Space combat hangups

[Vebyast]

It's also not profitable yet. Anything that could be found on an asteroid is currently available on Earth cheaper than cost of mining it from the asteroid field,

There is actually one thing that you want to mine in space: Helium-3. Great fusion fuel if you can get it to react, but it's nearly impossible to find on earth because it's so light.

[Winnah]

A basic description of metamaterials. Can't mask IR, though still pretty damn effective (in theory).

[Swordslinger]

This is just absurd from a physics standpoint. The only way you get places in space, sort of crazy unrealistic technobabble about reactionless drives is to shoot shit out of the end of your rocket so you get pushed the other way. That fact isn't changing any time soon, and probably will be true forever.

Modern computers would be considered absurd and impossible 100 years ago. Imagine telling someone in 1850 that you'd be able to play a game in real time with someone on another continent. They'd think you were nuts. They literally could not fathom something like that ever being possible.

I seriously suspect that by the year 2150 (assuming humanity is still around), we'll see things technologically that people in this generation could not possibly imagine. It's really short sighted and arrogant to imagine that modern science is the be-all, end-all of knowledge.

As far as forces that don't produce a lot of heat, gravity is one. Beyond friction, gravity does not produce any heat in the acceleration it applies. So it's possible to add kinetic energy without producing a heat waste product. The fact that human made devices just aren't that efficient yet does not mean it can't be done. It probably won't be done in my lifetime, but I wouldn't write it off as impossible.

[Vebyast]

Modern computers would be considered absurd and impossible 100 years ago. Imagine telling someone in 1850 that you'd be able to play a game in real time with someone on another continent. They'd think you were nuts. They literally could not fathom something like that ever being possible.

I seriously suspect that by the year 2150 (assuming humanity is still around), we'll see things technologically that people in this generation could not possibly imagine. It's really short sighted and arrogant to imagine that modern science is the be-all, end-all of knowledge.

If you showed someone from 1850 a digital computer and an internet connection, it would be surprising, but they would not be able to put forth an argument for its impossibility. They never tested semiconductors, they never tested radio transmission, they never tested information theory, and so on.

By contrast, we have tested the laws of thermodynamics. We have math that describes how individual atoms radiate when heated and we have have demonstrated that every single observation we have ever made agrees with that math to within experimental error. If you showed us a hot object that didn't emit blackbody radiation it would directly and fundamentally contradict the most comprehensive, most powerful, and above all most accurate predictions ever made by humankind. There is a difference between "we can't imagine it" and "our math is pretty damn sure it's impossible".

As far as forces that don't produce a lot of heat, gravity is one. Beyond friction, gravity does not produce any heat in the acceleration it applies. So it's possible to add kinetic energy without producing a heat waste product. The fact that human made devices just aren't that efficient yet does not mean it can't be done. It probably won't be done in my lifetime, but I wouldn't write it off as impossible.

False. This only appears to be true because you don't deal with scales on which gravity is significant. When you do deal with significant gravity, losses to heat become obvious. For example, Europa is heated almost entirely by tidal forces from Jupiter's gravity. Particles that fall into black holes are compressed by gravity and momentarily accelerated to nearly the speed of light, producing hard X and gamma rays as they heat up.

And, again, though we'll undoubtedly be doing amazing things in 150 years, some of which we'd say are "impossible" using today's technology, none of those things will be impossible using today's physics, because we've experimentally verified our math.

[Swordslinger]

And, again, though we'll undoubtedly be doing amazing things in 150 years, some of which we'd say are "impossible" using today's technology, none of those things will be impossible using today's physics, because we've experimentally verified our math.

I don't think anything in our current physics would say that low heat, high energy transfers are impossible. Granted, we have yet to find one yet, but that's different from saying it doesn't exist.

Now granted, frictional heat is something that we'll probably never be able to actually eliminate (barring some kind of teleportation).

But processes like cold fusion aren't entirely unthinkable in modern science. Maybe one day there will be a breakthrough that produces efficient creation of energy without a great deal of heat.

[fectin]

none of those things will be impossible using today's physics, because we've experimentally verified our math.

classical physics, luminiferous Aether, Aristotelian physics, phlogiston, caloric theory, a half dozen different models of the atom...

