The End Of The Scifi Arms Race

[Spacescifi]

 

The ultimate space weapon I think would be an antimatter particle beam fired at 99% the speed of light with a density of a kilogram fired gradually over 60 seconds.

Any asteroids or spacecraft in the beam's path should be properly wrecked.

 

Any spaceship firing it would either need to be a very large vessel to spread rather than concentrate the waste heat, or have massive radiators... at least if using modern understanding of science.

 

I do not believe such a weapon can be countered with any method outside of using massive asteroids as shields,  which would only last so long.

 

Besides dodging, I cannot think of any counters. Missiles would be wrecked about a lightsecond away as well as anything else.

 

It's like a laser... only it blasts stuff instead.

 

What do you think?

 

[Treveli]

(looks through his 'Superweapons of the Multiverse' cards, lays one on the table)

High-c Bucket of Sand.

Sand blasts everything. Ships, stations, planets. Trillions of kiloton-range detonations. And the only warning you get is a millisecond or two before it hits you. Cost- one freighter, few tens of thousands of tons of dirt.

[Spacescifi]

1 hour ago, Treveli said:

(looks through his 'Superweapons of the Multiverse' cards, lays one on the table)

High-c Bucket of Sand.

Sand blasts everything. Ships, stations, planets. Trillions of kiloton-range detonations. And the only warning you get is a millisecond or two before it hits you. Cost- one freighter, few tens of thousands of tons of dirt.

 

Arguably cheaper than my solution... or is it? The energy required to shoot sand at that speed would make your vessel retrothrust ever time you fired the superweapon! And your vessel would need to be huge, not unlike my vessel.

 

In a shoot out between our vessels, either one could win, but I have an advantage in that antimatter beams hitting oncoming sand would obliterate it.

[Guest]

Another bucket of sand would do that, too. Relativistic antimatter weapons are a waste (this includes antiparticle beams). TBH, so are most relativistic weapons. The energy requirements to accelerate a massive object to 0.99c is gigantic. Forget having a ship fire it, if you want a relativistic weapons, you're building a fully functional sublight starship and throwing it at the enemy. Dodging is impossible (unless the target is always dodging, which is a valid tactic), but so is aiming, and acceleration takes so long you'll be firing from an adjacent star system. Oh, and you better have a very good guidance algorithm, because making meaningful course corrections at 0.99c is hard. Given this, the only thing such a weapon has a chance of hitting is a planet. It could possibly work as a planet killer, but by the point you can afford that kind of thing, your civilization hits Kardashev Type 2, and in this case, there are two possible scenarios: you're fighting a non-Type 2 enemy, in which case they're screwed anyway and there are better ways of dealing with them (unless you want to make a point), or you're fighting another Type 2 or 3 civ, which can preemptively move planets to account for this threat, if they think you might shoot a relativistic weapon at them. It's quite simple, too, just swing an asteroid close by to change the planet's orbit slightly. At interstellar distances, even a small error means missing completely. 

TL;DR: Relativistic weapons aren't so great, because there's no such thing as free lunch. All that energy has to come from somewhere, and getting that much kinetic energy into an object is hard. Even if you do that, aiming the thing is also hard.

[kerbiloid]

A portable improbabilizer.
Makes the enemy's existence improbable.

Upd.
Iirc, in the Lem's sci-fi was named "depossibilitator".

Edited January 4, 2020 by kerbiloid

[KSK]

How about two astronauts competing to put on their spacesuit gloves? That would be a proper end-of-the-arms race.

[kerbiloid]

Armwrestling for the only pair of gloves.

[Scotius]

+10 to Diplomacy.

Why wage costly wars, when you can sweet-talk potential enemy into becoming your friend? Or even joining you?

[Okhin]

Also, whatever explodes (your stuff, the enemy stuff, passer by) leaves a debris field. And the one who won the fight (or the last one standing, or passer by) have to either mark the space as dead, or collect each and every parts of speck of dust moving at high velocity in the vicinity in order to being able to use the space again.

Worse, since there was explosions, those speck of dust which can wreck havock on anything that travels through it, they actually expand. Meaning the more you wait for you cleaners crew, the more dead space you're creating. Radioactive wasteland can be shielded against , but not the cloud of debris created (best case is some ablative tech, so it cost money, or regenerative tech, but then it cost mass which is money) by a battle.

