Dyson Sphere and 100D Jump Limit
- Thread starter DaveChase
- Start date
mike wightman
SOC-14 10K
Since you are being a physicist Aramis just a pet peeve of mine.
The unit you are using for heat is wrong - there is no such thing as a 'degree kelvin' the unit should be just 'kelvin' or K for abbreviation.
The unit you are using for heat is wrong - there is no such thing as a 'degree kelvin' the unit should be just 'kelvin' or K for abbreviation.
Funny, but I've seen a dozen texts which disagree with you on that, Mike.
And as Rowlett notes, it's the old proper usage; it was changed by the SI commission in 1967. Lots of texts through the 1980s use °K instead of just K... and most of my physics reading dates to then.
BlackBat242
SOC-14 1K
Grumpy old Physics grognards, holding on to the "Old school ways".
mike wightman
SOC-14 10K
The SI unit for heat is the kelvin K - any reference to degrees kelvin is just plain wrong and sloppy and a throwback to the 60s 
http://physics.nist.gov/cuu/Units/units.html
But since this is Traveller and most of the tech is still firmly stuck in the 60s and 70s sci-fi paradigm perhaps it right to use it
http://physics.nist.gov/cuu/Units/units.html
But since this is Traveller and most of the tech is still firmly stuck in the 60s and 70s sci-fi paradigm perhaps it right to use it
Last edited:
Lategaming
SOC-5
That sentence is just....broken.
We're back in the realm of Handwavium anyway, or at least making our Dyson spheres out of Plotonium.
No, Wil is right. As long as you stay with just the universe, you're up against the laws of Thermodynamics, and we seem to have a pretty good understanding of what can and can't be done. But they only apply to a closed system. If you involve another dimension, it's not a closed system any more.
(Though I would use sub-space instead of jumpspace. You know, the medium that thrusters thrust against?
)Hans
The SI unit for heat is the kelvin K - any reference to degrees kelvin is just plain wrong and sloppy and a throwback to the 60s
Actually, it is a language usage difference. Not a matter of actual science.
Lategaming
SOC-5
I didn't mean any slight but it seems silly to say:
'We'll vent the IR that following the laws of physics has left us with into jumpspace, which is a complete imagination...".
As Jumpspace is one of the "gimmes" of the setting, I suppose it's okay
I didn't mean any slight but it seems silly to say:
'We'll vent the IR that following the laws of physics has left us with into jumpspace, which is a complete imagination...".
As Jumpspace is one of the "gimmes" of the setting, I suppose it's okay
The REAL problem with that statement is, the law of thermodynamics applies to the materials that AREN'T in jump space. So, no help there.
Lategaming
SOC-5
Nope, that's the SI unit of temperature.
mike wightman
SOC-14 10K
Thermodynamic temperature if you want to be that much of a pedant
And it took long enough for someone to point that out.
It's a common trick to catch out 11-12 year olds in physics lessons.
And it took long enough for someone to point that out.
It's a common trick to catch out 11-12 year olds in physics lessons.
Hrrm, instead of jump-space, if portal technology is OTU (TL21 I think?) why not shunt it into lots of different locales, say in orbit around stars in the neighborhood of the Dyson Sphere ...
It may be enough to get the radiation of the Dyson down quite a bit, and give the PC's a bit of a mystery. "Why are there 'stargates' spewing out massive amounts of heat at each of these star systems?"
I figured Grandfather's pocket universe -had- to have some way to shunt heat, and thought it was probably a series of portals pumping the energy directly into the hearts of different stars - which would then, what, age them prematurely perhaps? Maybe another possible Maghiz theory (read the Darrien book - some of those scenarios ... Oh, ICK!!).
It may be enough to get the radiation of the Dyson down quite a bit, and give the PC's a bit of a mystery. "Why are there 'stargates' spewing out massive amounts of heat at each of these star systems?"
I figured Grandfather's pocket universe -had- to have some way to shunt heat, and thought it was probably a series of portals pumping the energy directly into the hearts of different stars - which would then, what, age them prematurely perhaps? Maybe another possible Maghiz theory (read the Darrien book - some of those scenarios ... Oh, ICK!!).
For a pocket universe we can presume a closed system. Grandfather doesn't have a waste heat problem, he has exactly as much energy in his closed system as he WANTS, he just keeps 'recycling' it endlessly using perfectly efficient systems. Heat isn't 'created' energy, obviously, just transferred.
