Black holes as heat sinks Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern) The network's official Twitter account is up and running again. What content…Would the Hawking radiation from a small black hole make a feasible propulsion source?How will humanity survive when black holes gain sentience and turn on us?Would the gravitational waves a binary black hole system make a feasible weapon?Protect a planet against a black hole attackDropping a Micro Black Hole into a Gas GiantCould black holes be a better source of energy than stars?Blackholes as Perfect Recyclers or Perfect Batteries: Safe storage, recharge, and usageShort-term Miniature black hole weapon and its effectsAlmost realistic way to beat entropyCould black hole civilizations even exist?
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Black holes as heat sinks
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)
The network's official Twitter account is up and running again. What content…Would the Hawking radiation from a small black hole make a feasible propulsion source?How will humanity survive when black holes gain sentience and turn on us?Would the gravitational waves a binary black hole system make a feasible weapon?Protect a planet against a black hole attackDropping a Micro Black Hole into a Gas GiantCould black holes be a better source of energy than stars?Blackholes as Perfect Recyclers or Perfect Batteries: Safe storage, recharge, and usageShort-term Miniature black hole weapon and its effectsAlmost realistic way to beat entropyCould black hole civilizations even exist?
$begingroup$
Cooling in space is a well known difficulty. There are many unpleasant consequences like no stealth in space, difficult space battles which turn into a short wars of attrition (because you have to either pack your radiators, rendering them useless, or expose them, rendering them vulnerable), and many other complications. This is not only a problem with starships, but also with planets: even Kardashev type I civilization will run into problems keeping their cool if their energy usage on one planet already makes them a type I civilization.
But what if one considers using a black hole as a heat sink?
It seems pretty straightforward to just deposit the waste heat into the black hole, which would have a negligible increase on its mass. However, this seems to be burdened with a bunch of problems which should be addressed:
- Keeping the black hole in place. They are not really objects you can simply grab and hold. But perhaps a charged black hole (Reissner–Nordström or, perhaps even better, Kerr–Newman black hole) could be held using some sort of magnetic confinement.
- Black holes of any reasonable mass and sufficiently small gravitational field in their reasonable proximity have a very small Schwarzschild radius. Therefore, some precise aiming would be required and the question is whether this is possible to do with the waste heat.
- Hawking radiation. Planets depositing their waste heat in black holes probably wouldn't suffer from this problem, but a problem would arise when trying to downsize to for spaceships. Any reasonably small black hole would emit too much Hawking radiation which would make it too hot to be of any use as a heat sink. Using a black hole temperature calculator, it is easy to see that a black hole with a temperature of cozy $300$ K will have a mass of over $4times10^20$ kg, which is almost half the mass of Ceres - plausible for planets, but not so much for spaceships (unless we are talking about something that can be easily confused for a moon). But perhaps using an extremal black hole could help since it should not emit the Hawking radiation.
Can these issues (and perhaps some other relevant key issues, overlooked in the list) be resolved to make a use of a black hole as a heat sink?
If yes, how?
planets spaceships hard-science black-holes thermodynamics
asked 11 hours ago
DanijelDanijel
1,1711022
$endgroup$
This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.
add a comment |
$begingroup$
Cooling in space is a well known difficulty. There are many unpleasant consequences like no stealth in space, difficult space battles which turn into a short wars of attrition (because you have to either pack your radiators, rendering them useless, or expose them, rendering them vulnerable), and many other complications. This is not only a problem with starships, but also with planets: even Kardashev type I civilization will run into problems keeping their cool if their energy usage on one planet already makes them a type I civilization.
But what if one considers using a black hole as a heat sink?
It seems pretty straightforward to just deposit the waste heat into the black hole, which would have a negligible increase on its mass. However, this seems to be burdened with a bunch of problems which should be addressed:
- Keeping the black hole in place. They are not really objects you can simply grab and hold. But perhaps a charged black hole (Reissner–Nordström or, perhaps even better, Kerr–Newman black hole) could be held using some sort of magnetic confinement.
- Black holes of any reasonable mass and sufficiently small gravitational field in their reasonable proximity have a very small Schwarzschild radius. Therefore, some precise aiming would be required and the question is whether this is possible to do with the waste heat.
- Hawking radiation. Planets depositing their waste heat in black holes probably wouldn't suffer from this problem, but a problem would arise when trying to downsize to for spaceships. Any reasonably small black hole would emit too much Hawking radiation which would make it too hot to be of any use as a heat sink. Using a black hole temperature calculator, it is easy to see that a black hole with a temperature of cozy $300$ K will have a mass of over $4times10^20$ kg, which is almost half the mass of Ceres - plausible for planets, but not so much for spaceships (unless we are talking about something that can be easily confused for a moon). But perhaps using an extremal black hole could help since it should not emit the Hawking radiation.
Can these issues (and perhaps some other relevant key issues, overlooked in the list) be resolved to make a use of a black hole as a heat sink?