You don't want to blow up things in space. You want to disable them. Blowing up stuff is a last resort (and can be used in asymetric warfare situation). You want to disable the enemy battleships without having to big a shrapnel cloud moving at high speed in space. So I would assume, boarding parties are in order. As well as diplomacy, spycraft and, at some point, information warfare.

Why fight a war when your opponents think you already won it and surrender ?

Don't blow excrements up in space. Or clean after you.

Thank you, the space janitor team.

[kerbiloid]

2 hours ago, Scotius said:

+10 to Diplomacy.

Why wage costly wars, when you can sweet-talk potential enemy into becoming your friend? Or even joining you?

Spoiler

A combat headset.

[Guest]

51 minutes ago, Okhin said:

Don't blow excrements up in space. Or clean after you.

Thank you, the space janitor team.

Actually, this isn't a problem. You see, an explosion causes the fragments to fly off at high speeds. Thus they tend to leave the area of the explosion. Space is big, and a "speck of dust" is incapable of doing much damage, especially if hypervelocity, to something with even a basic Whipple shield. In particular, relativistic weapons would likely cause fragments of whatever was hit to leave the system altogether. Nuclear explosions would do the same thing. Don't believe what they say about Kessler syndrome, it's a bogus theory, as far as the most popular version is concerned. 

In fact, it's disabling that's likely to cause problems. Because it leaves a large piece of debris, or possibly several large chunks that's, more or less, in the same orbit it was in when it was working. Kinetic impacts 

2 hours ago, Scotius said:

+10 to Diplomacy.

Why wage costly wars, when you can sweet-talk potential enemy into becoming your friend? Or even joining you?

What if you can't? If you're competing for something which is both vital and too limited to be shared (arable land is a common historical example), then how else do you decide who gets it?

[Scotius]

1 hour ago, Dragon01 said:

What if you can't? If you're competing for something which is both vital and too limited to be shared (arable land is a common historical example), then how else do you decide who gets it?

We are talking about interstellar civilizations here. With entire star systems worth of materials and space accessible. At this point if you lack anything, you are either lazy or extremely unlucky. Barring the discovery of truly unique resource (coughSpicecough), waging a war for something will probably cost more than getting it from somewhere else without bloodshed.

[Spacescifi]

24 minutes ago, Scotius said:

We are talking about interstellar civilizations here. With entire star systems worth of materials and space accessible. At this point if you lack anything, you are either lazy or extremely unlucky. Barring the discovery of truly unique resource (coughSpicecough), waging a war for something will probably cost more than getting it from somewhere else without bloodshed.

 

True but that still leaves uniquely human reasons for war that animals which fight over resources would never consider... idealogy and religion. I mean the closest animals even come to this is pets fighting each other for the affections of a human, but idealogy is rather absent, since animals are already partially hardcoded with instincts geared more toward survival and reproduction than free thought.

War decides who's idealogy reigns supreme, or which even continues to exist.

One can kill an idea or concept, but they tend to come back.

 

History is full of this.

Edited January 4, 2020 by Spacescifi

[kerbiloid]

58 minutes ago, Scotius said:

We are talking about interstellar civilizations here. With entire star systems worth of materials and space accessible. At this point if you lack anything, you are either lazy or extremely unlucky. Barring the discovery of truly unique resource (coughSpicecough), waging a war for something will probably cost more than getting it from somewhere else without bloodshed.

Even moar.
When two civs meet each other, both of them are already highly skilled in molecular engineering and genetic programming, so they will realize that the creature they see is an alien only by incompatible QR-code on the forehead.

[Okhin]

2 hours ago, Dragon01 said:

What if you can't? If you're competing for something which is both vital and too limited to be shared (arable land is a common historical example), then how else do you decide who gets i

Arable land is not a common hisorical example. It was an excuse for us, Europeans, to mess with the rest of the world. You didn't needed arable land. You wanted control over it and power. Not arable land. If you're not feeding everyone on the land you assert control over you're doing one of those two things:

- You're not even trying. There might be a better way to feed everyone with what you have. It can be promoting some birth control system, a more efficient diet (less meat, more fibers etc), or doing more science to improve energy efficiency conversion, which lead to a higher amount of proteins per watt invested in growing them (meaning you either spend less of those protein for the same amount of energy, or that the overhead cost of producing more energy is compensated).

