I'm working on a version of wormhole-based FTL travel, and one of the side effects of passing through the wormhole is going to be instantaneous heating of every molecule of the thing passing through. The heating works by dumping a specific amount of thermal energy into every molecule of the object passing through the wormhole, and the rise in temperature is thus affected by the specific heat capacity of each molecule.

In a previous question I asked about the maximum amount, starting from normal body temperature, that one can suddenly heat a human's entire body by. It turned out to be rather small, not much more than 1°C above normal. We can do a bit better than that by giving people mild hypothermia beforehand, so we're going to say that, as we can safely send humans through it, this wormhole raises the temperature of human flesh by about 4°C. This means that it dumps about 14 kJ/(kg*°C) of thermal energy into everything that passes through it.

This means that some substances which have much lower specific heat capacities would be heated by a substantial amount. The air in the spacecraft, for example, would be heated by about 14°C. Copper wiring would go up by over 36°C. Any spacecraft parts made of Tungsten would go up by almost 105°C. These temperature increases could cause the spacecraft to begin to leak or cause other dangerous situations. So, what major issues would there be with suddenly dumping 14kJ of heat into every kilogram of a spacecraft?

To clarify, the spacecraft in question is specially designed for this type of transition. The question is asking what would have to be designed differently and what could still go wrong.

  • $\begingroup$ I didn't got it. Total body temperature rise is 1°C or 4°C? $\endgroup$
    – ksbes
    Oct 29, 2019 at 10:04
  • $\begingroup$ @ksbes 4°C because we can give people mild hypothermia first. $\endgroup$
    – Gryphon
    Oct 29, 2019 at 12:30
  • $\begingroup$ I know this is the other topic but hypothermia is going to cause almost the same problems. > When your body first drops below 98.6˚F (37˚C), you may experience: * shivering * an increased heart rate * a slight decrease in coordination * an increased urge to urinate. When your body temperature is between 91.4˚ and 85.2˚F (33˚ and 30˚C), you’ll: * decrease or stop shivering * fall into a stupor * feel drowsy * be unable to walk * shallow breathing $\endgroup$
    – Vogon Poet
    Oct 29, 2019 at 13:33
  • $\begingroup$ But most importantly, the rapid change in core body temperature is going to beat the crap out of their system. They will be disoriented. This is the kind of trip you want to take in bed or stasis with the ship on autopilot. I wouldn’t trust any living organism at the controls. $\endgroup$
    – Vogon Poet
    Oct 29, 2019 at 13:35

2 Answers 2


Almost everything in your spaceship can be specifically designed to handle your temperature increase without any noticeable side effects. It’s just a matter of engineering it properly. Electronics can simply use a different conductor, such as metal impregnated ceramics. It’s a challenge, but doable. The areas you really need to be concerned about are chemical reactions. Since we have no idea what resources your spaceship has, we’re guessing at least you have some form of chemical fuel.

Fuel: The chemical reactions needed to propel your craft will be sensitive to changes in temperature. Often modern spacecraft use cryogenic fuel for maximum energy density, this kind of fuel system will obviously fail catastrophically (remember everything that touches the fuel is heating up). But even gasoline, kerosene, or diesel reactions will change to some degree if you preheat the fuel. Some reactions improve, others go the other way. It depends on your fuel.

Rations and provisions: Any form of food or rations will essentially get “microwaved” so the crew has to come up with a plan to remove energy from those items and plan the meals appropriately.

Medical implants: Absolutely anything inside your crew members needs to be considered. This means titanium pins for bone repair, dental fillings, pacemakers or other electronic prosthetics, etc.

Clothing: Did your spacesuits have titanium zippers inside? Aluminum? The spacesuits need to be engineered just as carefully as the ship, however people will be inside of them. Make sure you are not building a microwave oven for the crew! And don’t forget the boots!

Jewelry: Earrings, necklaces, wedding rings, nose or tongue studs. Think “all metal = bad” if it touches the crew.

Glass and other ceramics: Brittle ceramics may crack with heating. Everything made with silicate or hard ceramics needs to be designed not to crack under heating.

Plastics: Usually metal parts have plastic handles or coatings, which may melt and emit toxic fumes. This is another design challenge your engineers need to tackle.

  • $\begingroup$ "this kind of fuel will obviously fail catastrophically." it is entirely non obvious. Liquid hydrogen has a pretty high SHC. Even liquid oxygen, which has a lower SHC isn't going to get much of a temperature rise. Unless you imagine that fuel tanks are operating right on the very edge of stability, for some reason? Frozen food wouldn't even defrost, unless it was already too warm and close to the limit. Etc etc. $\endgroup$ Oct 29, 2019 at 12:50
  • $\begingroup$ I’m imagining that the fuel is in a container that is not made of fuel, so the entire fuel system is contributing heat. Food is occasionally kept in containers (a microwave oven is a container, or vice-versa). none of these effects happen in a vacuum (pardon the pun). $\endgroup$
    – Vogon Poet
    Oct 29, 2019 at 12:52
  • $\begingroup$ You didn't actually mention tanks though. Probably worth editting that in. Wrapping the tanks in carbon fibre to withstand transient pressure fluctuations caused by brief heating where the contents contact the wall of the tank is probably sufficient there. $\endgroup$ Oct 29, 2019 at 12:56

The first major issue would be electric and electronic failure.

Since high-loaded processing units (central, graphical, etc) work at temperatures near to maximum (50-60-70C), rising it by 20-30C would stop and even damage them.

Many parts of high-energy electric network also produce heat (transformers, bad contacts) and superheating can damage them or activate fuses or other security measures. Spaceship can loose energy in random subsystems.

Second major issue are liquids and gases.

Here the main point is how fast this "sudden heat" dumps in. If it is really instantaneous - it's bad news. This would create a sudden rise in pressure and shockwaves. Many hermeticaly sealed full liquid containers would crack or explode (medicine, water pipes, fuel lines, life-supporting equipment, full fueltanks).

Air pressure would jump by 7%. This would cause a barotraumas to humans and may damage some non-structural elements of the spaceship (shatter glass, break inner doors, lights, monitors, damage ventilation equipment). This effect would not be that devastating since air is all around these objects, but in some unfortunate cases (when shockwaves from corners meet at or near objects) that may happen.

The third major issue would be fine mechanics.

Solids would also experience these shockwaves, but structural metal elements (like hull or engines) would not be damaged. But say doors (airlocks) and turbines, motors, other complex equipment can get stuck and/or break. Rotating turbines (say in engines or generators) would do it violently.

The main problem with this heating that it is sudden: it would be like a strike, like a small explosion all over the place

  • $\begingroup$ Air pressure jumps by 7% everywhere in the craft, inside the body and out, so why would barotrauma occur? There is no pressure differential. You might get a shockwave from the sudden thermal expansion of materials on the ship, but I don't see why a relatively minor, sudden, but uniform increase in air pressure would affect much. $\endgroup$ Oct 29, 2019 at 13:50
  • $\begingroup$ @NuclearWang because of shockwave hiting lungs from inside (and body outside). I can't assume what exact effect would be (I am not a medic), but that would not be good. $\endgroup$
    – ksbes
    Oct 29, 2019 at 14:14
  • $\begingroup$ @ksbes You're working from an invalid assumption, I think... If this is how wormhole travel works, the people designing the spacecraft would KNOW this, and the craft would have been designed from the outset to take that kind of heat load. All your fluid systems would have pressure relief systems, your electronics would be running 30C below danger temp, etc etc. You can engineer away almost all those problems if you know they're coming. $\endgroup$ Oct 29, 2019 at 19:05

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