I was thinking about the heat dissapation problem of space ships, where space does not absorb heat to some neutral temperature very well. It does have a lot of ambient heat in the form of a nearby star, although i suppose the transfer of heat only works through the poor-transfer low-density space material is because the sun is very big and hot. This could suggest that dirt would make a good oven, being the least dense material that is shapeable. Metal, being very dense, should conduct things well, making insulators and insulations actually the non-deep non-dense mined materials, usually the cheapest ones. Also note that in a big space ship, the heat problem can be managed by mixing it with nuclear and human waste (although one of those is fertilizer), and jettisoning it out through a hole into space as a mix of hot shit.

I was thinking about the heat dissapation problem of space ships, where space does not absorb heat to some neutral temperature very well. It does have a lot of ambient heat in the form of a nearby star, although i suppose the transfer of heat only works through the poor-transfer low-density space material is because the sun is very big and hot.

The vast majority of heat transfer from the sun occurs through radiation, which doesn't depend on the density of the surrounding medium. Conduction and convection are more or less irrelevant in the near-vacuum of space. Unfortunately, the nature of the Black Body Radiation curve means that you need to be ridiculously hot to lose a significant amount of energy that way.

This could suggest that dirt would make a good oven, being the least dense material that is shapeable. Metal, being very dense, should conduct things well, making insulators and insulations actually the non-deep non-dense mined materials, usually the cheapest ones. Also note that in a big space ship, the heat problem can be managed by mixing it with nuclear and human waste (although one of those is fertilizer), and jettisoning it out through a hole into space as a mix of hot shit.
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I'm not quite sure i follow your thought processes here, (the sun is big, therefore dirt is a good insulator ) but yes, metals generally conduct heat well, and dirt, not so much. There are some awesome space-age insulators though, such as Aerogel which is not only an extremely good insulator, but ridiculously light too.

In any case though, dumping heat energy in a relatively impoverished environment such as outer space seems incredibly wasteful; starships would probably want to recycle as much heat as possible, using extensive reclaim systems to convert it back into useful energy. Same goes for waste materials.

Heat dissipation does become a problem for spaceships that generate a lot of excess heat and if space combat involved energy weapons. Since ultimately an energy based weapon is a heat based weapon. In cases like that heat dissipation would probably be most effectively done by a ship deploying a heat web. A heat web would consist of a large network of highly conductivity membranes or cables specifically designed to circulate the heat of the ship through itself.

Since ultimately an energy based weapon is a heat based weapon.

I disagree. If I want to turn on a LASER, in the real world, I'm going to turn on the most energy efficient one. Ideally, that would be a 100% efficient LASER where there is no heat generation at all. Heat generation is really a function of implementation rather than theory.
Example: revolving an object using electric motor. No cooling required (think at your washing machine). Revolving the same object using Internal Combustion Engine --> at least air cooling is required, unless we're talking about very small horsepower.

In cases like that heat dissipation would probably be most effectively done by a ship deploying a heat web.

I disagree. Although it is probably necessary to route heat to an absorbing system, the most effective way would be to convert it to chemical energy and store for reuse. Later, use the chemical energy to go back to a more convenient form. This is not sci-fi. Ever heard of "heat absorbers" (sometimes also called "puffers") and solar cooling? It's a bit expensive right now but viable.

Heat only lose when you have small amount of gas molecules near the surface of the ship gaining the energy and rush away. For energy based attack, then the same physics apply. The lack of air molecules of any kind prevent heat lost to vacuum. Thus, the ship will maintain it's heat. Energy attacks that generate unenclosed air molecules will have some heat lost as those molecules escape to space. However, most machines can be design to keep it's air molecules enclosed properly, so the heat will not escaping into space.

The only way to loose heat in a vacuum is through radiation. Have a look at "Black Body Radiation". This is the theory of how objects loose heat through radiation.

The amount of radiation emitted is due to the temperature difference between the source and what is out side the source (in this case empty space which is about 3 degrees kelvin above 0 degrees kelvin.

The rate of emission is not dependent on the density of the material, but the volume to surface area. An object with a high surface area to volume ratio will be more efficient at radiating heat than an object with a high volume to surface area ratio. What is also important is how fast you can move heat around inside the object (ship). An object with a low heat conductivity will quickly loose heat from its surface, but the heat inside will take a long time to reach the surface to be radiated. However, if an object has a high heat conductivity, then it can move the heat from its interior to its surface quickly, and will thus loose more heat quicker than a low conductive object (this is why a metal object left in the sun feels hotter than a plastic object left for the same period as the metal conduct the heat better and allows you to end up with more heat quicker in your fingers than the plastic object can).

And, lasers are a heat based weapon. The idea is to direct an amount of energy at a very focused point to heat up the target. IT is how this laser is tuned (frequency of the light) that can give certain effect. If the laser is tuned to the molecular vibrational frequency of the material, then it will cause heating. If it is tuned to certain electron frequency it will strip the electrons from the atoms and cause ionisation. Sure, a laser might not heat up the source if it is really efficient, but that is the point of a weapon. Why would you want to cause the weapon's effects to you and not the target?

Heat dissapation for space ships is a very serious problem due to the burning fuel and hot fires, so the engine parts do not melt or deform.

[quote name='TechnoGoth' timestamp='1299069853' post='4780963']Since ultimately an energy based weapon is a heat based weapon.

I disagree. If I want to turn on a LASER, in the real world, I'm going to turn on the most energy efficient one. Ideally, that would be a 100% efficient LASER where there is no heat generation at all. Heat generation is really a function of implementation rather than theory.
Example: revolving an object using electric motor. No cooling required (think at your washing machine). Revolving the same object using Internal Combustion Engine --> at least air cooling is required, unless we're talking about very small horsepower.

In cases like that heat dissipation would probably be most effectively done by a ship deploying a heat web.

I disagree. Although it is probably necessary to route heat to an absorbing system, the most effective way would be to convert it to chemical energy and store for reuse. Later, use the chemical energy to go back to a more convenient form. This is not sci-fi. Ever heard of "heat absorbers" (sometimes also called "puffers") and solar cooling? It's a bit expensive right now but viable.
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Unfortunately, the laws of thermodynamics prevent total reclamation of waste heat. There is always going to be waste, the best you can do is minimize it. Even electric motors (like that washing machine) generate waste heat, but most of the waste is transfered to the site of the electricity (i.e. the power plant). Something as powerful as a weapons-grade laser is going to produce a ton of heat, you'd be lucky to get 50% energy conversion efficiency.

The big problem for real life space vehicle and heat dissipation is sunlight. At the equator, the strength of sunlight is about 1000 wats per square metre. However, on Earth the atmosphere absorbs and scatters some of that light, which means that the amount of energy hitting a space craft is greater than 1000 wats/m[sup]2[/sup]. This makes them hot.

The big problem for real life space vehicle and heat dissipation is sunlight. At the equator, the strength of sunlight is about 1000 wats per square metre. However, on Earth the atmosphere absorbs and scatters some of that light, which means that the amount of energy hitting a space craft is greater than 1000 wats/m[sup]2[/sup]. This makes them hot.

If your ship has radiators (which all realistic ones will) you can turn them edge-on to the sun. That way the large radiators only present a tiny area to the sun, and can radiate freely. This may require the whole ship to be turned though, if the radiators can't be independently positioned.