# 2 civs per galaxy?

**URL:** <https://boards.straightdope.com/t/2-civs-per-galaxy/164997>\
**Category:** Great Debates\
**Created:** [March 29, 2003, 7:28am UTC](https://boards.straightdope.com/t/2-civs-per-galaxy/164997 "2003-03-29T07:28:08Z")\
**Posts on this page:** 5\
**Page:** 2

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**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\
**Post date:** [March 30, 2003, 5:48am UTC](https://boards.straightdope.com/t/2-civs-per-galaxy/164997/21 "2003-03-30T05:48:03Z")

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Yes, remember that the star is still radiating insidethe dyson sphere, so one of fourthings must be happening:  
the energy must all be radiated after processing (i.e. after the computer concerned has used the energy to transform its internal data as far as is possible;  
or  
the dyson sphere (actually a non rigid swarm) would increase in temperature;  
or  
the swarm could expand in volume due to Boyles Law;  
or  
the energy could be stored in a non-volatile form such as matter-antimatter pairs (difficult to acheive in practice, AFAIK).

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**Author:** ![elfkin477](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@elfkin477](https://boards.straightdope.com/u/elfkin477)\
**Post date:** [March 30, 2003, 6:49am UTC](https://boards.straightdope.com/t/2-civs-per-galaxy/164997/22 "2003-03-30T06:49:49Z")

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> [@](#):
>
> \*Originally posted by Sam Stone \*  
> \*\* Given the huge number of stars even in our local neighborhood, the total lack of signs of intelligence we’ve discovered so far is pretty baffling. \*\*

If you look at it that way it is baffling, but if you consider the possibility that the other planets have intelligent life, and may have access to our TV satellites-meaning they’ve seen the reality shows and news networks-they could just be avoiding us. What intelligent lifeform wouldn’t?

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**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\
**Post date:** [March 30, 2003, 6:55am UTC](https://boards.straightdope.com/t/2-civs-per-galaxy/164997/23 "2003-03-30T06:55:59Z")

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eburacum45: Yeah, that’s why I asked about ‘black-body radiation’. I assume a Dyson Sphere would radiate, but not nearly as much as the star inside. Plus, because the Sphere is much, much bigger than the star, the surface temperature would be much lower. So maybe a Dyson sphere would look like a big hole in space, radiating at a low enough temperature to not be easily visible.

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**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\
**Post date:** [March 30, 2003, 10:33am UTC](https://boards.straightdope.com/t/2-civs-per-galaxy/164997/24 "2003-03-30T10:33:35Z")

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If you made it big enough, it would be at the same temperature as the backgroundradiation- but that would be several light minutes across,  
iirc.  
Anyway, that is one thing the SETI people should be looking for, as well as some kind of powerful anti-asteroid radar which would surely be invaluable for any spacebased society.  
Transmissions of data would almost certainly be tight beam laser in visible light or uv (gamma and x-ray lasers seem to have insurmountable problems for data transmission)…  
the deep space surveys of extragalactic supernovae could perhaps find some of these bursts of light, although they might not recognise them at first.

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**Author:** ![substatique](https://avatars.discourse-cdn.com/v4/letter/s/f19dbf/32.png) [@substatique](https://boards.straightdope.com/u/substatique)\
**Post date:** [March 30, 2003, 11:47am UTC](https://boards.straightdope.com/t/2-civs-per-galaxy/164997/25 "2003-03-30T11:47:15Z")

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OK, um, um, OK, what we’re thinking of as…as aliens, they’re extradimensional beings, that an earlier precursor of the, um, space program made contact with. They are not what they claim to be.

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