center_filament

https://science.nasa.gov/asset/webb/milky-way-center-meerkat...

Re: Space Elevator

#172

Post by bentt »

Seems like even before we do an elevator, we should get _something_ tethered to the ground to be in space. Like... anything! That'd be a huge accomplishment.

Re: Space Elevator

#173

Post by joenot443 »

enraged_camel wrote: post #162
seanc wrote: post #150

Earlier quoted context omitted.

Kim Stanley Robinson's description of a Martian space elevator falling and wrapping twice around the entire planet convinced me that they aren't a good idea. https://www.kimstanleyrobinson.info/content/clarke

A version of this also happens in the first season of Foundation, the Apple TV series based on Asimov's novels.

Would you recommend that show to the HN crowd? The books are super well liked around here, for good reason.

Apple's put out a staggering amount of content the last few years, I wasn't even aware this one debuted!

Re: Space Elevator

#175

Post by cmpb »

michaelbuckbee wrote: post #160
isgb wrote: post #133

> Space elevators are actually a possible idea being considered by scientists. > The hard part is making a strong enough cable. And finding enough elevator music... Most engineers would bring up a lot more issues than just finding a strong cable. Also, most attempts with e.g. carbon nanotubes have been abandoned ages ago https://www.newscientist.com/article/2093356-carbon-nanotube... . - We don't have a good ascent m…

In John Scalzi's Old Man's War, there is a discussion of how the more advanced society that they're interacting with deliberately put a space elevator on Earth, not because it was the easiest or cheapest solution, but as a sort of constant reminder of just how much more technologically sophisticated they were.

Really great book (and series). Though it's not "hard sci-fi" by any means, the technology feels real enough to keep my brain from focusing on the holes and enjoy the fun philosophical and ethical problems that Scalzi comes up with

Re: Space Elevator

#176

Post by Pxtl »

messe wrote: post #158
jvanderbot wrote: post #143

Very cool. One thing I wish was better shown: space is close, it's just hard to go up. Our liveable breathable atmosphere is razor thin compared to the size of earth. In most cases, 100km is less than the distance between sizeable metropolitan areas. It's a day long bike ride. Air runs out less than a bus ride across town. A 15k jog/hike would put you in the stratosphere. Those jet aircraft that seem so high are clos…

> it's just hard to go up Going up is the comparatively easy part, it's not exactly rocket science. Going fast enough sideways so you stay up there is the tricky bit.

Which is another part of why a space elevator is nifty - by definition it extends out to a distance where you are going fast-enough-sideways.

Now, I have no idea how practical it is to build one (Angela Collier has a video saying it's kinda ridiculous), but it's a cool idea.

https://www.youtube.com/watch?v=Z5aHMB4Tje4

Also since rockets have moved away from hydrolox, it would be nice to have a greener launching system.

Re: Space Elevator

#177

Post by vdqtp3 »

tsimionescu wrote: post #164
icetank wrote: post #84

Earlier quoted context omitted.

You only need to defend the easy to reach parts. So the base and the cargo pod. To hit the upper parts you need advanced rockets and targeting systems.

Why advanced? It's a stationary target that's 35,000 km long. I don't think it would be that hard to hit. Not to mention, securing the cargo would be an extremely difficult task in itself, especially when one of the main thinga you'd like to raise through the space elevators is rocket fuel.

> stationary target that's 35,000 km long

and what, 12" wide? 24"? that's still very difficult to target

Re: Space Elevator

#178

Post by raducu »

aDyslecticCrow wrote: post #166
messe wrote: post #158

Earlier quoted context omitted.

> it's just hard to go up Going up is the comparatively easy part, it's not exactly rocket science. Going fast enough sideways so you stay up there is the tricky bit.

> Going fast enough sideways so you stay up there is the tricky bit. nah, thats the simple part. getting up there efficiently is the difficulty. once we're up, its just a matter of force over time to create a nice orbit. The faster you go, the more friction you face, and the more heat and vibration your equipment must endure. Going slower reduce friction and stress but use more energy just negating gravity. Slow rock…

> once we're up, its just a matter of force over time to create a nice orbit.

It depends what you mean by "up there". ChatGpt tells me you'd free fall from 1000 km to 100km in about 8 minutes. It also did the math that you'd need 1.65G of sideways thrust to reach orbital speed. That's quite a bit of force for spacecraft sized objects.

If you have an actual space elevator, sure, you can go to close to geosynchronous altitude and by that time you'd have enormous sideways velocity just by being dragged sideways by space elevator and indeed it would be easy to propel yourself to orbit (above a certain altitude my intuition tells me you could let go of the rope and while you'd end up on an eliptise you'd still be in orbit)

Re: Space Elevator

#179

Post by sojournerc »

ddoolin wrote: post #165
daniel_iversen wrote: post #4

This was incredible! Couldn't stop scrolling and reading. For a kid of a certain age and curiosity it'll blow their mind! I'm so grateful the creator made this, shame that his "buy me a coffee" isn't a simple PayPal or Apple Pay but you have to put in credit card or bank details!!

How do you pay with PayPal if not putting in your credit card or bank details? link is a pretty well-known online wallet and much simpler to use than PayPal.

I've never heard of link, so it's the difference between a random website and a well established brand. Not that hard to understand why someone might be hesitant to put in their cc details.

Re: Space Elevator

#180

Post by gizmo686 »

isgb wrote: post #133

> Space elevators are actually a possible idea being considered by scientists. > The hard part is making a strong enough cable. And finding enough elevator music... Most engineers would bring up a lot more issues than just finding a strong cable. Also, most attempts with e.g. carbon nanotubes have been abandoned ages ago https://www.newscientist.com/article/2093356-carbon-nanotube... . - We don't have a good ascent m…

Isn't the entire point of the space elevator to be the ascent/descent mechanism?

Once you have the cable up, you can grab onto it and pull yourself up.

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