If yes, how?
planets spaceships hard-science black-holes thermodynamics
asked 11 hours ago
DanijelDanijel
1,1711022
$endgroup$
This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.
$begingroup$
nope, not a chance
$endgroup$
– Kilisi
10 hours ago
3
$begingroup$
Space is effectively already a "black hole" with a temperature of 2.7K (i.e. the CMB) for the purposes of this conversation. That doesn't leave a whole lot of upside even if you ignore all of the practical problems with using a BH.
$endgroup$
– Gene
8 hours ago
2
$begingroup$
You would need a medium to carry the heat in. But if you already had a medium that you could throw away. Youd be fine just jettisoning it into outer space.
$endgroup$
– Dylan
6 hours ago
$begingroup$
I am no physicist, but I'm pretty sure that "some precise aiming" and "waste heat" do not belong in the same paragraph. I suspect that the laws of thermodynamics will somewhat curtail your ability to do that.
$endgroup$
– Solomon Slow
5 hours ago
$begingroup$
@Dylan other than using light as the medium (via radiative cooling, which the OP is explicitly trying to avoid), the only option would be if you could somehow concentrate your waste heat into a smaller mass that you could then jettison. If you did that without generating even more waste heat then you would win every nobel prize for the rest of eternity and be able to generate infinite amounts of energy... en.wikipedia.org/wiki/Maxwell%27s_demon
$endgroup$
– conman
5 hours ago
add a comment |
$begingroup$
Cooling in space is a well known difficulty. There are many unpleasant consequences like no stealth in space, difficult space battles which turn into a short wars of attrition (because you have to either pack your radiators, rendering them useless, or expose them, rendering them vulnerable), and many other complications. This is not only a problem with starships, but also with planets: even Kardashev type I civilization will run into problems keeping their cool if their energy usage on one planet already makes them a type I civilization.
But what if one considers using a black hole as a heat sink?
It seems pretty straightforward to just deposit the waste heat into the black hole, which would have a negligible increase on its mass. However, this seems to be burdened with a bunch of problems which should be addressed:
- Keeping the black hole in place. They are not really objects you can simply grab and hold. But perhaps a charged black hole (Reissner–Nordström or, perhaps even better, Kerr–Newman black hole) could be held using some sort of magnetic confinement.
- Black holes of any reasonable mass and sufficiently small gravitational field in their reasonable proximity have a very small Schwarzschild radius. Therefore, some precise aiming would be required and the question is whether this is possible to do with the waste heat.
- Hawking radiation. Planets depositing their waste heat in black holes probably wouldn't suffer from this problem, but a problem would arise when trying to downsize to for spaceships. Any reasonably small black hole would emit too much Hawking radiation which would make it too hot to be of any use as a heat sink. Using a black hole temperature calculator, it is easy to see that a black hole with a temperature of cozy $300$ K will have a mass of over $4times10^20$ kg, which is almost half the mass of Ceres - plausible for planets, but not so much for spaceships (unless we are talking about something that can be easily confused for a moon). But perhaps using an extremal black hole could help since it should not emit the Hawking radiation.
Can these issues (and perhaps some other relevant key issues, overlooked in the list) be resolved to make a use of a black hole as a heat sink?
If yes, how?
planets spaceships hard-science black-holes thermodynamics
asked 11 hours ago
DanijelDanijel
1,1711022
$endgroup$
Cooling in space is a well known difficulty. There are many unpleasant consequences like no stealth in space, difficult space battles which turn into a short wars of attrition (because you have to either pack your radiators, rendering them useless, or expose them, rendering them vulnerable), and many other complications. This is not only a problem with starships, but also with planets: even Kardashev type I civilization will run into problems keeping their cool if their energy usage on one planet already makes them a type I civilization.
But what if one considers using a black hole as a heat sink?
It seems pretty straightforward to just deposit the waste heat into the black hole, which would have a negligible increase on its mass. However, this seems to be burdened with a bunch of problems which should be addressed:
- Keeping the black hole in place. They are not really objects you can simply grab and hold. But perhaps a charged black hole (Reissner–Nordström or, perhaps even better, Kerr–Newman black hole) could be held using some sort of magnetic confinement.
- Black holes of any reasonable mass and sufficiently small gravitational field in their reasonable proximity have a very small Schwarzschild radius. Therefore, some precise aiming would be required and the question is whether this is possible to do with the waste heat.
- Hawking radiation. Planets depositing their waste heat in black holes probably wouldn't suffer from this problem, but a problem would arise when trying to downsize to for spaceships. Any reasonably small black hole would emit too much Hawking radiation which would make it too hot to be of any use as a heat sink. Using a black hole temperature calculator, it is easy to see that a black hole with a temperature of cozy $300$ K will have a mass of over $4times10^20$ kg, which is almost half the mass of Ceres - plausible for planets, but not so much for spaceships (unless we are talking about something that can be easily confused for a moon). But perhaps using an extremal black hole could help since it should not emit the Hawking radiation.
