Comment by tlb
13 hours ago
What do you think the limiting factor is? I don't see why we can't scale manufacturing of satellites up as far as we want. If we mine out a substantial fraction of the mass of the earth, we can go harvest asteroids or something.
>> Dyson Sphere
> What do you think the limiting factor is?
You need to be able to harness enough raw material and energy to build something that can surround the sun. That does not exist in the solar system and we do not yet have the means to travel further out to collect, move, and construct such an incredibly huge structure. It seems like a fantasy.
The inner planets contain enough mass to create a shell of 1 AU radius with mass of 42 kg/m^2. That sounds like a plausible thickness and density for a sandwich of photovoltaics - GPUs - heat sinks.
You don't build a rigid shell of course, you build a swarm of free-floating satellites in a range of orbits.
See https://www.aleph.se/Nada/dysonFAQ.html#ENOUGH for numbers.
I am dying to know where you’ll get the energy and manufacturing scale in order to achieve this with current, or current+50-years technology.
Do tell.
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Great. Now run the numbers to find the energy required to disassemble the planets and accelerating the pieces to their desired locations. For reference, it takes over 10 times of propellant and oxidant mass to put something in LEO.
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Also it's gravitationally unstable, like Dyson Rings, where as soon as you have any perturbance from the center means that the closer side is more attracted to the sun so it enters a feedback loop.
There are only so many people who can make satellites; there are only so many things to make satellites out of; and there are only so many orbits to put them in. There are only so many reasons why a person might want a satellite. There are only so many ways of placing satellites in orbit and each requires some amount of energy, and we have access to a finite amount of energy over time.
Finally, if we limited ourselves to earth-based raw materials, we would eventually reach a point where the remaining mass of the earth would have less gravitational effect on the satellite fleet than the fleet itself, which would have deleterious effects on the satellite fleet.
Seven reasons are intuitive; I’m sure there are many others.
People can build a factory that makes satellites. And then a factory that makes factories to make satellites.
There is plenty of material in the solar system (see my other response), and plenty of orbits, and launch capability can scale with energy harvested so the launch rate can grow exponentially.
Lots of people will probably decide they don't want any more satellites. But it only takes a few highly determined people to get it done anyway.
>Just imbest[1] and it will grow exponentially.
That's how that argument sounds like, particularly when you hear it from someone who is as broke as it can be.
It's easy to type those ideas in a comment, or a novel, or a scientific paper ... bring them to reality, oh surprise! that's the hard part.
1: The dumb version to invest
> Finally, if we limited ourselves to earth-based raw materials, we would eventually reach a point where the remaining mass of the earth would have less gravitational effect on the satellite fleet than the fleet itself, which would have deleterious effects on the satellite fleet.
The Earth's crust has an average thickness of about 15-20 km. Practically we can only get at maybe the top 1-2 km, as drill bits start to fail the deeper you go.
The Earth's radius is 6,371 km.
So even if we could somehow dug up entire crust we can get to and flung it into orbit, that would barely be noticeable to anything in orbit.
Once you dig up the top kilometer of a planet's crust, what's under your feet? The next kilometer!
That would suck to do to Earth, but we can launch all of Mars's mass into the swarm.
After a few decades, you need to start replacing all the solar panels.
And the robot army being used to do the construction and resource extraction will likely have a much shorter lifespan. So needs to be self-replicating/repairing/recycling.
The physical amount of material in the solar system is a pretty big limiting factor.
Yeah, but besides not having the physical amount of material available in the solar system, or the availability of any technology to transfer power generated to a destination where it can serve a meaningful purpose in the foreseeable future, or having the political climate or capital necessary for even initiating such an effort, or not being able to do so without severely kneecapping the habitability of our planet, there are aren't really any meaningful barriers that I can see.
Are you suggesting that beggars would ride, if only wishes were horses!?
In 2026? Grift.