Or did you want science in general, as opposed to pure physics?
Special cases often override general cases, like the relativity in your GPS. Obvious and extremely demonstrable theories (like Phlogiston) are dead wrong often enough (i.e. rarely, but at all) that asserting that something will be impossible in the future is ignorant.

Space stealth may very likely be impossible in the future. Here's some ways that could change, just offhand:
for black-body emissions:
- discovery of non-emitting material for hull coating
- method for directly controlling black-body radiation
for engine emissions:
- crazy magnetic wave propagation that the ship "surfs" on
- crazy gravity wave propagation that the ship "surfs" on
gamechangers:
- travel through "hyperspace" (whatever that means)
- all chaff, all the time (background disruption)
- etherealness (occupying some crazy parallel dimension)

I'm bored now. The tl;dr is that "impossible" is dumb.

[Grek]

Black body emissions are based on how light and electrons interact on a quantum level. There aren't exceptions to how it works. Likewise, magnetic and gravity waves (insofar as gravity is a wave) produce heat.

[Vebyast]

But processes like cold fusion aren't entirely unthinkable in modern science. Maybe one day there will be a breakthrough that produces efficient creation of energy without a great deal of heat.

I also suspect that we'll eventually find something extremely efficient; there are various versions of fusion that would accomplish that goal, for example. What we won't find is something that puts out no heat whatsoever. Remember, in space radiating any heat at all will make you stand out like a spotlight.

classical physics, luminiferous Aether, Aristotelian physics, phlogiston, caloric theory, a half dozen different models of the atom...

[...]

Space stealth may very likely be impossible in the future. Here's some ways that could change, just offhand:
for black-body emissions:
- discovery of non-emitting material for hull coating
- method for directly controlling black-body radiation
for engine emissions:
- crazy magnetic wave propagation that the ship "surfs" on
- crazy gravity wave propagation that the ship "surfs" on
gamechangers:
- travel through "hyperspace" (whatever that means)
- all chaff, all the time (background disruption)
- etherealness (occupying some crazy parallel dimension)

Again, you're confusing confirmation with refutation. We accepted those as long as we did not find any refutation, and eventually found experimental refutations and discarded them. An experimental refutation is absolute; if you have demonstrated that something doesn't happen, it will never happen, because the laws of physics never change.

Almost everything under "engine emissions" and "black-body radiation" has already been experimentally refuted. The only exception is the gravity-wave surfer, and every variation of that that I've seen requires the existence of negative mass or negative energy. There are a large number of ways to jam sensors, but all of them still let someone know roughly where you are; they only conceal your exact location. Etherealness or "hyperspace" are possible, but so implausible that they fall well into the realm of "a wizard did it"; after all, it could turn out all along that magic exists and we've never seen it only because nobody has ever said the words to cast fireball.

[fectin]

Black body emissions are falling is based on how light and electrons mass and gravity interact on a quantum level. There aren't exceptions to how it works.

Oh hey, an exception:
http://www.youtube.com/watch?v=A1vyB-O5i6E

I mean, it's not really an exception, but understanding it requires additional information, and it breaks from the normal behavior.

And there is no scientific theory which has been confirmed. Ever. It is unpossible to "confirm" a theory, you can only generate observations which are consistent with it, and fail to disprove it. That is a fundamental quality of science. Also, that's why theories like phlogiston were so successful: they racked up tons of experiments which failed to disprove them.

[hyzmarca]

Black body emissions are falling is based on how light and electrons mass and gravity interact on a quantum level. There aren't exceptions to how it works.

Oh hey, an exception:
http://www.youtube.com/watch?v=A1vyB-O5i6E

That isn't an exception. That's just a frog being held up by really powerful magnet. You might as well just pick up a frog with your hands and call it levitation. Doing so would be more energy efficient.

[Grek]

Also, that's why theories like phlogiston were so successful: they racked up tons of experiments which failed to disprove them.