Can these issues (and perhaps some other relevant key issues, overlooked in the list) be resolved to make a use of a black hole as a heat sink?
If yes, how?
planets spaceships hard-science black-holes thermodynamics
planets spaceships hard-science black-holes thermodynamics
asked 11 hours ago
DanijelDanijel
1,1711022
asked 11 hours ago
DanijelDanijel
1,1711022
asked 11 hours ago
DanijelDanijel
1,1711022
asked 11 hours ago
DanijelDanijel
1,1711022
asked 11 hours ago
DanijelDanijel
1,1711022
1,1711022
This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.
This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.
$begingroup$
nope, not a chance
$endgroup$
– Kilisi
10 hours ago
3
$begingroup$
Space is effectively already a "black hole" with a temperature of 2.7K (i.e. the CMB) for the purposes of this conversation. That doesn't leave a whole lot of upside even if you ignore all of the practical problems with using a BH.
$endgroup$
– Gene
8 hours ago
2
$begingroup$
You would need a medium to carry the heat in. But if you already had a medium that you could throw away. Youd be fine just jettisoning it into outer space.
$endgroup$
– Dylan
6 hours ago
$begingroup$
I am no physicist, but I'm pretty sure that "some precise aiming" and "waste heat" do not belong in the same paragraph. I suspect that the laws of thermodynamics will somewhat curtail your ability to do that.
$endgroup$
– Solomon Slow
5 hours ago
$begingroup$
@Dylan other than using light as the medium (via radiative cooling, which the OP is explicitly trying to avoid), the only option would be if you could somehow concentrate your waste heat into a smaller mass that you could then jettison. If you did that without generating even more waste heat then you would win every nobel prize for the rest of eternity and be able to generate infinite amounts of energy... en.wikipedia.org/wiki/Maxwell%27s_demon
$endgroup$
– conman
5 hours ago
add a comment |
$begingroup$
nope, not a chance
$endgroup$
– Kilisi
10 hours ago
3
$begingroup$
Space is effectively already a "black hole" with a temperature of 2.7K (i.e. the CMB) for the purposes of this conversation. That doesn't leave a whole lot of upside even if you ignore all of the practical problems with using a BH.
$endgroup$
– Gene
8 hours ago
2
$begingroup$
You would need a medium to carry the heat in. But if you already had a medium that you could throw away. Youd be fine just jettisoning it into outer space.
$endgroup$
– Dylan
6 hours ago
$begingroup$
I am no physicist, but I'm pretty sure that "some precise aiming" and "waste heat" do not belong in the same paragraph. I suspect that the laws of thermodynamics will somewhat curtail your ability to do that.
$endgroup$
– Solomon Slow
5 hours ago
$begingroup$
@Dylan other than using light as the medium (via radiative cooling, which the OP is explicitly trying to avoid), the only option would be if you could somehow concentrate your waste heat into a smaller mass that you could then jettison. If you did that without generating even more waste heat then you would win every nobel prize for the rest of eternity and be able to generate infinite amounts of energy... en.wikipedia.org/wiki/Maxwell%27s_demon
$endgroup$
– conman
5 hours ago
$begingroup$
nope, not a chance
$endgroup$
– Kilisi
10 hours ago
$begingroup$
nope, not a chance
$endgroup$
– Kilisi
10 hours ago
3
3
$begingroup$
Space is effectively already a "black hole" with a temperature of 2.7K (i.e. the CMB) for the purposes of this conversation. That doesn't leave a whole lot of upside even if you ignore all of the practical problems with using a BH.
$endgroup$
– Gene
8 hours ago
$begingroup$
Space is effectively already a "black hole" with a temperature of 2.7K (i.e. the CMB) for the purposes of this conversation. That doesn't leave a whole lot of upside even if you ignore all of the practical problems with using a BH.
$endgroup$
– Gene
8 hours ago
2
2
$begingroup$
You would need a medium to carry the heat in. But if you already had a medium that you could throw away. Youd be fine just jettisoning it into outer space.
$endgroup$
– Dylan
6 hours ago
$begingroup$
You would need a medium to carry the heat in. But if you already had a medium that you could throw away. Youd be fine just jettisoning it into outer space.
$endgroup$
– Dylan
6 hours ago
$begingroup$
I am no physicist, but I'm pretty sure that "some precise aiming" and "waste heat" do not belong in the same paragraph. I suspect that the laws of thermodynamics will somewhat curtail your ability to do that.
$endgroup$
– Solomon Slow
5 hours ago
$begingroup$
I am no physicist, but I'm pretty sure that "some precise aiming" and "waste heat" do not belong in the same paragraph. I suspect that the laws of thermodynamics will somewhat curtail your ability to do that.