The same 'solution' can exist for a dyson sphere. The 'goal' is to close the system so that all the energy of the existing system can be captured and used for 'work'. Waste Heat may or MAY NOT be a problem depending upon the ability of the builders to use that energy in the efficient ways, and to capture and 'reuse' the waste heat energy. What is inside the Sphere, in fact what that energy is being used for, is just as important question as anything else.
I can postulate that anyone capable of building a Dyson Sphere, and more importantly with a use for that level of energy use, probably is no longer restricted by purely material sciences for their technology. By using powerful gravitic fields the captured energy never touches the shell of the sphere, waste heat from whatever it is they are doing is 'vented' right back into the center of the sphere, sort of like how the alternator on your car recharges the battery used to start said car... the shell of the sphere may be 'warm' in comparison to the rest of space (waste heat from the devices used to funnel the star's energy may be 'dumped' into the mass of the shell to radiate out, a minimal loss, but even that is unnecessary given the level of technology we are talking about.
If you are talking a purely closed system, then we might be speculating that the interior is something like a private reserve: the star is kept stable by the same forces that keep the shell from melting. The system is akin to a museum (or a shelter) for a very high TL race that wanted to remain hidden and thinks (thought?) in the very very long term. If the energy is being used, however, it is probably being 'shunted' somewhere, somehow. Maybe the entire sphere is nothing more than a stellar 'battery' used to 'power' a pocket universe, maybe the entire thing is a planet killing super laser (credomar!), taking all that captured and stored energy to make a ridiculously impractical interstellar beam weapon that can only fire once a millenium, but when it does it can crack a planet light years out (requires one hell of a targeting computer and a lot of patience......).
Okay... I'm done now... second time today my brain ran away with my fingers...
o:
The same 'solution' can exist for a dyson sphere. The 'goal' is to close the system so that all the energy of the existing system can be captured and used for 'work'. Waste Heat may or MAY NOT be a problem depending upon the ability of the builders to use that energy in the efficient ways, and to capture and 'reuse' the waste heat energy. What is inside the Sphere, in fact what that energy is being used for, is just as important question as anything else.
I can postulate that anyone capable of building a Dyson Sphere, and more importantly with a use for that level of energy use, probably is no longer restricted by purely material sciences for their technology. By using powerful gravitic fields the captured energy never touches the shell of the sphere, waste heat from whatever it is they are doing is 'vented' right back into the center of the sphere, sort of like how the alternator on your car recharges the battery used to start said car... the shell of the sphere may be 'warm' in comparison to the rest of space (waste heat from the devices used to funnel the star's energy may be 'dumped' into the mass of the shell to radiate out, a minimal loss, but even that is unnecessary given the level of technology we are talking about.
If you are talking a purely closed system, then we might be speculating that the interior is something like a private reserve: the star is kept stable by the same forces that keep the shell from melting. The system is akin to a museum (or a shelter) for a very high TL race that wanted to remain hidden and thinks (thought?) in the very very long term. If the energy is being used, however, it is probably being 'shunted' somewhere, somehow. Maybe the entire sphere is nothing more than a stellar 'battery' used to 'power' a pocket universe, maybe the entire thing is a planet killing super laser (credomar!), taking all that captured and stored energy to make a ridiculously impractical interstellar beam weapon that can only fire once a millenium, but when it does it can crack a planet light years out (requires one hell of a targeting computer and a lot of patience......).
Okay... I'm done now... second time today my brain ran away with my fingers...
o:Entropy
which, as stated above, results in all input energy eventually becoming infrared emissions.
Couldn't you erect a much smaller Dyson Sphere around a cool Brown Dwarf, around 500K or so? The habitable world would in this case be a tightly orbiting planet. More feasible in terms of material and engineering.
far-trader
SOC-14 10K
Yep. And while fwiw and iirc the required mass was once thought to be 2.some solar systems worth, that was based on Sol as an example and pretty advanced materials and energy sciences. I'm not sure that still holds true with more recent extrasolar discoveries though.
The question becomes, does a smaller star mean more or less minerals in the system?
Also multiple star systems might be more likely to have the required material, having more material in total. Or not.
For a full sphere? it's still got to have unobtanium to work. The gravitational stresses are still an issue, plus the unobtanium needed to be able to make it structurally sound.
Similar threads