Phlogiston was widely unsuccessful as a theory: it made no predictions to disprove. The theory of phlogiston worked by filling in what phlogiston was supposed to do after you saw the experiment. Nowdays, that shit doesn't fly, because people realize that a theory that doesn't make predictions in advance is as useless as having no theory at all.

The math that's used to resolve how black body emissions work does make predictions and, thus far, they've all been correct. While that's not "proof" that the math is both correct and complete, it is strong evidence for the theory that is going to require much stronger evidence than "boo hoo, science has been "wrong" before and I'm a fucking luddite, boo fucking hoo" to refute.

[Swordslinger]

I also suspect that we'll eventually find something extremely efficient; there are various versions of fusion that would accomplish that goal, for example. What we won't find is something that puts out no heat whatsoever. Remember, in space radiating any heat at all will make you stand out like a spotlight.

Avoiding heat radiation (assuming you don't have some crazy obvious thruster) may simply be a matter of good insulation and some kind of outer hull. It's possible to block most heat radiations by just putting up a cold barrier between the heat source and the sensor.

Obviously a stealth craft would have to be specially designed for that, but I'd hardly say it was impossible. Impractical maybe, but not impossible with futuristic developments.

[fectin]

Black body emissions are falling is based on how light and electrons mass and gravity interact on a quantum level. There aren't exceptions to how it works.

Oh hey, an exception:
http://www.youtube.com/watch?v=A1vyB-O5i6E

That isn't an exception. That's just a frog being held up by really powerful magnet. You might as well just pick up a frog with your hands and call it levitation. Doing so would be more energy efficient.

Beat you to it:

I mean, it's not really an exception, but understanding it requires additional information, and it breaks from the normal behavior.

I probably could have chosen something simpler for "more than one force acting on an object, but really: who doesn't want to see a levitating frog?

Also, that's why theories like phlogiston were so successful: they racked up tons of experiments which failed to disprove them.

Phlogiston was widely unsuccessful as a theory: it made no predictions to disprove. The theory of phlogiston worked by filling in what phlogiston was supposed to do after you saw the experiment. Nowdays, that shit doesn't fly, because people realize that a theory that doesn't make predictions in advance is as useless as having no theory at all.

That's odd. If Phlogiston doesn't make predictions, how could calorimetry disprove it? (Aside: phlogiston isn't so much wrong as it is useless. If "phlogisten" means "lack of oxygen", all the old equations work out fine. It's exactly like how you can consider holes flowing instead of electrons. It just doesn't generate any useful results, and is stupidly confusing.)

The math that's used to resolve how black body emissions work does make predictions and, thus far, they've all been correct. While that's not "proof" that the math is both correct and complete, it is strong evidence for the theory that is going to require much stronger evidence than "boo hoo, science has been "wrong" before and I'm a fucking luddite, boo fucking hoo" to refute.Our current understanding is perfect, and will never be improved, and anyone who says otherwise is a Luddite.

I'll pretend to respect your opinion here, but that level of blind traditionalism is pretty ignorant. Also, you might want to check your definitions; "Luddite" usually doesn't apply to the side advocating for progress.

The scientific method is not a single recipe: it requires intelligence, imagination, and creativity.[48] In this sense, it is not a mindless set of standards and procedures to follow, but is rather an ongoing cycle, constantly developing more useful, accurate and comprehensive models and methods. For example, when Einstein developed the Special and General Theories of Relativity, he did not in any way refute or discount Newton's Principia. On the contrary, if the astronomically large, the vanishingly small, and the extremely fast are removed from Einstein's theories — all phenomena Newton could not have observed — Newton's equations are what remain. Einstein's theories are expansions and refinements of Newton's theories and, thus, increase our confidence in Newton's work.

One of the key features of science is that we continuously refine our understanding of natural phenomena. That's not to say we toss things out willy-nilly, but observable traits are often generalizations, which don't hold up perfectly. That's true with nearly any theory you come up with: The Ideal Gas Law is more useful and less accurate than atomic theory, which is more useful and less accurate than Quantum Theory. Maybe String Theory underlies that, I don't know. It doesn't seem to have any observable effects yet. The point is, there's always a more detailed explanation of what's happening.

tl;dr: you're a tool. Wrap yourself in a fractal-surfaced solid osmium sphere kept at 0 Kelvin and you don't emit anything.