$endgroup$
– Solomon Slow
5 hours ago
$begingroup$
@Dylan other than using light as the medium (via radiative cooling, which the OP is explicitly trying to avoid), the only option would be if you could somehow concentrate your waste heat into a smaller mass that you could then jettison. If you did that without generating even more waste heat then you would win every nobel prize for the rest of eternity and be able to generate infinite amounts of energy... en.wikipedia.org/wiki/Maxwell%27s_demon
$endgroup$
– conman
5 hours ago
$begingroup$
@Dylan other than using light as the medium (via radiative cooling, which the OP is explicitly trying to avoid), the only option would be if you could somehow concentrate your waste heat into a smaller mass that you could then jettison. If you did that without generating even more waste heat then you would win every nobel prize for the rest of eternity and be able to generate infinite amounts of energy... en.wikipedia.org/wiki/Maxwell%27s_demon
$endgroup$
– conman
5 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Your issue is right here
It seems pretty straightforward to just deposit the waste heat into
the black hole
Unfortunately this isn't true. The problem is that heat isn't something you can just dump into a black hole. To be clear, heat is just the random motions of atoms and molecules inside substances. There isn't a way to just "move" that into something else, regardless of your black hole's ability to absorb things. For reference, if you could somehow "move" the heat around without generating more waste heat in the process, you would have invented a lossless Maxwell's Demon, violated the second law of thermodynamics, invented an infinite energy source, and won every single Nobel Prize in physics for the rest of history, all in one go.
There is only one way you could dump heat into a black hole, which is by converting it into light and sending the light into your black hole. It turns out there is a way to convert waste heat into light. It is called thermal radiation and all materials do it naturally and automatically as a result of being hot. Taking something which is hot and cooling it by allowing it to radiate its heat as light energy is of course the well known process of radiative cooling. The trouble is that when you try to use radiative cooling to cool something, the question of where the light goes is never the problem. The bigger issue is efficiency. Radiative cooling is very inefficient, so you end up creating large "fins" to increase the surface area to generate as much cooling power as possible. For example, the radiators for the active heat exchange system on the ISS are not as large as the solar panels, but are still one of the larger features on the ISS.
This all means that the limiting factor with radiative cooling isn't where you send the light - in fact, you typically don't even care about that. Sending it off into empty space is as great as any other option. The limit is your total surface area available for cooling. Putting a black hole in the mix doesn't change any of that, so it brings no benefit to your cooling system at all. In short, we're right back to the problem you are trying to solve in the first place - the only way to dump heat into black holes is by radiative cooling, and that is what you were trying to avoid in the first place. In summary:
- There is no way to directly transfer "heat" to a black hole.
- The only way to get heat into a black hole would be by converting waste energy into light and sending that into the black hole
- However, the main problem that makes cooling so hard in the first place are the inefficiencies involved in converting waste energy into light
- If you came up with a way to efficiently convert waste energy into light you wouldn't need a black hole anyway - it would be sufficient to just send it into space.
- Therefore, a black hole cannot help with cooling at all
answered 10 hours ago
conmanconman
1,044419
$endgroup$
1
$begingroup$
If you came up with a way to efficiently convert waste energy into heat..., you mean light; most of the time waste energy is heat. Also, if you did find a way to convert it to light, you'd reabsorb it with your solar panels and use it again
$endgroup$
– nzaman
9 hours ago
1
$begingroup$
You can do it if your black hole can be converted into a "sheet" and use it to surround your ship. You are still outside the event horizon, but the BH will absorb your thermal radiation in the ultimate "Nigth-Sky Cooling"
$endgroup$
– SilverCookies
9 hours ago
2
$begingroup$
@SilverCookies Sure, except that such an arrangement would violate everything we know about physics. At that point in time there are easier ways to handwave things away. Even then though, this doesn't help your ship cool faster, as you are still limited to the rate at which you can radiatively cool your ship. All it does is hide your heat signature.
$endgroup$
– conman
9 hours ago
1
$begingroup$
@DavidTonhofer although again, even if you could somehow make and expel hot matter to lose heat, you still don't need a blackhole - just shoot it off into space and let it drift forever, slowly cooling. Which is kind of my whole point. You can't physically attach yourself to a black hole, so any method by which you could send "heat" energy into a black hole would work just as well by sending that same energy into space. A black hole has no practical benefit.
$endgroup$
– conman
3 hours ago
1
$begingroup$
The black hole would allow you to get slightly cooler than the background radiation allows, but only if the black hole is truly massive and you build a dyson-sphere-esque structure around it. Insulate the outside and have your radiative panels on the inside. That's a lot of work for slightly more cooling, though.
$endgroup$
– Harabeck
2 hours ago
|
show 9 more comments
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1 Answer
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active
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votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Your issue is right here
It seems pretty straightforward to just deposit the waste heat into
the black hole
Unfortunately this isn't true. The problem is that heat isn't something you can just dump into a black hole. To be clear, heat is just the random motions of atoms and molecules inside substances. There isn't a way to just "move" that into something else, regardless of your black hole's ability to absorb things. For reference, if you could somehow "move" the heat around without generating more waste heat in the process, you would have invented a lossless Maxwell's Demon, violated the second law of thermodynamics, invented an infinite energy source, and won every single Nobel Prize in physics for the rest of history, all in one go.
