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Space generators by temperature difference?

  1. Dec 11, 2012 #1
    This is another theoretical question post of mine.

    I read somewhere that there is a huge temperature polar opposite change in space just from shielding ie shadow vs. exposed to sun.

    That was because of the absence of an atmosphere or "stuff to keep the heat"

    So, pulling numbers from the air, it was like 300C or -200C if it was exposed to the sun or in the shadow.

    I was wondering if one were to build generators with spinning gates (open/close) to let in light then not let in light.

    Could you build generators from temperature change?

    There is the added benefit of no gravity or little anyway

    I apologize if I am missing major concepts, I failed thermodynamics after I got into the statistical portion which is not an excuse I basically temporarily lost interest in the subject and did not study.

    So perhaps my questions may be deemed unworthy but just for the hell of it, I'd like to ask you guys your thoughts.

    Also just to throw it in there

    How much "scrap atoms" are there in space

    Could you "capture them" in the void blackness of space?

    I'm interested in gathering oxygen molecules and such from the outside and then processing them inside for use in life support and what have you.

    Is there "nothing" besides dark matter/energy in space? Unless it is in a planet, nebula or galaxy?
  2. jcsd
  3. Dec 11, 2012 #2
    I believe they already do use these thermocouple generators in space. If not from the sun, then from the heat of a nuclear battery.

    There aren't very much atoms in space (I don't know exactly how many, but I believe less than in an ultra-high vacuum). There's plenty of oxygen on board a spaceship. The problem is that it combines with other elements as we breathe. However, as long as we don't throw these compounds overboard we can recycle them by breaking them apart again. That's what life support systems already do. It's surely a more efficient way than trying to capture the almost negligible atoms present in space.

    Although, the concept has been suggested for powering super-fast spaceships (see Bussard ramjet). I guess the idea was that if going close to the speed of light, even the minute molecules present can be harnessed for some form of space-jet engine. Still, the concept involved using kilometer or thousands-kilometer scoops. It was meant to work in interstellar space, which is even more void than close to earth, but still...
  4. Dec 11, 2012 #3


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    Indeed. Voyager spacecraft are powered by these. So these have been used in space at least since the 70s.
  5. Dec 14, 2012 #4
  6. Dec 14, 2012 #5


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    Solar panels and thermocouples are more reliable since they have no moving parts.
  7. Dec 14, 2012 #6


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    The density of gas in space varies. Near stars and nebulas you generally have a much higher density compared to intergalactic space. (But still very very very low compared to Earth's atmosphere)

    See here: http://en.wikipedia.org/wiki/Outer_space#Environment
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