[tzor]

you're a tool. Wrap yourself in a fractal-surfaced solid osmium sphere kept at 0 Kelvin and you don't emit anything.

And you're a fool. In order for a fractal-surfaced whatever to remain at 0 Kelvin it has to be a perfect white body (otherwise it will warm up to the background radiation level or higher because it is constantly being bombarded by starlight) and that means it perfectly reflects all light aimed at it. Mirrors in space are easy to detect.

And it begs the problem. Anyone wrapping themselves in a white body has to deal with the problem of how to eat their own energy. Your internal temperature can go to infinity inside your white body shield.

But hey, on the plus side, a pure white body is impervious to any EM emergy weapons! So if you only use lasers, who they fuck cares if they know you are there. (I'm rubber; your glue; what you fire at me will reflect back to you!)

[tzor]

By the way, if you want to push the envelope of real science-fiction, the only possible method is the use of a high magnetic slip wave propagation method which requires a magnetic field so fucking huge that the whole question of hiding from detection becomes moot. A simple magnetometer could detect the magnetic wave signature.

[DSMatticus]

Fectin, again, "science might be wrong" is a bullshit, annoying way to go. There are things we have demonstrated to be almost certainly true in laboratories, and any presupposition that begins with those being wrong (like simultaneously being able to not give off heat and not cook yourself to a delicious golden brown) is stupid and should be ignored.

There is never going to come a day when someone shows 2=3; perfect understanding is totally a possible thing, and there are physics questions about which we for all intents and purposes have a perfect understanding. Because we have something all those other idiots didn't have; evidence. Lots of it. Ridiculous amounts of it.

Avoiding heat radiation (assuming you don't have some crazy obvious thruster) may simply be a matter of good insulation and some kind of outer hull. It's possible to block most heat radiations by just putting up a cold barrier between the heat source and the sensor.

Man, you're like... on the same conversation loop as everybody else, but a quarter-turn back. Fectin proposed something like this, and this is where physics wags its finger at you. Heat doesn't stop existing when you insulate and block it, it just stops moving. And if it stops moving, that means you are collecting it. Lots of it. This sort of stealth turns your own ship into molten slag. And that's assuming you actually have a perfect insulation strategy that stops the outer barrier from heating up, too. With an imperfect insulation strategy (as will always exist), you'll actually have to run your power plant to power a heat pump that will actively cool your outer hull. But that produces even more waste heat! You're invisible, but you've got all this excess waste heat and what are you going to do?

Your options are melt or vent, so you're going to vent, and that means the venting will be completely and utterly obvious. You'll choose to vent away from the enemy, of course, but establishing a complete sphere of vision in the way of a sensor network is ridiculously easy and cheap, comparatively, so you'll be spotted even if you vent away from the destination.

[Winnah]

A major issue with any kind of cloaking technology is assymetry. No point making yourself invisible if it renders you blind, deaf and mute. Any material that has been engineered to allow particles to 'wash' around them probably won't be unidirectional.

At the very least, you're going to want sensors and communications exposed. Same goes for any kind of exhaust propulsion.

Your best kind of stealth would be obsfucation or disguise. Either produce so much noise that nothing in an area can be detected with accuracy, or conceal your emissions so that they appear to be something else.

[A Man In Black]

Fectin, again, "science might be wrong" is a bullshit, annoying way to go. There are things we have demonstrated to be almost certainly true in laboratories, and any presupposition that begins with those being wrong (like simultaneously being able to not give off heat and not cook yourself to a delicious golden brown) is stupid and should be ignored.

Unless it makes for a better game or a better setting, where it can be done with plotonium reactors with and an arbitranium outer shell.

Hard SF is not the only kind of SF, nor is it an inherently superior form of SF.

[DSMatticus]

That is definitely not what started the space stealth discussion. It's a discussion about what is and isn't possible. Not what can and cannot be put on paper. Scientifically, you can't have stealth. But technowizardry will get you anything you want, and it'll probably even make for a better story.

