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It's been established that cloaking devices such as those used by the Romulans or in the USS Defiant require a great amount of energy to sustain.

But wouldn't the energy have to go somewhere or end up violating at least several laws of thermodynamics. Either the temperature within the cloaked area would have to increase or they would have to dump the energy somewhere?

Note 1: Getting rid of heat is a critical problem on many of our current (21st century) spaceships (ie. satellites). Space isn't cold, just well insulated.

Note 2: If the federation used passive cloaking such as the current class of metamaterials that bend EM radition around themselves, that'd be one thing, but they'd still have to deal with the considerable energy created by the warp core running -- and all those human bodies, life support systems, etc.

Valorum
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RoboKaren
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1 Answers1

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The Klingon Bird of Prey Owner's Workshop Manual, which was coauthored by Rick Sternbach (Sternbach and Michael Okuda were the technical consultants on Star Trek: The Next Generation and subsequent shows, and they wrote the Next Generation Technical Manual which is often treated as canonical), describes the Klingon cloak on p. 46:

The cloaking field acts to mask the presence of the Bird-of-Prey through quantum teleportation, by actively transporting matter and energy from outside the envelope to the other side almost entirely unchanged and detectable only with the fastest and most sensitive instruments. Matter and energy produced inside the envelope, from sources like the ship's impulse engines, are temporarily stored within the field. An extremely small fraction of the total energy flux from local space, approximately 0.003 per cent, penetrates the cloak to allow for sub-light navigation.

An EM field produced by the emitter on the ship's exterior performs the actual cloaking by way of a complex spatial phasing of most incoming radiation. This phasing involves the short-range, almost instantaneous, quantum teleportation of radiation and particles through the cloak envelope as well as the ship itself. While the process is not 100 per cent efficient, it works well in the majority of situations a Bird-of-Prey is likely to encounter.

The bolded sentence explains what happens to heat generated from within--it is somehow stored within the field of the cloak itself, which must act as a heat sink while the ship remains cloaked. I would guess the heat can be dumped into space when the ship decloaks.

Hypnosifl
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    Your last sentence is interesting - that means decloaking is not just a quiet sneak around the corner, but a huge bang advertising HERE I AM if the heat is dumped in a rather short timeframe... – Benedikt Jul 15 '14 at 06:04
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    How would the heat dumped into space? Space is mostly vacuum, so the heat dissipation is very small, or so I have read. – Flamma Jul 15 '14 at 09:09
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    @Flamma space is mostly cold vacuum, so heat could be dumped as thermal radiation (also known as radiant heat.) To dump it quickly, the radiation would have to be quite intense. You are right to say that heat cannot be dissipated by convection or conduction in a vacuum. Because thermal radiation crosses a vacuum, the glass of a vacuum flask, and the insulation of a real life spacecraft, are silvered. – Qsigma Jul 15 '14 at 09:29
  • This raises another question though: how do the engines propel the ship if the energy stays inside the field? Basic laws of Newton: the transfer of energy from the engine exhaust hits the field edge meaning it shouldn't affect the momentum of the ship. It's like pushing your car while seated inside it, you push just as hard against your chair as against your dashboard. – Nzall Jul 15 '14 at 09:30
  • @Qsigma Thanks for the explanation. I didn't know vaccum could be cold or hot. – Flamma Jul 15 '14 at 10:36
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    @NateKerkhofs Other than just saying "the ships can move so it must work," we know that the cloak does allow for ionized gas to exit the field, as demonstrated in Star Trek VI. – Xantec Jul 15 '14 at 12:02
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    @Benedikt With sensors that can receive information faster than the speed of light, I don't think the light-speed shock-wave of radiation from the cloak turning off is that big of a deal. – Xantec Jul 15 '14 at 12:11
  • @Xantec But wouldn't the light-speed shockwave also be detected with these faster-than-light-sensors? Independently how these sensors will work, they will still scale somehow with the energy which is deposited and this energy scales with 1/r^2 (r being the distance between you and the source) - so if you deposit a huge amount of energy you will be seen from bigger distances, I assume? – Benedikt Jul 15 '14 at 12:43
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    Does motion caused by warping space require Newtonian physics to (not) apply? – RoboKaren Jul 15 '14 at 12:48
  • @Benedikt It is nearly impossible to say with any surety. Even the question I linked didn't really have any decent answer. – Xantec Jul 15 '14 at 12:48
  • RoboKaren: My argument is more general than Newtonian Physics, it's more or less a geometrical argument about the surface of a sphere, which should also apply to relativity theory (maybe with some minor corrections), but for the argument it's not important wether it scales with 1/r^1.9 or 1/r^2.1 ... Bus as @Xantec has pointed out, this is all speculation - maybe something for a new question? – Benedikt Jul 15 '14 at 12:54
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    @Benedikt - couldn't the thermal radiation be aimed in a particular direction, say be enclosing it in a force field which has a single "hole" that allows it to escape into space? Might not be much greater than the radiation given off by firing impulse engines. – Hypnosifl Jul 15 '14 at 13:40
  • @NateKerkhofs, Obviously, the Flintstones got involved. They're experts at pushing a car from the inside. :P – Brian S Jul 15 '14 at 14:12
  • @BrianS The Flintstones still had their feet on the ground. in this case, there is no direct interface with the ground. – Nzall Jul 15 '14 at 14:17
  • @NateKerkhofs, It's a joke. -_- – Brian S Jul 15 '14 at 14:18
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    @Benedikt Every time someone decloaks, its instant "CAPTAIN! Klingon bird of prey Declocking off the Starboard Bow!" "RED ALERT". It's always alarming, but the entire point of declocking in battle is to attack instantly. So while it's a big advertisement, so is the photon torpedo hitting the ship with it's battle shields down. –  Jul 15 '14 at 23:30
  • Where does "Space isn't cold, just well insulated" come from, please? Isn't space so extremely cold, everything in it would be bordering on absolute zero but for stellar radiation, which warms only what is not insulated? – Robbie Goodwin Dec 02 '20 at 10:21
  • @RobbieGoodwin -- Did you mean to post that in response to the original question, which included the line you quoted, rather than my answer? My guess would be that as you said, it was meant to be about stellar radiation. In any case, a true vacuum can't be assigned a temperature, one can only assign temperature to particles in space like interstellar hydrogen or the photons that make up the cosmic background radiation. And those are so thin that they don't drain heat very quickly (very low heat capacity) even when in contact with a body that's much warmer, so it acts like an insulator. – Hypnosifl Dec 02 '20 at 14:39
  • I don't think you're sure about the difference between heat and temperature. I do think you're not clear how far Mercedes or Samsung, for two, have advanced cloaking technology even in your lifetime. Of course they're still hugely primitive and why in your book would it be a problem to build on dailymail.co.uk/sciencetech/article-2110184/… or youtube.com/watch?v=ZetSRWchM4w in our next generation, let alone before Star Trek comes along? – Robbie Goodwin Dec 09 '20 at 20:05
  • @RobbieGoodwin - Why do you think I am confused about heat vs. temperature? Heat is thermal energy passing between one system and another (like a ship and its outside environment), and temperature differences between systems in thermal contact are part of the thermodynamic equations that determine the rate of heat transfer. The "cloaking" technology you mention has nothing to do with preventing heat transfer, only with trying to make an object's light emission at visible wavelengths look similar to its background. – Hypnosifl Dec 09 '20 at 20:29
  • @Hypnosifl You seem confused about heat and temperature because you explain heat as thermal energy passing between one system and another, and hope that justifies vacuum having neither… but that's going off topic here.

