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Dyson sphere, a concept coined by the physicist Freeman Dyson, is a solar megastructure built around our Sun to harvests most of the radiated energy from it.

While this sounds impossible for now, some of its variants look promising in the near future, for example a Dyson swarm or a Dyson bubble around the Sun.

Do we have the technology to do that?

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  • $\begingroup$ I think material engineering is not quite at the point that we could achieve this yet. Building a space elevator is a lesser task, but even that is ~50 years out of our reach. $\endgroup$ – extropic-engine Jul 16 '13 at 21:31
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    $\begingroup$ No. Nice and simple. $\endgroup$ – geoffc Jul 16 '13 at 22:05
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    $\begingroup$ There's also the question of demand, in relation to investment. Because it is that which is profitable which is doable, you don't need to wait for people to make profits. In the very long run the Sun fuses so much mass that it is The big source of energy. But for some time we may do well with nuclear power from the materials on our tiny Earth. $\endgroup$ – LocalFluff Nov 1 '15 at 4:09
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For a solid sphere - Absolutely not!

This calculation from http://www.aleph.se/Nada/dysonFAQ.html explains why:

8) How strong does a rigid Dyson shell need to be?

Very strong. According to Frank Palmer: Any sphere about a gravitating body can be analysed into two hemispheres joined at a seam. The contribution of a small section To the force on the seam is

$\mathbf{g}\text{(ravity)}\cdot\mathbf{d}\text{(ensity)}\cdot\mathbf{t}\text{(hickness)}\cdot\mathbf{A}\text{(rea)}\cdot\mathbf{cos}(\text{angle})$.

The integral of $\mathbf{A}\cdot\mathbf{cos}(\text{angle})$ is $\mathbf{\pi}\cdot\mathbf{R^2}$.

So the total force is $\mathbf{g}\cdot\mathbf{d}\cdot\mathbf{t}\cdot\mathbf{\pi}\cdot\mathbf{R^2}$. Which is independent of distance, neatly enough.

The area resisting the force is $2\cdot\mathbf{\pi}\cdot\mathbf{R}\cdot\mathbf{t}$.

Thus, the pressure is $\mathbf{g}\cdot\mathbf{d}\cdot\mathbf{R}/2$; this can be translated into a cylindrical tower of a given height on Earth. If that tower built of that material can stand, then the compression strain is not too great.

At 1 AU, that comes to $2\cdot(\mathbf{\pi}\cdot\text{AU}/\text{YR})^2$, or -- by my calculations -- in the neighborhood of 80 to 90 THOUSAND kilometers high.

For the thin version held up by solar wind and photon pressure - nope. The numbers are better but still out of our reach.

For the swarm of independent solar panels - yes. We would just need to build a hell of a lot of them - might need to take apart a small planet for raw materials though...

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    $\begingroup$ 80 to 90 MEGAMETERS! Hehehe... I've always wanted to use "megameter" for something. $\endgroup$ – Magic Octopus Urn Jul 5 '18 at 17:34
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We definitely could not build a Dyson sphere with current technology.

The first problem is a lack of material. To build it at any reasonable distance from the sun, the volume of even an extremely thin shell is greater than all the planets, plus the asteroids, and the Oort cloud.

After that problem, one has to move all the mass to the shell. That is a huge amount of energy.

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