As I understand it (see: not at all), if you leave a spaceship with no suit on, you’d get baked like Marie Curie’s ovaries from the radiation. It’s mainly our atmosphere that protects us from most of the nastiest stuff. Would a giant cable reaching from Earth all the way to a platform outside the atmosphere become dangerously-radioactive over time? And if so, would that eventually cause the entire planet to get radioactive over hundreds of years? Kinda like if the hole in the Ozone layer were replaced with a Mario pipe.
And if that is the case, maybe we could forget the elevator aspect of it and just aim for a free eternal source of radioactive energy, like a really shitty Dyson sphere 👀
I’m wondering what would keep the part in the atmosphere from building up a massive electrostatic charge.
Radiation isn’t water and the cable wouldn’t be absorbitant. 🤨
That’s the least of the worries facing the construction of a skyhook. I don’t think Heinlein’s Kenya Beanstalk is possible. It would have to stretch out so far to defeat gravity that it would hit so many satellites. That’s the first issue that pops to mind.
That’s not really much of a concern unless you aim satellites directly at it. There’s plenty of space in space.
Yeah, it’s not really satellites that are the problem. There’s so much debris in orbit from our space programs, it’s starting to form an entire layer around the planet. The risk of collision from this debris is constantly growing.
But there’s really not that much debris. Certain orbits can get packed but there’s plenty of availability. Also stuff in LEO deorbits pretty fast.
Kessler Syndrome. The worst part is that, at some point, the risk of collision becomes so great that the problem becomes self-perpetuating, further increasing the risk until we can’t leave Earth anymore.
Would it not be self-correcting in the end? The various bits of debris that form the Kessler cloud would collide so much that they would eventually fragment into little more than dust, or lose enough energy that they are no longer in a stable orbit?
There’s no appreciable drag up there, so if it’s in orbit it’s going to be in orbit for a while, regardless of how big or small it is. Is the amount of energy lost to ripping the debris apart enough to eventually de-orbit the object? I honestly don’t know. My immediate thought is no, barring outside factors, because if it did spacecraft would be torn apart during their de-orbit burns; but I honestly can’t get my brain around that well enough to be certain (maybe the longer time a spacecraft takes de-orbiting reduces the stresses that a piece of space junk suffers instantly).
The kind of crazy thing is that, if a 1,000kg satellite orbiting at an altitude of 36km and a speed of 11,000kph breaks into a thousand pieces, each of those 1kg pieces are still traveling at an altitude of 36km and a speed of 11,000kph.
Its not really how radiation work, radiation don’t move trough a tube and material don’t necessarily get radioactive from being irradiated, actually the cable would contribute stopping radiation, and radiation resistance is definitely something you need to consider in a space elevator material.
Induced radioactivity is mostly the result of contamination from radioactive materials. Whilst it’s possible to induce radioactivity from gamma rays directly, you’re talking “background noise” levels of radiation. Which is to say, the cable isn’t going to become notably radioactive, and even then, the part that does, will be the part that isn’t protected by the atmosphere. And for people to navigate those areas of space safely, we already need shielding to protect us from the suns electromagnetic radiation, so a small increase in radiation from the cable isn’t going to make much of a difference to anything.
you’d get baked like Marie Curie’s ovaries
It wasn’t just the ovaries, it was the whole Marie
(and Pierre too, but he died from an accident before the radiation could kill him)
And tbf, her ovaries worked fine for quite some time it seems - she had two daughters who both were exceptional people in their fields as well - one got a nobel prize in chemistry, the other was a Pulitzer prize nominee, fought the nazis, was a war correspondent, had role in the establishment of NATO and UNICEF and -as a representative of UNICEF and together with her husband received a nobel peace price for the organisation. The later one died in 2007,btw.
(The whole family is totally crazy,btw. Both on her sisters and cousins side, but also her daughters and grandchildren and now grandgrandchildren. Everyone excelled in their scientific field)
Compare that possibility to the radiation from sunlight. I wouldn’t worry about radiation, I would be more concerned about altering earths rotation, or damage caused if the space elevator were to collapse.
