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The Dyson Swarm is common in sci fi as an energy source, and sometimes also as a powerful weapon. As it is commonly understood, it harnesses the energy of the sun, which stores a vast amount of energy. A Dyson Swarm is necessary for any civilization to be deemed Level I or II on the Kardashev Scale.

However, I quickly realized a small flaw in this design: it is not stated how the energy from the sun could be transferred to the planets whose civilizations need it, especially our Earth.

I believe that this issue should be resolved for the concept to truly work. Therefore, I ask, if Dyson Swarms could even be created, how would the stored thermal and light energy be transferred to respective planets?

PS: Thanks for people pointing out that Dyson Spheres are habitats, not just energy collectors for planets.

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  • $\begingroup$ Do you mean a Sphere or a Swarm? A Sphere wouldn't send anything, it replaces the Earth. The segments of the Sphere are the habitats. The Swarm (the arguably more scientifically plausible Dyson construct) would have to transmit the energy. $\endgroup$ Feb 4, 2020 at 5:35
  • $\begingroup$ Out of 4 fundamental forces only gravity and light have infinite range, having said that gravity is extremely weak so we are left with light particularly laser because it is cool. Gamma ray is dangerous for spaceships and ground forces while radiowave is for streaming porn so we take the mid range of spectrum such as microwave... $\endgroup$
    – user6760
    Feb 4, 2020 at 7:03
  • $\begingroup$ What would be the purpose of such transmission? Total obliteration of the Earth? $\endgroup$
    – Alexander
    Feb 4, 2020 at 8:19
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    $\begingroup$ Any civilization with even 1% of 1% of a Dyson sphere is no longer a planet bound one. They will inhabit a variety of space habitats instead. Some people are talking about how power will be beamed back. That is impossible. Yes, power satellites are something some people are talking about. But the Earth only has a limited ability to get rid of waste head (by radiating it into space). If you send back anything but a tiny part of a Dyson Sphere's energy, you are going to melt the Earth, or at least boil off the oceans and atmosphere. $\endgroup$ Feb 5, 2020 at 2:20
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    $\begingroup$ *Kurzgezagt entered the chat* $\endgroup$
    – Möoz
    Sep 9, 2020 at 5:00

6 Answers 6

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EM Radiation

  1. Collect energy
  2. Use energy to shoot lasers towards Earth
  3. Use dish antennas to catch laser energy
  4. ???
  5. Profit

Don't believe me just because I'm saying this. NASA and JAXA have made some baby steps in that direction. And anyway any Dyson sphere that sends its energy elsewhere is based on this idea.

Also, don't worry about dying from being shot with space lasers. The wiki article linked in the paragraph above says:

Contrary to appearances of SBSP in popular novels and video games, most designs propose beam energy densities that are not harmful if human beings were to be inadvertently exposed, such as if a transmitting satellite's beam were to wander off-course.

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    $\begingroup$ This is the correct answer, afaik. It's basically solar power satellites on steroids. The hard part is getting high enough efficiency to justify it, since each step of the process loses some. The ideal antenna for such things would probably qualify as a minor megastructure, or need to piggyback on one. IIUC, the best we've got atm is to convert to Microwaves for beaming to the ground? $\endgroup$
    – CAE Jones
    Feb 4, 2020 at 8:06
  • $\begingroup$ Giant Death Lasers from Space. Nice way to end humanity at the touch of a button. $\endgroup$
    – ths
    Feb 4, 2020 at 9:32
  • $\begingroup$ @caejones microqaves are indeee the preferred frequency range, Jaxa has done experimentation on that. $\endgroup$ Feb 4, 2020 at 12:51
  • $\begingroup$ @ths from the article in the link: "Contrary to appearances of SBSP in popular novels and video games, most designs propose beam energy densities that are not harmful if human beings were to be inadvertently exposed, such as if a transmitting satellite's beam were to wander off-course." ;) $\endgroup$ Feb 4, 2020 at 12:54
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    $\begingroup$ @ths - if you're transmitting enough power to Earth to qualify as a Giant Death Laser, you're probably doing it wrong. Unless the goal is to create a Giant Death Laser. $\endgroup$
    – jdunlop
    Feb 4, 2021 at 22:48
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You've missed the whole point of a dyson sphere

There are no planets to transfer the energy to. A dyson sphere would have a living space equivalent to around 550,000,000 times the surface of the Earth.

The variant of the Dyson sphere most often depicted in fiction is the "Dyson shell": a uniform solid shell of matter around the star. Such a structure would completely alter the emissions of the central star, and would intercept 100% of the star's energy output. Such a structure would also provide an immense surface that many envision would be used for habitation, if the surface could be made habitable.

See Dyson Sphere

Virtually every last piece of mass in the solar system would be required to build the sphere so Earth, Mars, Venus and even Jupiter would be mined, refined and used to build the sphere. Quite possibly we'd have to raid nearby solar systems for more materials.

Finally you wouldn't want to be outside anyway as there is no longer a sun for the planet.