    Of course the technology I mentioned has nothing to do with preventing heat transfer, only with… uh… trying to make an object invisible against its background.

    Set up what fresh limits you like that had no place in your OQ and is the purpose of Star Trek's or anyone else's "cloaking" technology to make objects undetectable against their background, or what?

    Simples!

     – Robbie Goodwin Dec 09 '20 at 20:50
  • @RobbieGoodwin - A true vacuum has no temp., but as soon as their are any particles in it, including a photon bath (like that from the cosmic background radiation), you can assign a temperature, & one form of heat transfer is radiative transfer from the blackbody radiation emitted by any object with nonzero temp, a true cloak would need to block it. The systems you mention don't even try to strongly block thermal energy in the form of blackbody radiation (which at room temp would be in the infrared, not visible range), they just emit additional visible light to match a bright background. – Hypnosifl Dec 10 '20 at 00:15
  • @ Hypnosifl Of course the systems I mentioned don't attempt anything you're talking about… that's the point, not a problem.

    If you think "just" emitting anything to match a background can't work why not tell Mercedes and Samsung, etc, where they went wrong?

    They are succeeding, albeit with primitive technology.

    You seem to be saying they must be wrong because thermal energy can take the form of blackbody radiation.

    Why not Post the details when you can explain how their early efforts won't lead anywhere useful?

     – Robbie Goodwin Dec 10 '20 at 20:32
  • @RobbieGoodwin - It won't work because they aren't trying to hide a heat signature from blackbody radiation. Against a black background of space the technology would do nothing that a covering of ordinary black material would do (since the light emitters on the surface would have no reason to activate in this case). Any black covering can reduce the albedo of an object and hence the reflected light, but it won't reduce blackbody radiation which is the extra thermal radiation that'd be generated by a body even if it had an albedo of zero or if there was no incoming light to reflect off it. – Hypnosifl Dec 10 '20 at 21:17
  • @Hypnosifl Could you either explain how that matters, or drop it, or both?

    Whether you like it or not, Mercedes and Samsung, among others, have demonstrated early models of cloaking technology.

    When you can explain where they went wrong, please explain.

    Until then, why not accept their achievements, however primitive they seem to you?

     – Robbie Goodwin Dec 10 '20 at 21:31
  • @RobbieGoodwin - It matters because heat signatures in space (what the OP was asking about, not other forms of light emission like reflection of light from other sources) are due to blackbody radiation, and the technologies you mention wouldn't reduce blackbody radiation in the slightest compared to a simple opaque cover with no working emitters. If you think this technology could be adapted to reduce blackbody radiation by even a tiny amount (say 0.00001%) compared to a similar opaque cover but with the emitters turned off, can you explain how? – Hypnosifl Dec 10 '20 at 22:01