# “Time travel” and temperature/energy [closed]

I'm sure people have heard many times of faster forward time-travel, likely involving speed and or gravity, bending the fabric of space-time. But what I would like to know, is if it is realistic to think that not only can you change space-time with energy, but also with temperature, and in what ways?

In comes my theory (likely breaking some part of thermodynamics unless energy is provided), of how you can move faster in the whole of space-time given that your area of space-time has less movement and/or less energy relative to the space-time around yours. Think of how motion effects the motion of space-time, faster speeds means faster space-time relative to the whole of space-time.

This means that, your space-time if near 0 kelvin, would be moving slower than the whole of space-time, as seconds to you could be (depending on the temperature) 1:30 to the whole of space-time. Because of this, I now ask, why is it impossible to continually take energy from a space in order to reach 0 kelvin or lower? I know that, simply being at a lower temperature means matter at a higher temperature will give energy to lower temperature matter. I read this: http://www.physicscentral.com/explore/action/negative-temperature.cfm and it says "negative temperatures are warmer" and gives experimental evidence towards my theory that negative temperatures are like dark energy in the fact that it must be stabilized by it's positive counterparts.

One can only think, given the current subject, that it would also make your space-time move backwards, theoretically meaning that either, (1), your time would now be as though you skyrocketed through time relative to the whole of space-time, or (2) that your time would be equivalent to negative time to the whole of space-time.

TL:DR:

I know gravity can effect space-time, same with motion, meaning faster forward time-travel is possible. But can 0 kelvin, meaning an extremely low amount of motion (as lower temperatures means matter/particles moves slower), invoke very low energy and energy capacity? If so, would negative temperatures invoke dark energy, and therefore a motion on those particles that is the same as kinetic energy, meaning time-travel through the space-time that the particles previously existed?

My mind considers this possible, only because it is in terms of math, including the fact that energy must be taken from something to be given to something. I want to contribute to a possible way of doing time travel if we can reach below 0 kelvin with conservation of energy in mind, considering anything dark so far has needed a non-dark form to stabilize.

## closed as unclear what you're asking by L.Dutch♦, Mike Scott, sphennings, Separatrix, ThucydidesAug 20 '17 at 22:04

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• Welcome to WorldBuilding. I hope you are aware that negative Kelvin and negative kinetic energy do not exist. So please clarify your question, else it can be closed for being unclear. – L.Dutch Aug 20 '17 at 6:42
• @L.Dutch I have added a source as a reference to clarify my uses of "negative kelvin" and "negative energy" – user41772 Aug 20 '17 at 7:02
• As you claim "...considers this possible, only because it is in terms of math..." - could you provide the equations you're thinking about? This would greatly help to support/disprove your idea. – dot_Sp0T Aug 20 '17 at 10:03

Firstly, there is such a thing as negative temperature, but it doesn't mean negative thermal energy. This can be used as guidance in considering the question of time travel and temperature.

In physics, certain systems can achieve negative temperature; that is, their thermodynamic temperature can be expressed as a negative quantity on the Kelvin or Rankine scales.

In colloquial usage, "negative temperature" may refer to temperatures that are expressed as negative numbers on the more familiar Celsius or Fahrenheit scales, with values that are colder than the zero points of those scales but still warmer than absolute zero.

A system with a truly negative temperature on the Kelvin scale is hotter than any system with a positive temperature. If a negative-temperature system and a positive-temperature system come in contact, heat will flow from the negative- to the positive-temperature system.1[2]

That a system at negative temperature is hotter than any system at positive temperature is paradoxical if absolute temperature is interpreted as an average kinetic energy of the system. The paradox is resolved by understanding temperature through its more rigorous definition as the tradeoff between energy and entropy, with the reciprocal of the temperature, thermodynamic beta, as the more fundamental quantity. Systems with a positive temperature will increase in entropy as one adds energy to the system. Systems with a negative temperature will decrease in entropy as one adds energy to the system.