There is only one way you could dump heat into a black hole, which is by converting it into light and sending the light into your black hole. It turns out there is a way to convert waste heat into light. It is called thermal radiation and all materials do it naturally and automatically as a result of being hot. Taking something which is hot and cooling it by allowing it to radiate its heat as light energy is of course the well known process of radiative cooling. The trouble is that when you try to use radiative cooling to cool something, the question of where the light goes is never the problem. The bigger issue is efficiency. Radiative cooling is very inefficient, so you end up creating large "fins" to increase the surface area to generate as much cooling power as possible. For example, the radiators for the active heat exchange system on the ISS are not as large as the solar panels, but are still one of the larger features on the ISS.
This all means that the limiting factor with radiative cooling isn't where you send the light - in fact, you typically don't even care about that. Sending it off into empty space is as great as any other option. The limit is your total surface area available for cooling. Putting a black hole in the mix doesn't change any of that, so it brings no benefit to your cooling system at all. In short, we're right back to the problem you are trying to solve in the first place - the only way to dump heat into black holes is by radiative cooling, and that is what you were trying to avoid in the first place. In summary:
- There is no way to directly transfer "heat" to a black hole.
- The only way to get heat into a black hole would be by converting waste energy into light and sending that into the black hole
- However, the main problem that makes cooling so hard in the first place are the inefficiencies involved in converting waste energy into light
- If you came up with a way to efficiently convert waste energy into light you wouldn't need a black hole anyway - it would be sufficient to just send it into space.
- Therefore, a black hole cannot help with cooling at all
answered 10 hours ago
conmanconman
1,044419
$endgroup$
1
$begingroup$
If you came up with a way to efficiently convert waste energy into heat..., you mean light; most of the time waste energy is heat. Also, if you did find a way to convert it to light, you'd reabsorb it with your solar panels and use it again
$endgroup$
– nzaman
9 hours ago
1
$begingroup$
You can do it if your black hole can be converted into a "sheet" and use it to surround your ship. You are still outside the event horizon, but the BH will absorb your thermal radiation in the ultimate "Nigth-Sky Cooling"
$endgroup$
– SilverCookies
9 hours ago
2
$begingroup$
@SilverCookies Sure, except that such an arrangement would violate everything we know about physics. At that point in time there are easier ways to handwave things away. Even then though, this doesn't help your ship cool faster, as you are still limited to the rate at which you can radiatively cool your ship. All it does is hide your heat signature.
$endgroup$
– conman
9 hours ago
1
$begingroup$
@DavidTonhofer although again, even if you could somehow make and expel hot matter to lose heat, you still don't need a blackhole - just shoot it off into space and let it drift forever, slowly cooling. Which is kind of my whole point. You can't physically attach yourself to a black hole, so any method by which you could send "heat" energy into a black hole would work just as well by sending that same energy into space. A black hole has no practical benefit.
$endgroup$
– conman
3 hours ago
1
$begingroup$
The black hole would allow you to get slightly cooler than the background radiation allows, but only if the black hole is truly massive and you build a dyson-sphere-esque structure around it. Insulate the outside and have your radiative panels on the inside. That's a lot of work for slightly more cooling, though.
$endgroup$
– Harabeck
2 hours ago
|
show 9 more comments
$begingroup$
Your issue is right here
It seems pretty straightforward to just deposit the waste heat into
the black hole
Unfortunately this isn't true. The problem is that heat isn't something you can just dump into a black hole. To be clear, heat is just the random motions of atoms and molecules inside substances. There isn't a way to just "move" that into something else, regardless of your black hole's ability to absorb things. For reference, if you could somehow "move" the heat around without generating more waste heat in the process, you would have invented a lossless Maxwell's Demon, violated the second law of thermodynamics, invented an infinite energy source, and won every single Nobel Prize in physics for the rest of history, all in one go.
There is only one way you could dump heat into a black hole, which is by converting it into light and sending the light into your black hole. It turns out there is a way to convert waste heat into light. It is called thermal radiation and all materials do it naturally and automatically as a result of being hot. Taking something which is hot and cooling it by allowing it to radiate its heat as light energy is of course the well known process of radiative cooling. The trouble is that when you try to use radiative cooling to cool something, the question of where the light goes is never the problem. The bigger issue is efficiency. Radiative cooling is very inefficient, so you end up creating large "fins" to increase the surface area to generate as much cooling power as possible. For example, the radiators for the active heat exchange system on the ISS are not as large as the solar panels, but are still one of the larger features on the ISS.
