Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Dyson spheres

  1. Jul 27, 2005 #1
  2. jcsd
  3. Jul 27, 2005 #2
    no. they are to inefficient and would take more matter than there is in the system to build, iirc
  4. Jul 27, 2005 #3


    User Avatar
    Gold Member

    Larry Niven's 'Ringworld' idea is far more interesting, and probably easier to produce.
  5. Jul 27, 2005 #4
    What do you mean inefficient, currently earth receives only one billionth of the sun's energy. With a Dyson sphere we would be able to collect nearly one hundred percent of the sun's released energy. Also if we used the asteroid belt as a source we would have ample material.
  6. Jul 27, 2005 #5
    how would it collect all of that energy?
  7. Jul 27, 2005 #6
    A Dyson "bubble"—has been proposed in which the shell would be complete, very thin, and non-rotating. It would consist of statites, or stationary solar sails, which reflected light onto collectors for use in external habitats. The entire mass of the structure would be approximately that of the Moon or a large asteroid.

    Did you read the article?
  8. Jul 27, 2005 #7
    that is a vast underestimate for the mass
  9. Jul 27, 2005 #8
  10. Jul 28, 2005 #9
    I agree about the underestimation. Plus, it'd have to be a specific material. Hey, here's an idea, let's use our iron core! Joking aside, What's more plausible, but still way off is a much smaller -belt- of solar cells within mercury's orbit, rather than this vast... Thing. Even that takes up more silicon than is available. Any people from the Nulcei and Particles forum wanna help make some?
  11. Jul 31, 2005 #10
    I believe the Dyson Sphere is possible. We need to have full blown nanontechnology to reproduce the building materials such as the particles in space and the other matters in our solar system and convert them into something dense like diamond. The whole structure would be built out of diamond created from the particles in our solar system. Full blown nanontechnology can do this. We would then be a class 2 civilization when its all said and done.
  12. Jul 31, 2005 #11
    lets make some quick calculations. [tex]M=90000000000000000(\pi)(thickness)(density_{material used})[/tex]

    and it has to be at least so thick or it won't hold
    Last edited: Jul 31, 2005
  13. Jul 31, 2005 #12


    User Avatar

    Staff: Mentor

    But so what? What does that do for us? Right now, a solar cell 300km by 300km would pretty much cover all our energy needs.

    Quick calculation on amount of material were talking about: the suface area of a Dyson sphere would be about 2.8 E17 square km. At a hundredth of a mm thick (for a mylar-like solar collector), that's 2.8E9 km^3. The volume of the moon is 2.1 E10 km^3. So that's 1/10 the volume of the moon. But that doesn't include the structure needed to hold sections of it flat and pointed at collectors.

    The other types of Dyson spheres would use far more material and would not be possible, much less feasible any time in the next few milenia.
  14. Aug 1, 2005 #13
    wouldn't a sphere like that act like a big solar sail in every direction? solar wind would push the mylar-like foil thingy against the frame and i would think it would eventually tear....not to mention comets, micrometeors, and all the other little things that would rip a gaping hole in it. even if we had enough mass in our system to make a strong, stable dyson sphere, most of it wouldn't be usable. you can't really make a dyson sphere out of gas.
  15. Aug 1, 2005 #14
    It's all possible m8. Even Einstein said that all things are possible with imagination. We just need nanontechnology to be fully developed. Advanced Nanotechnology can basically transform any material into anything else and nanotechnology has the ability to reproduce and make limitless copies of that material.

    You know how many particles there are in the volume of our entire solar system? There's more than enough building blocks to convert required for the Dyson Sphere. Diamond would the ideal converted material for the exterior shell of the entire Dyson sphere because it is dense and extremely durable. The inner shell would be composed of solar cells.
  16. Aug 1, 2005 #15


    User Avatar

    Staff: Mentor

    Well sure, if you assume anything is possible, then anything is possible. That's redundant and meaningless. I hate to break it to you though: not everything is possible. We are constrained by the laws of science and physical reality.
    I don't know where you get that idea. That doesn't sound like nanotechnology to me, that sounds like Star Trek replicators.
  17. Aug 1, 2005 #16
    Your type of response is just as or even more redundant, predictable, and meaningless to a statement like mine. I believe everything is possible. We just haven't explored every aspect of physics and quantum physics yet. We are only constrained to the limits of our discoveries so far. We only think in 3 dimensional terms and we are only infants in this vast universe thinking we are so experienced in knowledge. We still have a long way to go, experts like you, or students like me, we are all the same. We are nothing more than pupils in this school called reality.

    There are infinite things to learn. The concept of infinity itself is beyond comprehension and we can only (as of now) represent it with a sideways "8". For example, we still don't know what is the energy source for gravity and all other types of energy. We only know how they work, but what are their energy sources? We are still unsure as to what dark energy and dark matter are.

    The only obstacle in mankind's way is his arrogance of the limited knowledge that he has accumulated thus far, making him closed-minded to unconventional ways of thinking. The fact that we can imagine things that aren't consistent with the "laws of physics" shows the unlimited potential we really have. We just haven't been able to tap (at least not yet) into that realm of higher logic.

    Last edited: Aug 1, 2005
  18. Aug 1, 2005 #17


    User Avatar

    Staff: Mentor

    I'm sorry, but that attitude is incompatible with science.
    You need to recognize that "unconventional ways of thinking" are still going to be constrained by the laws of physics.
    No, all that shows is that humans are capable of writing good fiction.

    Let me give you an example: I can imagine a universe with a different gravitational constant. In it, I can jump so high I can jump over buildings. How does my imagination of it help make that universe a reality?

    Or how about imagining a universe where a=fm instead of f=ma? What does that do for us?
    Last edited: Aug 1, 2005
  19. Aug 1, 2005 #18
    It might be incompatible with our limited understanding of science. But who's to say that all of science (I'm referring to all the unexplored areas of science) has been explored? Isn't the mindset of an explorer the best attitude for scientists, no? Or should scientist remain closeminded and satisfied with current physics only? o_O

    No. Unconventional ways of thinking are only constrained by how much of what we know of physics today. Are you saying that we have explored all of physics? That's why its still called "uncoventional", because it doesn't agree with current physics. But when we expand our thinking annd explore the greater unknowns of all of science, you never know, it might just become conventional, no? o_O

    Oh well, I'm only 16. You are probably wiser than me by a long shot. You could be right of course and I could be wrong..... :uhh:
  20. Aug 1, 2005 #19


    User Avatar

    Staff: Mentor

    No one is saying that all that there is to discover has been discovered. You're misunderstanding the problem.
    A scientist should be open minded, but should also understand that there are limts to what we can do. We are not omnipotent.
    No, I'm not saying that. You're misunderstanding the problem with what you are saying.

    Science is like a building. One floor is built on top of the previous. It is extremely rare that more than a small fraction of the floors are knocked down to be replaced by new floors. Ie, no amount of future scientific investigation is going to change our understanding of f=ma, for example. And we never, ever knock the whole thing down and start from scratch.

    Some of the things that you are proposing would actually require our existing knowledge to be wrong - not just incomplete. That simply isn't possible. For example, if you use an accurate scale to measure the mass of an object, you'll get, say, 1.0001 kg. No amount of future analysis of that object will yield a mass of 1000 kg.
    Last edited: Aug 1, 2005
  21. Aug 1, 2005 #20
    I have to agree with you man. You got me there. Thanks for that input. :smile:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Dyson spheres
  1. Polarized sphere (Replies: 0)

  2. Insulating sphere (Replies: 1)

  3. Drag and spheres (Replies: 3)

  4. Force on a sphere (Replies: 3)