AND/OR

- You're locking people on the territory you control, to a point the population density goes up the roof and you need to import some goods, and no one want to trade with you. Locking people can be done in a lot of way, most of them being political. Nationalism is one of them, as Communism is. But basically you lie to the people who happenned to live on the land you assert control over to force them to stay there, despite the fact that there's some more land elsewhere where they can go without murdering someone else.

In the end, there's no resources exhaustion. There's just people who does not recognize the other as people or want to show off by getting hegemonic.

Oh, and disabling things, makes them salvageable. So they're reusable, at least as bare metals. They're not really waste (but yes I agree, it has a cost and need some planning, but you can move that).

[Treveli]

14 hours ago, Spacescifi said:

 

Arguably cheaper than my solution... or is it? The energy required to shoot sand at that speed would make your vessel retrothrust ever time you fired the superweapon! And your vessel would need to be huge, not unlike my vessel.

 

In a shoot out between our vessels, either one could win, but I have an advantage in that antimatter beams hitting oncoming sand would obliterate it.

The Realativistic Sand Blaster is far simpler than you're thinking. All I need is a simple freighter that can haul a couple tens of thousands of tons (20k to 30k if I'm remembering right) and has appropriate power and propulsion (since this is sci-fi, quantum power taps and a singularity drive).

And I'm not getting in a shoot out with your ship. I'm going after what your ship exists to protect, and needs to function. The planets you come from. This is an interplanetary WMD, to be used when all diplomacy has failed, you're to dangerous to leave alive, or both.

This is all from one of Ian Douglas's hard sci-fi novels. Haven't read it in years, but it made me wonder why anyone would want to build superlasers.

[scottadges]

8 hours ago, kerbiloid said:

A portable improbabilizer.
Makes the enemy's existence improbable.

Upd.
Iirc, in the Lem's sci-fi was named "depossibilitator".

Thank you, Mr. Douglas Adams (or maybe he was channelling Stanislaw Lem?)

4 hours ago, Okhin said:

without having too big a shrapnel cloud moving at high speed in space

So... bad?

 

Edited January 4, 2020 by scottadges

[Spacescifi]

17 minutes ago, Treveli said:

The Realativistic Sand Blaster is far simpler than you're thinking. All I need is a simple freighter that can haul a couple tens of thousands of tons (20k to 30k if I'm remembering right) and has appropriate power and propulsion (since this is sci-fi, quantum power taps and a singularity drive).

And I'm not getting in a shoot out with your ship. I'm going after what your ship exists to protect, and needs to function. The planets you come from. This is an interplanetary WMD, to be used when all diplomacy has failed, you're to dangerous to leave alive, or both.

This is all from one of Ian Douglas's hard sci-fi novels. Haven't read it in years, but it made me wonder why anyone would want to build superlasers.

 

Hmmm... actually I do not think spacecraft toting such powerful weaponry, mine included, is realistic... at least if going by modern science.

Because of both waste heat and weight. Getting thousands of tons into orbit is no small feat, as we struggle to get a few tons payload into orbit as it is.

Waste heat is dealt with a lot of mass, whether it's reaction mass which requires less volume, or radiators which need to be truly massive in volume.

 

So it is far more realistic for moons without atmospheres to be toting superweapons to fend off spacecraft and missiles.

Also by the time one has a constant acceleration drive and can put it on a tiny missile, warships will be virtuallty obsolete apart from merely being missile carriers to warp or jump from one solar system to the next. At that point even superweapon toting moon base could be overwhelmed if enough missiles attacked at once.

Which is why moons would need multiple bases with superweapons. Hitting targets relliably a lightsecond out.

 

Super death beam spaceraft is a unlikely as the wasteheat requirements mean you may as well build a massive spacestation instead.

Missile toting spacecraft remain the easiest space battleships one can make, as waste heat is not an issue.