This all means that the limiting factor with radiative cooling isn't where you send the light - in fact, you typically don't even care about that. Sending it off into empty space is as great as any other option. The limit is your total surface area available for cooling. Putting a black hole in the mix doesn't change any of that, so it brings no benefit to your cooling system at all. In short, we're right back to the problem you are trying to solve in the first place - the only way to dump heat into black holes is by radiative cooling, and that is what you were trying to avoid in the first place. In summary:
- There is no way to directly transfer "heat" to a black hole.
- The only way to get heat into a black hole would be by converting waste energy into light and sending that into the black hole
- However, the main problem that makes cooling so hard in the first place are the inefficiencies involved in converting waste energy into light
- If you came up with a way to efficiently convert waste energy into light you wouldn't need a black hole anyway - it would be sufficient to just send it into space.
- Therefore, a black hole cannot help with cooling at all
answered 10 hours ago
conmanconman
1,044419
$endgroup$
1
$begingroup$
If you came up with a way to efficiently convert waste energy into heat..., you mean light; most of the time waste energy is heat. Also, if you did find a way to convert it to light, you'd reabsorb it with your solar panels and use it again
$endgroup$
– nzaman
9 hours ago
1
$begingroup$
You can do it if your black hole can be converted into a "sheet" and use it to surround your ship. You are still outside the event horizon, but the BH will absorb your thermal radiation in the ultimate "Nigth-Sky Cooling"
$endgroup$
– SilverCookies
9 hours ago
2
$begingroup$
@SilverCookies Sure, except that such an arrangement would violate everything we know about physics. At that point in time there are easier ways to handwave things away. Even then though, this doesn't help your ship cool faster, as you are still limited to the rate at which you can radiatively cool your ship. All it does is hide your heat signature.
$endgroup$
– conman
9 hours ago
1
$begingroup$
@DavidTonhofer although again, even if you could somehow make and expel hot matter to lose heat, you still don't need a blackhole - just shoot it off into space and let it drift forever, slowly cooling. Which is kind of my whole point. You can't physically attach yourself to a black hole, so any method by which you could send "heat" energy into a black hole would work just as well by sending that same energy into space. A black hole has no practical benefit.
$endgroup$
– conman
3 hours ago
1
$begingroup$
The black hole would allow you to get slightly cooler than the background radiation allows, but only if the black hole is truly massive and you build a dyson-sphere-esque structure around it. Insulate the outside and have your radiative panels on the inside. That's a lot of work for slightly more cooling, though.
$endgroup$
– Harabeck
2 hours ago
|
show 9 more comments
$begingroup$
Your issue is right here
It seems pretty straightforward to just deposit the waste heat into
the black hole
Unfortunately this isn't true. The problem is that heat isn't something you can just dump into a black hole. To be clear, heat is just the random motions of atoms and molecules inside substances. There isn't a way to just "move" that into something else, regardless of your black hole's ability to absorb things. For reference, if you could somehow "move" the heat around without generating more waste heat in the process, you would have invented a lossless Maxwell's Demon, violated the second law of thermodynamics, invented an infinite energy source, and won every single Nobel Prize in physics for the rest of history, all in one go.
There is only one way you could dump heat into a black hole, which is by converting it into light and sending the light into your black hole. It turns out there is a way to convert waste heat into light. It is called thermal radiation and all materials do it naturally and automatically as a result of being hot. Taking something which is hot and cooling it by allowing it to radiate its heat as light energy is of course the well known process of radiative cooling. The trouble is that when you try to use radiative cooling to cool something, the question of where the light goes is never the problem. The bigger issue is efficiency. Radiative cooling is very inefficient, so you end up creating large "fins" to increase the surface area to generate as much cooling power as possible. For example, the radiators for the active heat exchange system on the ISS are not as large as the solar panels, but are still one of the larger features on the ISS.
This all means that the limiting factor with radiative cooling isn't where you send the light - in fact, you typically don't even care about that. Sending it off into empty space is as great as any other option. The limit is your total surface area available for cooling. Putting a black hole in the mix doesn't change any of that, so it brings no benefit to your cooling system at all. In short, we're right back to the problem you are trying to solve in the first place - the only way to dump heat into black holes is by radiative cooling, and that is what you were trying to avoid in the first place. In summary:
- There is no way to directly transfer "heat" to a black hole.
- The only way to get heat into a black hole would be by converting waste energy into light and sending that into the black hole
- However, the main problem that makes cooling so hard in the first place are the inefficiencies involved in converting waste energy into light
- If you came up with a way to efficiently convert waste energy into light you wouldn't need a black hole anyway - it would be sufficient to just send it into space.
- Therefore, a black hole cannot help with cooling at all
answered 10 hours ago
conmanconman
1,044419
$endgroup$
Your issue is right here
It seems pretty straightforward to just deposit the waste heat into
the black hole
Unfortunately this isn't true. The problem is that heat isn't something you can just dump into a black hole. To be clear, heat is just the random motions of atoms and molecules inside substances. There isn't a way to just "move" that into something else, regardless of your black hole's ability to absorb things. For reference, if you could somehow "move" the heat around without generating more waste heat in the process, you would have invented a lossless Maxwell's Demon, violated the second law of thermodynamics, invented an infinite energy source, and won every single Nobel Prize in physics for the rest of history, all in one go.