Yeah the dearth of destruction left by it falling would be insane. I assume it would have to be built along mainly west coasts to mitigate risks. But maybe it’s more important to be somewhere with less hurricane/cyclone risks, and with really stable bedrock obviously.
A space elevator is dominated by angular momentum and centrifugal force, not by Earth’s gravity. There’s no way for the cable to be pulled down to earth unless you strap rockets on it to slow it down, but even then that’s gonna cost a lot of fuel.
That scene in foundation was not accurate, if the cable snaps at some point it’s not going to magically decelerate from earth’s rotation speed to slow enough to be pulled down. The outer part will probably fly away and the inner part sort of hover in place.
Dearth means “a striking lack of,” as in “dearth of evidence.” (No evidence)
It was supposed to say “death and” autocorrect had other ideas I guess.
Its still funny to read this as you having a concern about the striking lack of distruction caused by space elevator collapse. Maybe the elevator debris all got thrown into orbit?
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By the necessities of its design a space elevator has to reach geostationary orbit, which would make it tall enough to wrap around the planet twice if it fell. Wouldn’t really matter if you built it on a west coast or not.
A geostationary orbit is ~35,000km from the surface of the earth. The circumference of the earth is ~40,000km.
And not all would fall. Part of it would be launched outwards by inertia.
Ah thanks, I was a dingus and looked up the diameter instead of the circumference. Still doesn’t really matter where you build it. No matter what it’s fucking up a a good portion of the equator if it falls.
It still can’t really fall. It’d be moving incredibly fast sideways. Fast enough to miss the Earth for a while. Geo stationary orbit is the point where orbital speed matches Earth’s rotational speed, so if it’s anchored at the ground, then it’s at orbital speed if at GEO. The higher the orbit, the slower the orbital speed. So using a higher orbit to maintain tension means it’d be traveling beyond escape velocity, held down by the cable. A break would release the mass into the solar system
I think that depends on how big the tether is tbh. It has to be usable as an elevator so it can’t just be a thin cable. And your scenario is assuming that it would be cut down near the base, if it’s damaged anywhere higher up anything below the cut will fall down to earth.
Yeah that’s kinda what I was envisioning, maybe half the tether zingin off into space when the other half fell into the pacific or desert, but even half is gonna be like 15,000km I guess.
Also wasn’t there a scenario like this in one of the Mars Trilogy books?
Actually, a good ways passed geostationary orbit if I remember correctly. It needs centrifugal force to keep the cable taut, since it won’t be supporting its weight from the surface.
Ada answered the question, but consider your question.
You said “leaving a spaceship with no suit”. If your idea is that something left in space becomes dangerously radioactive then any space station or space ship would itself become dangerously radioactive.
So the answer is, no, things in space don’t become dangerously radioactive. Also things in contact with radioactive substances don’t themselves become radioactive except under extremely specific circumstances. Your house didn’t become dangerously radioactive because of the radioactive americium-241 in the smoke detectors.
Any time you talk radiation, you need to be specific about what kind of particles, how much energy they have, and how much of it there is.
Most of the stuff in orbit is charged particles (electrons and small atoms) and low energy photons. Those get stopped by relatively thin layers of shielding, but if you’re not careful you’ll get cooked from raw heat.
Ionizing radiation like neutrons or x- and gamma-range photons can radioactivate materials, and take more shielding – think feet of water or a couple inches of lead. Nuclear reactors have that, but spaceships don’t. Fortunately unless you bring a reactor with you they’re rare enough that it’s not really necessary.
Substances become radioactive when they get hit by some kind of ionizing radiation and change into an isotope that itself emits radiation. Conducting radiation like a wick isn’t really a thing.
Electrons and small atoms are kinds of ionizing radiation when they’re flying around with enough energy. Also, it’s not the photonic type that makes something else radioactive (mostly). It’s the particles. Look up what neutrons are doing in nuclear reactors. They “contaminate” things that aren’t normally radioactive because neutrons ‘stick’ to their atoms and make the atom unstable because now it’s a different, most likely less stable isotope.
We have a free eternal source of energy.
It’s called solar.If a space elevator became a reality, the real problem would be that it can get destroyed easily by terrorists or even just a defective satellite in low earth orbit crashing into it.