Edited January 4, 2020 by Spacescifi

[wumpus]

16 hours ago, Treveli said:

(looks through his 'Superweapons of the Multiverse' cards, lays one on the table)

High-c Bucket of Sand.

Sand blasts everything. Ships, stations, planets. Trillions of kiloton-range detonations. And the only warning you get is a millisecond or two before it hits you. Cost- one freighter, few tens of thousands of tons of dirt.

Pretty sure L. E. Modesitt Jr. used this (or just the freighter) in an early work.  Easily justified assuming the character had absolute knowledge of the state of the universe via direct connection from the author, but without that would be a horrendous war crime considering the chance of "I could be wrong".

Hydrogen bombs on ICBMs already have hit the "end of the arms race", they inflict sufficient damage such that the target ceases to exist functional society and can't be effectively stopped.  The "high speed freighter" has the advantage that any attack that adds energy to it is unlikely to stop it in the least (you have to hit it very early to deflect it, much like a very real asteroid threat to Earth).

As far as "radiators for deathrays", elsewhere on this forum* I've calculated that even with unobtanium cooling systems, you'd still only get 36kW/m² out of your heat sinks (or 60MW for heatsinks the size of ISS).  I wouldn't assume any "deathrays", or if you do all combat is trying to stealthily move around (probably next to impossible) to attack from three different angles so you can saturate the heatsinks.

* my notes just say ~60MW for ISS-sized heatsink.  So  I could be wrong by a factor of 14.  21st tech might be able to get close (within half?) but the "unobtanium" requirements are *severe* and the rest is basic thermodynamics.

[Spacescifi]

11 minutes ago, wumpus said:

Pretty sure L. E. Modesitt Jr. used this (or just the freighter) in an early work.  Easily justified assuming the character had absolute knowledge of the state of the universe via direct connection from the author, but without that would be a horrendous war crime considering the chance of "I could be wrong".

Hydrogen bombs on ICBMs already have hit the "end of the arms race", they inflict sufficient damage such that the target ceases to exist functional society and can't be effectively stopped.  The "high speed freighter" has the advantage that any attack that adds energy to it is unlikely to stop it in the least (you have to hit it very early to deflect it, much like a very real asteroid threat to Earth).

As far as "radiators for deathrays", elsewhere on this forum* I've calculated that even with unobtanium cooling systems, you'd still only get 36kW/m² out of your heat sinks (or 60MW for heatsinks the size of ISS).  I wouldn't assume any "deathrays", or if you do all combat is trying to stealthily move around (probably next to impossible) to attack from three different angles so you can saturate the heatsinks.

* my notes just say ~60MW for ISS-sized heatsink.  So  I could be wrong by a factor of 14.  21st tech might be able to get close (within half?) but the "unobtanium" requirements are *severe* and the rest is basic thermodynamics.

 

 

That is why I mentioned a moon based super sand blaster weapon.

You literally have kilometers of land to conduct or even convect wasteheat to.

Result? Those battle bases have what appears to be gas billowing from them. That is not mere steam though. That is waste heat carried away by the surface of the moon's crust being turned into a gas via waste heat and shunted as gas.

 

Particle blasters beat lasers too, since even laser lenses have thermal limits, unless a plasma lens is used... which also requires similar heat rejection abilities that an airless moon could provide.

Edited January 4, 2020 by Spacescifi

[Guest]

3 hours ago, Scotius said:

We are talking about interstellar civilizations here. With entire star systems worth of materials and space accessible. At this point if you lack anything, you are either lazy or extremely unlucky. Barring the discovery of truly unique resource (coughSpicecough), waging a war for something will probably cost more than getting it from somewhere else without bloodshed.

Maybe you're just using that much. If your civilization hinges on building Dyson spheres on a regular basis (say, to produce antimatter in order to power all those interstellar engines), then a star systems' worth of materials can mean surprisingly little. Also, habitable (or even terraformable) planets can themselves be a scarce resource, if your civilization is big enough. 

1 hour ago, Okhin said:

- You're not even trying. There might be a better way to feed everyone with what you have. It can be promoting some birth control system, a more efficient diet (less meat, more fibers etc), or doing more science to improve energy efficiency conversion, which lead to a higher amount of proteins per watt invested in growing them (meaning you either spend less of those protein for the same amount of energy, or that the overhead cost of producing more energy is compensated).