There is only one way you could dump heat into a black hole, which is by converting it into light and sending the light into your black hole. It turns out there is a way to convert waste heat into light. It is called thermal radiation and all materials do it naturally and automatically as a result of being hot. Taking something which is hot and cooling it by allowing it to radiate its heat as light energy is of course the well known process of radiative cooling. The trouble is that when you try to use radiative cooling to cool something, the question of where the light goes is never the problem. The bigger issue is efficiency. Radiative cooling is very inefficient, so you end up creating large "fins" to increase the surface area to generate as much cooling power as possible. For example, the radiators for the active heat exchange system on the ISS are not as large as the solar panels, but are still one of the larger features on the ISS.
This all means that the limiting factor with radiative cooling isn't where you send the light - in fact, you typically don't even care about that. Sending it off into empty space is as great as any other option. The limit is your total surface area available for cooling. Putting a black hole in the mix doesn't change any of that, so it brings no benefit to your cooling system at all. In short, we're right back to the problem you are trying to solve in the first place - the only way to dump heat into black holes is by radiative cooling, and that is what you were trying to avoid in the first place. In summary:
- There is no way to directly transfer "heat" to a black hole.
- The only way to get heat into a black hole would be by converting waste energy into light and sending that into the black hole
- However, the main problem that makes cooling so hard in the first place are the inefficiencies involved in converting waste energy into light
- If you came up with a way to efficiently convert waste energy into light you wouldn't need a black hole anyway - it would be sufficient to just send it into space.
- Therefore, a black hole cannot help with cooling at all
answered 10 hours ago
conmanconman
1,044419
edited 5 hours ago
answered 10 hours ago
conmanconman
1,044419
answered 10 hours ago
conmanconman
1,044419
answered 10 hours ago
conmanconman
1,044419
1,044419
1
$begingroup$
If you came up with a way to efficiently convert waste energy into heat..., you mean light; most of the time waste energy is heat. Also, if you did find a way to convert it to light, you'd reabsorb it with your solar panels and use it again
$endgroup$
– nzaman
9 hours ago
1
$begingroup$
You can do it if your black hole can be converted into a "sheet" and use it to surround your ship. You are still outside the event horizon, but the BH will absorb your thermal radiation in the ultimate "Nigth-Sky Cooling"
$endgroup$
– SilverCookies
9 hours ago
2
$begingroup$
@SilverCookies Sure, except that such an arrangement would violate everything we know about physics. At that point in time there are easier ways to handwave things away. Even then though, this doesn't help your ship cool faster, as you are still limited to the rate at which you can radiatively cool your ship. All it does is hide your heat signature.
$endgroup$
– conman
9 hours ago
1
$begingroup$
@DavidTonhofer although again, even if you could somehow make and expel hot matter to lose heat, you still don't need a blackhole - just shoot it off into space and let it drift forever, slowly cooling. Which is kind of my whole point. You can't physically attach yourself to a black hole, so any method by which you could send "heat" energy into a black hole would work just as well by sending that same energy into space. A black hole has no practical benefit.
$endgroup$
– conman
3 hours ago
1
$begingroup$
The black hole would allow you to get slightly cooler than the background radiation allows, but only if the black hole is truly massive and you build a dyson-sphere-esque structure around it. Insulate the outside and have your radiative panels on the inside. That's a lot of work for slightly more cooling, though.
$endgroup$
– Harabeck
2 hours ago
|
show 9 more comments
1
$begingroup$
If you came up with a way to efficiently convert waste energy into heat..., you mean light; most of the time waste energy is heat. Also, if you did find a way to convert it to light, you'd reabsorb it with your solar panels and use it again
$endgroup$
– nzaman
9 hours ago
1
$begingroup$
You can do it if your black hole can be converted into a "sheet" and use it to surround your ship. You are still outside the event horizon, but the BH will absorb your thermal radiation in the ultimate "Nigth-Sky Cooling"
$endgroup$
– SilverCookies
9 hours ago
2
$begingroup$
@SilverCookies Sure, except that such an arrangement would violate everything we know about physics. At that point in time there are easier ways to handwave things away. Even then though, this doesn't help your ship cool faster, as you are still limited to the rate at which you can radiatively cool your ship. All it does is hide your heat signature.
$endgroup$
– conman
9 hours ago
1
$begingroup$
@DavidTonhofer although again, even if you could somehow make and expel hot matter to lose heat, you still don't need a blackhole - just shoot it off into space and let it drift forever, slowly cooling. Which is kind of my whole point. You can't physically attach yourself to a black hole, so any method by which you could send "heat" energy into a black hole would work just as well by sending that same energy into space. A black hole has no practical benefit.