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    $\begingroup$ Okay, I meant swarm, that which transfers the collected energy back to neighbouring planets. $\endgroup$ Feb 4, 2020 at 6:57
  • $\begingroup$ Even the shell could have a gap or arrangement of mirrors for the planet's sake. The only issue with that would be that, over millions of years, it might alter the star's trajectory. But realistically, a swarm of habitats and satellites just makes far more sense than a shell (economics, the customization of the separate habitats, finding the materials, territorial claims, adjustments after construction, etc). $\endgroup$
    – CAE Jones
    Feb 4, 2020 at 8:01
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    $\begingroup$ I think one can have the Dyson swarm/sphere concept at very different levels of technology. Having a couple of satellites with large solar panels orbit around the sun is almost possible with current technology. This requires transmitting the collected energy to somewhere where it is used, most likely earth. Building a full dyson sphere is technologically massively more advanced but doesn't require transmission any more. $\endgroup$
    – quarague
    Feb 4, 2020 at 10:00
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Synthesize antimatter in space.

Transmission of power is near future SF and well and good; yes, yes. Goldeneye and all. Tesla.

Another option would be to lock the energy into a portable form and bring chunks of it home. This is akin to liquefied natural gas or other concentrated energy sources that are more portable and less dangerous for being concentrated.

The most concentrated fuel would be antimatter. Space is a good place to be fooling around with antimatter because of the go boom prospects. Operating according to E=mc2, raw solar energy is turned into antimatter. Antimatter pellets in their magnetic bottles are stored in space then ferried down to earth on an as needed basis to power generators.

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enter image description hereYou do not need wires to transfer power. See this article: https://en.wikipedia.org/wiki/Wireless_power_transfer

The interesting thing about transmitting power from space is there is no nighttime down-time. The power station just needs an orbit where it can transmit to the groundstation as the planet spins.

The red circles are space based power zones for my space game.

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    $\begingroup$ Can you be more specific? As written, this seems like a link-only answer, which we try to avoid. You specify that wires aren't needed, but you don't detail a specific alternative besides "transmitting" power. $\endgroup$
    – Zxyrra
    Feb 4, 2020 at 3:55
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A simple one would be to use an orbiting swarm of mirrors.

The angle of the mirrors could be adjusted to reflect 'natural' sunlight towards earth, where it could be captured for use.

This would be the simplest method, as the satellites would be relatively easy to manufacture so you could mass produce them. They would also be simple to operate and have little to no maintenance - if it was a mirror all you need is a way for it to rotate (perhaps a gyroscope) to reflect light.

An onboard computer (or centralised computer if you don't want complexity in each one) could calculate the optimum angle to maintain altitude, positioning and trajectory to ensure the swarm is stable. The reflection of the sunlight would change the satellites trajectory, and balanced with gravitation forces, and thus needs to be coordinated.

If the radius of the swarm is roughly the same orbital distance to Earth, it is conceivable that almost all of the sunlight from the Sun could be diverted to Earth. If they are closer to the Sun you may need to get complex and reflect light of other satellites to then reflect it onward to Earth.

This naked sunlight would be then converted to useful energy at a focal point either on Earth (which would likely not be good for Earth) or near Earth (perhaps L1) where it could superheat mass to generate power, fuse atoms or other methods of power generation from extreme concentrated heat and radiation.

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    $\begingroup$ " almost all of the sunlight from the Sun could be diverted to Earth"... aaaaand... this is seen as a good thing? Why do you want to Alderaan the Earth? With the full output of the sun reaching earth, you will have completely evaporated the whole planet in 4 hours. Down to the very core, with every single atom of it given enough heat energy to reach solar escape velocity. pouf no more Earth. Not even a dust cloud will remain, just a whiff of iron ions wafting past the oort cloud. $\endgroup$
    – PcMan
    Feb 4, 2021 at 21:25
  • $\begingroup$ @PcMan "With the full output of the sun reaching earth, you will have completely evaporated the whole planet in 4 hours." - nop, about 7 days, in practice even more, significantly more, orders of magnitude more. but yeah life will end in less than 24 hours, lol $\endgroup$
    – MolbOrg
    Feb 5, 2021 at 0:51
  • $\begingroup$ @MolbOrg do the calculations. remember that the sun outputs 3.9e26 watts. Earth only masses 6e24kg. so enough energy input to heat every piece of Earth by 65 watts per kilogram. For iron, 1 degree warmer per 6 seconds. After "about 7 days" every molecule of the planet's mass would be at more than 100 000 Kelvin. No, I don't think the planet will stick around that long! $\endgroup$
    – PcMan
    Feb 5, 2021 at 6:39
  • $\begingroup$ @PcMan i did, pretty much close at the beginning, I should have done it through binding energy, but for some reason I didn't, venus is similar to earth. Also, u missing one of the optics law about the impossibility of just focusing sun energy to heat something more than it surface temperature, so as u do not include heat dissipation by a planet. it seems with me u always start by saying "do the calculations.", u probably should remember by now - I do them before I say things, I can make mistakes, but I'm pretty sure about this one. $\endgroup$
    – MolbOrg
    Feb 5, 2021 at 22:04
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As far as I can find, no one has taken on the concept that you can't actually beam all that energy to the earth without turning the earth into an ant under a magnifying glass. Harnessing wind or solar power doesn't change the energy on earth, we're just moving it to motors and microprocessors where its heat moves back to the atmosphere. But if you somehow beamed all the energy of the sun to the earth, we would also need a corresponding method to gather and beam all the excess heat back into space so we wouln't burn the planet to a crisp.

I find it much more likely that we would be harvesting the energy from the earth's core well before we tried to gather it offworld from the sun.

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