Eli5: What facts are holding humanity back from creating a Dyson sphere in reality?
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1) We don’t know how to build something on that scale in space. Building stuff in space is hard and a Dyson sphere would be the single biggest engineering challenge in the history of man by several orders of magnitude. We don’t even know where to start yet.
2) We don’t have the technology to efficiently launch all of those materials into space. Rocketry is still a nascent science and we are limited in how much we can launch at any point in time.
3) We don’t have the funding. At its cheapest, it costs $3k/kg to get something into space (more to get it positioned like it would need to be for a sun). That seems cheap, but a Dyson sphere would be beyond huge, and would likely cost trillions in launches alone, which says nothing of the cost of the technology itself. The ISS cost more than $150B – a Dyson sphere would likely far exceed global GDP to build it.
We lack the amount of materials to make a Dyson sphere. We lack the engineering knowledge and know-how to make a Dyson sphere. We lack the ability to travel to the right orbit to make a Dyson sphere.
Honestly, we’re about six tech levels out from a Dyson sphere. What this means is we lack the tools to make the tools needed to make the tools needed to make the tools to make the tools to build a Dyson sphere.
We understand the concept of a Dyson sphere, but we’re at least a thousand years away from being able to attempt one.
Scale mostly. We haven’t mastered long term outer space living. In order to construct something that large we’d need to be capable of functioning in space for generations of resource harvesting, conversion and construction.
There’s no reason to build one.
A Dyson sphere is a theoretical next step after we do as much as we can on Earth and decide we want even more. Building stuff in space is expensive, it only makes sense to do so if there’s some need for it. And so far there’s more than enough room on Earth for lots and lots of solar panels that are far cheaper to build and maintain on the ground.
Besides that, a Dyson sphere would involve absolutely amazing amounts of material use — you’re talking about taking apart planets to make the sphere out of them.
Funding. Even the biggest space programs don’t get much funding, proportionally speaking. It would require more money than we’ve ever spent on anything in space to get that going. A Dyson Sphere would have to be huge–many orders of magnitude bigger than anything we’ve ever built.
It would also be completely inefficient to have to launch all the requisite parts into space, so first we’d have to figure out how to build things in space, and ideally how to harvest the materials directly from space (maybe from the Moon, somewhere easier to launch from) so we don’t have to launch those either. Unless we can circumvent the problem by building a space elevator or something like that, but that’s a whole new source of difficulties.
Dyson spheres are orbitally unstable. They look interesting but they won’t “work” fundamentally (unless there are HUUUGGE engines that can correct unstable orbits).
There is no known material that has sufficient tensile strength (and orbit/rotate fast enough to generate 1G) to construct it with.
The material required to make one would consume all of the mass of all of the stuff in the solar system if the sphere would be anything thicker than a few meters (roughly). That is a lot of stuff.
That is assuming we have the energy harnessing capability to even get it started
Where would we stay while we built one?
Why would we need one in the first place? By the time sufficient technology is available to do this, we might as well terraform Venus and Mars – far “simpler” and certainly more redundancy. The “habitable” ring of a Dyson sphere would fit many quadrillions of people very easily – we’re not likely to get there.
Fundamentally, everything everyone else has said AND Dyson Spheres don’t actually work in practice from an engineering perspective UNLESS you could build the whole thing essentially instantly. Orbital mechanics is a serious and complicated process that has to be taken into account during the building process (even assuming all of the other factors are taken care of) and, at some point, the stuff you put into space to build the thing will either a) fall into the sun, b) fling itself out into space, or c) begin colliding with the other stuff up there that you’re trying to attach to it.
Auch better and actually possible construction is a Dyson Swarm or a Niven Ring, but both of these also have their 6-levels of tech problems along with other issues…
People have already mentioned a lot of good points, but one of the largest constraining factors is the amount of materials you would need. It would require an entire planet’s worth of resources (maybe even multiple planets depending on the planet’s size) which is a scale of engineering that is unimaginable right now.
Check out a show called ‘Science and Futurism with Isaac Arthur’ on YouTube or as a podcast, where they regularly discuss the logistics and feasibility of futuristic megastructure projects like this. (Case in point, this episode all about Dyson spheres – https://youtu.be/HlmKejRSVd8)
Nothing really technologically. In terms of collecting power, beaming it to earth, and keeping solar panels in orbit it is actually fairly basic technology that we already have.
However you would need to dismantle literally the entire solar system just to get enough materials to build something that big, we lack the infrastructure to build in space, we don’t currently have a need for that much power and we would struggle to maintain Earth’s orbit once we start pulling apart other planets.
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