Spacecraft Heat Sink
abc123you...@yahoo.com
Well if energy can be turned into mass and as much energy is turned
into mass as possible could it then be used as a heat sink for a
spacecraft?
Brian Davis
> Well if energy can be turned into mass and as much energy
> is turned into mass as possible could it then be used as a
> heat sink for a spacecraft?
Think entropy. The problem with dumping waste heat isn't moving around
energy..
--
Brian Davis
Greg Goss
There's more than one law of thermodynamics. To convert low-quality
energy into high-quality energy is a violation of entropy.
--
apart from one noisy guy up in Canada, no-one wants
a three-cylinder tissue box on bicycle tires.
SolomonW
The laws of entropy would not rule it out as long as some of the energy is
lost.
I could imagine part of the heat sink being hot and radiating energy. An
advanced civilization could turn some of this energy to mass. This mass
could be collected. So following the initial proposal. Why would someone do
it is another question?
Erik Max Francis
> On Sat, 24 Oct 2009 14:41:34 -0700 (PDT), Brian Davis wrote:
>
>> On Oct 24, 5:20 pm, abc123youandmeb...@yahoo.com wrote:
>>
>>> Well if energy can be turned into mass and as much energy
>>> is turned into mass as possible could it then be used as a
>>> heat sink for a spacecraft?
>> Think entropy. The problem with dumping waste heat isn't moving around
>> energy..
>
> The laws of entropy would not rule it out as long as some of the energy is
> lost.
Entropy is not the same thing as energy.
> I could imagine part of the heat sink being hot and radiating energy. An
> advanced civilization could turn some of this energy to mass. This mass
> could be collected. So following the initial proposal. Why would someone do
> it is another question?
Converting energy into mass is turning disorder into order. That's a
decrease in entropy, and macroscopically _that's_ a violation of the
second law of thermodynamics (the thing you were trying to recall
before). Bigtime.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Diplomacy and defense are not substitutes for one another. Either
alone would fail. -- John F. Kennedy, 1917-1963
SolomonW
> SolomonW wrote:
>> On Sat, 24 Oct 2009 14:41:34 -0700 (PDT), Brian Davis wrote:
>>
>>> On Oct 24, 5:20 pm, abc123youandmeb...@yahoo.com wrote:
>>>
>>>> Well if energy can be turned into mass and as much energy
>>>> is turned into mass as possible could it then be used as a
>>>> heat sink for a spacecraft?
>>> Think entropy. The problem with dumping waste heat isn't moving around
>>> energy..
>>
>> The laws of entropy would not rule it out as long as some of the energy is
>> lost.
>
> Entropy is not the same thing as energy.
>
Agreed
>> I could imagine part of the heat sink being hot and radiating energy. An
>> advanced civilization could turn some of this energy to mass. This mass
>> could be collected. So following the initial proposal. Why would someone do
>> it is another question?
>
> Converting energy into mass is turning disorder into order. That's a
> decrease in entropy, and macroscopically _that's_ a violation of the
> second law of thermodynamics (the thing you were trying to recall
> before). Bigtime.
As long as energy escapes so increasing entropy this is not a problem.
Brian Davis
> As long as energy escapes so increasing entropy this is not a problem.
Look at the original post. If you want to use this method as a heat
sink for a closed system (which a spacecraft is, in this sense), then
you could... but only if you had access to a *bigger* heat sink to
pull off the process in the first place.
Kind of like using an oil-fired power plant to generate electricity,
which you then use to run your manufacturing center for liquid
hydrocarbons*. Possible? Certainly. Completely missing the fundamental
point? Uh,huh...
--
Brian Davis
*I think this is also what is known as a "hydrogen based economy" in
some circles. But I digress :).
alie...@gmail.com
> If E=MCsquared then mass is just a form on energy, right?
Right.
> Well if energy can be turned into mass
We don't know how to do this, or even if it's possible.
> and as much energy is turned into mass as possible
As I said, we don't know how to do this, but if it's possible the
Second Law of Thermodynamics will apply, meaning the process itself
will generate waste heat.
Hence even if _all_ the heat energy generated in your ship's power
systems, life support, and so on were converted to mass (presumably
for onboard storage) you'd still have an unavoidable minimum amount of
heat left over that couldn't be converted.
> could it then be used as a heat sink for a spacecraft?
No.
Mark L. Fergerson
SolomonW
> On Oct 25, 4:22�am, SolomonW <Solom...@nospamMail.com> wrote:
>
>> As long as energy escapes so increasing entropy this is not a problem.
>
> Look at the original post. If you want to use this method as a heat
> sink for a closed system (which a spacecraft is, in this sense), then
> you could... but only if you had access to a *bigger* heat sink to
> pull off the process in the first place.
>
Except please read the original post again. It states
"as much energy is turned into mass as possible"
Clearly it is not a closed system.
> Kind of like using an oil-fired power plant to generate electricity,
> which you then use to run your manufacturing center for liquid
> hydrocarbons*. Possible? Certainly. Completely missing the fundamental
> point? Uh,huh...
I agree and actually said "Why would someone do it is another question?"
Tim Little
A heat sink absorbs both energy and entropy. Converting energy to
mass would allow energy to be stored quite compactly, but is likely to
make things much worse regarding entropy. The entropy of matter is
generally microscopic compared with that of equivalent amounts of
energy in other forms, so such a heat "sink" actually requires removal
of almost all the entropy - exactly the opposite of the desired
behaviour.
- Tim