And then you have a 20000 mile long cable wrapping around earth at supersonic speeds.Oops we accidentally cut earth like a big wheel of cheese
If a space elevator happened, I would certainly make sure I don’t live in its flattening path around the equator
wouldn’t it be a 125–250 mile cable tops?
No, the upper end needs to be in geostationary orbit, which is at a distance of 35786 km (22236 miles).
Otherwise the cable will just wrap around the equator as soon as you launch it.
And even if you used a rigid rod instead of a cable, spacecraft released at the end would just fall back to earth cause at that low altitude it doesn’t rotate with escape velocity.How do you anchor the end in space so that you don’t just retract the cable every time you try to use it?
That’s the neat thing about geostationary orbit. If the station at the upper end has enough mass, its own centrifugal force keeps it anchored in its orbit.
It’s passed geostationary orbit. Geostationary orbit is balanced, but it needs centrifugal force pulling out. So, you need to be going faster than the orbit wants, hence, further out.
Except that you would drag it out of geostationary orbit every time you used it? Like no matter how heavy it is your still moving it closer every time you pull on the cable. You would need to constantly thrust equivalent to the mass of the cable and whatever the cable is pulling. At that point aren’t you still basically just launching shit?
The more you think about it the dumber it gets. You would need to constantly move reaction mass to to the platform to create that thrust, but you’d have to use that thrust to counter the mass that you are bringing up. It’s all the same problems as conventional rocketry.
The way a normal elevator works is one way to lessen the problem: the port on the top is used to launch cargo AND to receive it, so when you make the outgoing cargo rise you use the incoming cargo as the balance. 1 ton goes up, 1 ton goes down.
Assuming it isn’t intended to return to earth at terminal velocity the station will ALSO need to bear the mass of arresting its descent, so no, that wouldn’t do much.
Think of earth as a rotating bowling ball, with a string attached, and a tennis ball attached to the other end of the string. The craft you launch is an ant walking along the string.
Its legs push against the string, but that’s nothing compared to the rotation of the bowling ball that keeps the string tight.
Technically, the ant’s climbing will slow down the rotation of the bowling ball over time, but this won’t have a noticeable effect for many millennia.Right, except that a bowling ball weights about 6kg and a tennis ball weighs about sixty grams, so we would only need to build a platform that weighs 1% of the total mass of earth.
If you figure that out give NASA a call, they’d be real interested.
I think I read somewhere that we do have the technology to create a Dyson sphere but it would be too much of a massive undertaking time and labor-wise at our current level.
We have the technology to manufacture materials that could make up a Dyson Swarm. We are not even close to having the technology to make materials that would be sufficient to make a Dyson Sphere.
What we don’t have is the resources, logistics, energy supply and manufacturing base to implement either…
Not Dyson sphere (also a sphere is literally impossible), though maybe space elevator. If we weren’t already so close to Kessler Syndrome, anyways…
We do not. We can’t even move solar energy from earth orbit down to earth at any scale that would be economically viable or really even useful.
We lack the material science to build something that large but still light enough to be physically stable AND somehow collect and transmit energy.
We also lack the technology to stop it from being destroyed by space debris even if we could somehow build it.
There isn’t a requirement for a Dyson shell to transmit energy. You could just envelope the sun in habitats that use the energy they collect locally and that would meet the criteria of a Dyson shell (and a K2 civilization).
Sure but that’s even harder!
It requires more material and financial resources, but isn’t necessarily harder. Transmitting energy effectively to reduce heat, or managing the excess heat starts running into some pretty tough limits of physics. Most of the issues with spinning habitats are engineering problems within the capabilities of our current technology level and materials science. It’s just super expensive and has terrible ROI for now.
The trick with a space elevator is that the cable needs to be very thin. The material needs to be strong. That’s just two reasons why we’re still far from putting that to any real use.
I don’t think having a small line through our atmosphere will slowly poison us. The extra radiation that would make it through is probably a rounding error. The material would have to be such that it doesn’t attract radiation. And even if we discovered that this could be a problem, if we have become smart enough to build this space elevator, we’ll probably be smart enough to figure out a way to filter it out.
No extra radiation would make it through because that’s not how radiation works.