Humbug. You're talking from a modern perspective. People in, say, bronze age had no idea such things were even possible. Birth control is a modern invention (barring an occasional herb). Science is a modern invention. No responsible king would bet the lives of his people on some philosopher who told him he could get more crops out of his fields by, say, planting a different one each year, because he has to work with what is, and not with what might be. And no king in history would bet the lives of his people on a "let's invite some philosophers to see if they can improve our crop yields" scheme, because it simply wasn't a thing back then. As for diet, it was already dictated by available land. Nobody (besides the Church) told the people what to eat.

FIY, "nationalism" and "communism" are also modern ideas. In fact, you seem to think that history started with French Revolution. For most of the time before that, there were only "your people" and "the other people". A king or chieftain had his people and his land, off which he had to feed them. If there were more people than the land could feed, it meant either finding new, uninhabited (and usable, either directly or by developing it somehow) land, or taking some from the other chieftain's people. Either was risky, and if you were stuck in the middle of something like Europe or Mesopotamia, the former option wasn't really on the table.

Edited January 4, 2020 by Guest

[Okhin]

Well, I cannot really dwelves into Stone age politics, because we basically knows nothing about it (there was some settlements that we did find, but that's probably hardly enough to extrapolate precisely). And I would disagree with science being a modern invention. I mean, doctor and shamans did have some kind of science thinking (in that they tried to understand the world and were able to reproduce experiments and makes assumption and hypothesis). I mean, 10 thousands yer before our epoch, there was cities being built. Which requires some level of planning and forethinking, meaning you need to understand your environment to have a city. So you have science. Not odern science as it's done today, but still science.

And even for nomadic lifestyles. There was a need to follow some path, to share data among groups of people, etc. Again, science.

Feudal Kings are a perfect example of not even trying. They considered the population has a symbol of power and a ressources they can use. They did not really care about peasants except when some of them rebelled and opposed their liege. So yeah they did not try to make a better use of the ressources they had, because all they cared about was forcing their view of social order on everyone else. And be the highest power. They even embraced religion to claim divine right and legitimacy.

But, I digress :p

And I'm still wondering if something like a Thor shot platform isn't a way more realistic and cheaper weapon than a relativistic one. You need to get close, or do your orbital math right, but it seems more efficient than trying to accelerate anything to relativistic speeds. Even for a level 2 Kardachev civilisation. I mean, when you can harvest stars, you build a stellar engine and just move your system where there's space. And if you're not yet a type 2, then relativistic weapons seems out of reach.

[kerbiloid]

48 minutes ago, Dragon01 said:

FIY, "nationalism" and "communism" are also modern ideas. In fact, you seem to think that history started with French Revolution.

The "communism" is just a form or a callname for "utopic socialism" known since anticity.
It's just "to live as a commune", just everybody treats the "commune" in his own manner.
The French Revolution (which, btw took place after the Netherlands, American, and two (?) English ones) was based on the "utopic socialism"/"communism" works of Medieval authors.

The "nationalism" is just the idea of the antic polis community (opposing the other world) extended when the community started being treated as a "nation", i.e. just moar people.

Both are just a continuation of "our tribe, and others".

54 minutes ago, Dragon01 said:

For most of the time before that, there were only "your people" and "the other people". A king or chieftain had his people and his land, off which he had to feed them.

For most of time before people lived as a tribal family, and there were no "kings" in medieval sense, only chieftains, i.e. the toughest guy in the family, and eldermen, i.e. adult ones.

Kings exist only for 3 ky of 200 ky of human prehistory, and ~10 ky of the civilization, not everywhere, and not always.
And not that they did what they wished, as there always appeared a backup king if the current one deviated too far from the society mainstream or started to redistribute resources on his wish.
Sometimes they call it law, sometimes traditions.

3 hours ago, Spacescifi said:

True but that still leaves uniquely human reasons for war that animals which fight over resources would never consider... idealogy and religion

The former two just explain why the resource redistribution is necessary or was legal.