Source: Negative temperature

The main issue with this concept is whether spacetime itself has a temperature. Also, whether any given temperature represents different rates of time passing or whether this influences the direction of time relative to global time. Here by "global time" this means time outside a given volume of spacetime or in terms of relativity a given frame of reference.

Generally temperature represents the thermal energy contained in matter. There is no way to measure if spacetime contains thermal energy or not. Also, there is no conceptual framework for considering that spacetime does have a temperature. Finally, there is no way of thinking about whether the speed of its passage or the direction of time is affected or not by spacetime in terms of its temperature.

As the OP said, it is known and empirically verified that high-speed motion (close to lightspeed) and strong gravitational fields "slows down" the passage of time. However, it is difficult to take the further conceptual step of linking the rate of time passing to a temperature of spacetime. Indeed as can be seen above in the section about negative temperature, a negative temperature may be paradoxically hotter than something with a positive temperature. If this logic is applied to spacetime, a region of spacetime at a negative temperature, assuming time and temperature are linked, may have time passing faster than a region at a positive temperature.

The British neurologist W. Grey Walter wrote a science-fiction novel, called Further Outlook (1956) in the UK, and published as The Curve of the Snowflake in the USA. This has a time-machine with an interesting hull that sounds like it was fractal, however, the temperature in the time-machine had fallen as a result of its journey from the future. While this is fiction, it suggest perhaps the relationship between time travel and temperature meant be different. Perhaps temperature associated with a time machine might rise or fall according to its direction through time. It is an idea worth entertaining if only for its intriguing possibilities.

A time machine could be imagined as a spacetime heating or cooling machine and as the temperature of spacetime is raised or lowered it travels into the future or past. For example, the normal temperature is zero degrees so raising the positive temperature makes around the time machine slow down relative to external time and carries its occupants into the future. Then lowering the temperature of the spacetime to become negative temperatures would also slow down time relative to external time and they would be carried into the past.

Is this scientifically realistic? Probably, not. But for the purposes of fiction it sounds sufficiently plausible to be an interesting way of imagining time travel. Scientist readers would be amused by its conceit. Non-scientist readers might think it sounds right. There's nothing wrong with that.

In summary, science as we know it does not indicate, suggest or allow for any possibility there is a temperature associated with spacetime. Even if there was, there is no way of reasoning whether a spacetime temperature would influence how fast or slow time passes or whether temperature could determine the direction of time and whether this could used for time travel. However, this does not stop the OP from postulating that temperature and spacetime are linked and that manipulation of the temperature of spacetime in any given volume could be mechanism to allow for time travel in any direction. But it could work well as science-fictional rationale for time travel.

• Thanks for some information and clarification. I suppose I could have added in the OP about my ideas of how temperature could effect time. The reason I thought about it in that way was because of how temperature effects the motion of the matter effected by that temperature, and higher temperatures is higher motion of that matter. Because of this idea, I ran into the thought of negative temperatures and how 0 kelvin, so far, has said to be when there is no motion. With that thought, it means no motion of matter, meaning it is effected by time slower or possibly not at all. – user41772 Aug 20 '17 at 7:51
• @user41772 There is no suggestion that time is changed when matter is at zero degrees absolute. The concept of spacetime having a temperature is currently undecidable. Although if someone can answer that definitely proves it either way that would be absolutely wonderful. If you can improve your question, please do so. There's nothing like a good challenging idea. – a4android Aug 20 '17 at 8:23
• Ok, so looking more into it, I can say confidently, that matter or particles (most chemistry effective particles) are affected by temperature, and temperature changes depending on the energy applied to the matter or particles. Motion (vibration) of matter or particles changes depending on the temperature, however, this does not mean space-time cares a single thing about temperature, as in the vacuum of space, where barely any chemically effective particles exist, temperature is very low, as it doesn't matter. The vibrations of the matter or particles can change space-time however. – user41772 Aug 20 '17 at 9:44