Really, any interesting sci-fi story should probably propose the existence of fixed rate, infinite energy sources (and similar ways of disposing of energy). Once you have those sci-fi can get pretty interesting and still be mostly realistic from its premises.

[Vebyast]

Yep. I personally like single-point-of-departure hard SF, where the author gives the world one single, really well-thought-out piece of technowizardry. For example, that energy generator/dumper idea that DSMatticus has would give you relativistic combat, relatively short-range, high-power combat (because you have to be really close to have any chance at all at hitting something that can accelerate to .9c in a couple of seconds), and easy stealth in space.

Another one would simply be the ability to transform energy around losslessly and at a short distance (several meters). That gives you shields, stealth, and some nifty weapons and sensors.

[fectin]

you're a tool. Wrap yourself in a fractal-surfaced solid osmium sphere kept at 0 Kelvin and you don't emit anything.

And you're a fool. In order for a fractal-surfaced whatever to remain at 0 Kelvin it has to be a perfect white body (otherwise it will warm up to the background radiation level or higher because it is constantly being bombarded by starlight) and that means it perfectly reflects all light aimed at it. Mirrors in space are easy to detect.

Not true, on two counts:
First, the first thing that will happen is the above-zero temperature propagates inward, before it gets warm enough for significant radiation (it's a function of T^4, so you've got a while). Then whatever phlebotinum you're using to keep the inside cool in the first place will eat that excess heat.
Second, you're not going to be doing a lot of reflection anyway. The surface geometry is going to eat most/all of your inbound radiation, and the heat that makes is wicked away as above.

Yes, that does mean there's a limit on how long you can maintain this. But if something can be done at all, doing it better/longer/cheaper is just engineering. Whatever the constants on your heat storage are, you can store heat as a function of volume (maybe by vaporizing and de-vaporizing tantalum? Or however else) and you eat new energy as a function of area, which means that your time goes up as you get bigger; there's a size where it's possible, and all you have to do is drive that size back down. (Assuming, of course, that we haven't found a way to do something crazy use heat directly to split off antimatter, then store that as fuel.)

Of course, it's begging the question anyway, by assuming you can get a fractal surface, and a 0K sphere. But it's also against an artificially high standard; you don't need zero emissions, just low enough to escape detection.

Fectin, again, "science might be wrong" is a bullshit, annoying way to go.

But so is "we already have every technology and all the knowledge that we ever will have", which is at least as accurate a summary of your position as you've just given of mine.

[Vebyast]

But it's also against an artificially high standard; you don't need zero emissions, just low enough to escape detection.

Low enough to escape detection == zero. If you are even the slightest bit warmer than the CMB you will be seen, and you will be seen quickly. For example, we've spotted brown dwarves - stationary brown dwarves dozens of light-years away - that are less than 500 Kelvin.

Fectin, again, "science might be wrong" is a bullshit, annoying way to go.

But so is "we already have every technology and all the knowledge that we ever will have", which is at least as accurate a summary of your position as you've just given of mine.

We don't know everything, we don't have technology. However, there are some things that we have experimentally determined to not happen. We do have that knowledge and that knowledge will never change. We have experimentally determined that things in vacuum and in the same gravitational field fall at the same rate, we have experimentally determined that photons behave simultaneously as waves and particles, and we have experimentally determined that black body behavior holds even for singularities and individual subatomic particles at nearly zero kelvin. Your arguments read like you're arguing that gravity doesn't exist.

[Username17]

You're positing FTL travel. What things you use in battle are pretty much entirely dependent upon that. With ships moving around faster than light, the information they get about the world around them is out of date, meaning that laying sublight mines is very plausible as a combat style. They'll move into them before they see them, because both the ship laying the mines and the ship getting hit by the space charges are moving faster than light.

But whatever your FTL system runs on pretty well defines what weapons do and do not work. For example: if you go faster than light by flying into a nightmare realm and popping out elsewhere in the galaxy, it might literally be necessary for your navigator to have a psychic sword fight with the navigator of the other ship. If ships go faster than light by bending gravity mirrors, you might fight them by attaching nuclear bombs to nearby asteroids to attempt to break their gravity mirror calculations by having nearby semi-random high energy events.