$endgroup$
– conman
3 hours ago
1
$begingroup$
The black hole would allow you to get slightly cooler than the background radiation allows, but only if the black hole is truly massive and you build a dyson-sphere-esque structure around it. Insulate the outside and have your radiative panels on the inside. That's a lot of work for slightly more cooling, though.
$endgroup$
– Harabeck
2 hours ago
1
1
$begingroup$
If you came up with a way to efficiently convert waste energy into heat..., you mean light; most of the time waste energy is heat. Also, if you did find a way to convert it to light, you'd reabsorb it with your solar panels and use it again$endgroup$
– nzaman
9 hours ago
$begingroup$
If you came up with a way to efficiently convert waste energy into heat..., you mean light; most of the time waste energy is heat. Also, if you did find a way to convert it to light, you'd reabsorb it with your solar panels and use it again$endgroup$
– nzaman
9 hours ago
1
1
$begingroup$
You can do it if your black hole can be converted into a "sheet" and use it to surround your ship. You are still outside the event horizon, but the BH will absorb your thermal radiation in the ultimate "Nigth-Sky Cooling"
$endgroup$
– SilverCookies
9 hours ago
$begingroup$
You can do it if your black hole can be converted into a "sheet" and use it to surround your ship. You are still outside the event horizon, but the BH will absorb your thermal radiation in the ultimate "Nigth-Sky Cooling"
$endgroup$
– SilverCookies
9 hours ago
2
2
$begingroup$
@SilverCookies Sure, except that such an arrangement would violate everything we know about physics. At that point in time there are easier ways to handwave things away. Even then though, this doesn't help your ship cool faster, as you are still limited to the rate at which you can radiatively cool your ship. All it does is hide your heat signature.
$endgroup$
– conman
9 hours ago
$begingroup$
@SilverCookies Sure, except that such an arrangement would violate everything we know about physics. At that point in time there are easier ways to handwave things away. Even then though, this doesn't help your ship cool faster, as you are still limited to the rate at which you can radiatively cool your ship. All it does is hide your heat signature.
$endgroup$
– conman
9 hours ago
1
1
$begingroup$
@DavidTonhofer although again, even if you could somehow make and expel hot matter to lose heat, you still don't need a blackhole - just shoot it off into space and let it drift forever, slowly cooling. Which is kind of my whole point. You can't physically attach yourself to a black hole, so any method by which you could send "heat" energy into a black hole would work just as well by sending that same energy into space. A black hole has no practical benefit.
$endgroup$
– conman
3 hours ago
$begingroup$
@DavidTonhofer although again, even if you could somehow make and expel hot matter to lose heat, you still don't need a blackhole - just shoot it off into space and let it drift forever, slowly cooling. Which is kind of my whole point. You can't physically attach yourself to a black hole, so any method by which you could send "heat" energy into a black hole would work just as well by sending that same energy into space. A black hole has no practical benefit.
$endgroup$
– conman
3 hours ago
1
1
$begingroup$
The black hole would allow you to get slightly cooler than the background radiation allows, but only if the black hole is truly massive and you build a dyson-sphere-esque structure around it. Insulate the outside and have your radiative panels on the inside. That's a lot of work for slightly more cooling, though.
$endgroup$
– Harabeck
2 hours ago
$begingroup$
The black hole would allow you to get slightly cooler than the background radiation allows, but only if the black hole is truly massive and you build a dyson-sphere-esque structure around it. Insulate the outside and have your radiative panels on the inside. That's a lot of work for slightly more cooling, though.
$endgroup$
– Harabeck
2 hours ago
|
show 9 more comments
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$begingroup$
nope, not a chance
$endgroup$
– Kilisi
10 hours ago
3
$begingroup$
Space is effectively already a "black hole" with a temperature of 2.7K (i.e. the CMB) for the purposes of this conversation. That doesn't leave a whole lot of upside even if you ignore all of the practical problems with using a BH.
$endgroup$
– Gene
8 hours ago
2
$begingroup$
You would need a medium to carry the heat in. But if you already had a medium that you could throw away. Youd be fine just jettisoning it into outer space.
$endgroup$
– Dylan
6 hours ago
$begingroup$
I am no physicist, but I'm pretty sure that "some precise aiming" and "waste heat" do not belong in the same paragraph. I suspect that the laws of thermodynamics will somewhat curtail your ability to do that.
$endgroup$
– Solomon Slow
5 hours ago
$begingroup$
@Dylan other than using light as the medium (via radiative cooling, which the OP is explicitly trying to avoid), the only option would be if you could somehow concentrate your waste heat into a smaller mass that you could then jettison. If you did that without generating even more waste heat then you would win every nobel prize for the rest of eternity and be able to generate infinite amounts of energy... en.wikipedia.org/wiki/Maxwell%27s_demon
$endgroup$
– conman
5 hours ago