You cannot discern what the combat techniques should be like without determining what your FTL bullshit tech is like. Because you're declaring a black box that completely changes the assumptions of basic physics.

-Username17

[fectin]

But it's also against an artificially high standard; you don't need zero emissions, just low enough to escape detection.

Low enough to escape detection == zero. If you are even the slightest bit warmer than the CMB you will be seen, and you will be seen quickly. For example, we've spotted brown dwarves - stationary brown dwarves dozens of light-years away - that are less than 500 Kelvin.

Okay. So the upper bound of blackbody emissions is 5.67 * 10^-8 * T^4 watts/square meter. You tell me what the sensitivity of your detector is, and I'll tell you how low temperature needs to be for you not to see it. That number will never be zero. If you want sensitivities in a spectrum, you'll be worse off, since it'll be less across any window than the total power, but then you can use Planck's Law.
Further, surface geometry and material emissvity come into play, and drop your actual emissions as much as two more orders of magnitude.

Fectin, again, "science might be wrong" is a bullshit, annoying way to go.

But so is "we already have every technology and all the knowledge that we ever will have", which is at least as accurate a summary of your position as you've just given of mine.

We don't know everything, we don't have technology. However, there are some things that we have experimentally determined to not happen. We do have that knowledge and that knowledge will never change.

I'm not interested in picking a fight over whether we are all dreaming, and all our results are observer error. That is a stupid and useless fight.

We have experimentally determined that things in vacuum and in the same gravitational field fall at the same rate,

This is false. We have experimentally determined that things in vacuum and in the same gravitational field fall at the same rate unless acted on by another force (e.g. an EM field).
Everyone seems to be asserting the equivalent of " a dropped object will always hit the ground, no matter what", and I keep responding with "you can engineer a situation where it doesn't."

we have experimentally determined that photons behave simultaneously as waves and particles, and we have experimentally determined that black body behavior holds even for singularities and individual subatomic particles at nearly zero kelvin.

Ehh, sort of. We have a whole bunch of experimentally determined material- and surface -based constants in there. But even taking everything at face value, it doesn't even matter unless you also assume that everything is a perfect blackbody radiator, that there is no more detailed/more accurate description of blackbody radiation, and that no other forces can interact with that radiation.
That's begging the question pretty hard.

Your arguments read like you're arguing that gravity doesn't exist.

And the counterarguements read like "lol, gravity is always -9.8m/s/s. Because science measured it."
It's not that there are "exceptions" to gravity. But a superficial understanding of gravity's effects is not sufficient for even basic ballistics, and a deeper understanding tells you how to screw with those results (get closer to or further from dense objects).

As a quick exercise, if our understanding of gravity is perfect, and blackbody radiation is an inevitable and eminently observable phenomenon, what is dark matter?

[Vebyast]

Your arguments read like you're arguing that gravity doesn't exist.

And the counterarguements read like "lol, gravity is always -9.8m/s/s. Because science measured it."
It's not that there are "exceptions" to gravity. But a superficial understanding of gravity's effects is not sufficient for even basic ballistics, and a deeper understanding tells you how to screw with those results (get closer to or further from dense objects).

And so on and so on. However, beyond a certain point, our theories, no matter how incorrect in the absolute sense, are still good enough. We use Newton's laws to send probes to Jupiter because they're good enough, even though they'll accumulate a few meters of error along the way. We use Einstein's laws for almost everything else, even though they break down around singularities and dark matter/energy. We use them because they're good enough and because they describe the bits of reality we're concerned with to an acceptable degree. More importantly, we can carry out experiments that demonstrate exactly where and in what way they fail, and we can draw a line and say "this theory is good enough for everything on this side of the line, because the theory agrees with observations well enough for our purposes". In this argument, that line is drawn well past basic black body radiation.

You cannot discern what the combat techniques should be like without determining what your FTL bullshit tech is like. Because you're declaring a black box that completely changes the assumptions of basic physics.

Agreed here. FTL is a major point of departure from real physics, and you need to think very carefully about exactly how the rest of reality is going to follow that departure.