[Guest]

1 hour ago, Okhin said:

And I'm still wondering if something like a Thor shot platform isn't a way more realistic and cheaper weapon than a relativistic one. You need to get close, or do your orbital math right, but it seems more efficient than trying to accelerate anything to relativistic speeds. Even for a level 2 Kardachev civilisation. I mean, when you can harvest stars, you build a stellar engine and just move your system where there's space. And if you're not yet a type 2, then relativistic weapons seems out of reach.

Thor had its own problems. For one, a kinetic rod doesn't strike with the weight of a strategic nuke. Far from it. The original Project Thor used huge rods that struck at about 3km/s, and you can't really get much better. The main problem is the atmosphere. Any attempt at kinetic bombardment will have a hard time with it, because drag is proportional to velocity. Hypervelocity rounds disintegrate, all others get slowed down a lot. TBH, as far as weaponry goes, nukes really are some of the most efficient weapons possible.

52 minutes ago, Okhin said:

Which requires some level of planning and forethinking, meaning you need to understand your environment to have a city. 

No, you don't. One guy builds a house. Then another builds a house next to the first guy. Then another. Then the chief of the tribe builds a castle next to the houses, because that's where everyone lives, anyway. Here's your city. If you ever tired to navigate any suitably old one, it'd become apparent this paradigm was at the heart of most city building up until very recently. Again, planned architecture is a recent invention. The closest things we had to "science" were, for a long time, philosophy and theology. Most radical innovation came from someone smart having a good, practical idea that spread around. There weren't any government-sponsored research projects (although kings would sometimes patron philosophers).

59 minutes ago, Okhin said:

Feudal Kings are a perfect example of not even trying. They considered the population has a symbol of power and a ressources they can use. They did not really care about peasants except when some of them rebelled and opposed their liege. So yeah they did not try to make a better use of the ressources they had, because all they cared about was forcing their view of social order on everyone else. And be the highest power. They even embraced religion to claim divine right and legitimacy.

Not true. Feudal kings didn't care much for peasants because they were plentiful. Like with any other good, supply exceeded demand, so the price was low. Again, no king before Enlightment thought in terms of "social order", or any other such fancy terms. Even Divine Right of Kings is a 16th century invention. Nobody needed that sort of thing most of the time. Peasants fed lords and knights, knights protected peasants and lords from raiders and other lords' knights, and lords managed peasants and commanded knights. Most of the time, it worked reasonably well for everyone involved. The lords very definitely had an incentive to get the most of their domain, since more produce meant more taxes. 

6 minutes ago, kerbiloid said:

For most of time before people lived as a tribal family, and there were no "kings" in medieval sense, only chieftains, i.e. the toughest guy in the family, and eldermen, i.e. adult ones.

They called themselves various titles in various languages, but the sense was the same. "King" is just a familiar word to use for them (and it's only about 1500 years old, coming from Charlemagne's name). 

14 minutes ago, kerbiloid said:

The "communism" is just a form or a callname for "utopic socialism" known since anticity.
It's just "to live as a commune", just everybody treats the "commune" in his own manner.
The French Revolution (which, btw took place after the Netherlands, American, and two (?) English ones) was based on the "utopic socialism"/"communism" works of Medieval authors.

The "nationalism" is just the idea of the antic polis community (opposing the other world) extended when the community started being treated as a "nation", i.e. just moar people.

Both are just a continuation of "our tribe, and others".

Yes, but calling them "communism" and "nationalism", building them shrines and so on is a modern invention. French Revolution, in particular (and especially Napoleon) codified the idea of dying for it. Before, people fought for money, out of duty, and occasionally for personal glory. 

[Spacescifi]

 

1 minute ago, Dragon01 said:

Thor had its own problems. For one, a kinetic rod doesn't strike with the weight of a strategic nuke. Far from it. The original Project Thor used huge rods that struck at about 3km/s, and you can't really get much better. The main problem is the atmosphere. Any attempt at kinetic bombardment will have a hard time with it, because drag is proportional to velocity. Hypervelocity rounds disintegrate, all others get slowed down a lot. TBH, as far as weaponry goes, nukes really are some of the most efficient weapons possible.

No, you don't. One guy builds a house. Then another builds a house next to the first guy. Then another. Then the chief of the tribe builds a castle next to the houses, because that's where everyone lives, anyway. Here's your city. If you ever tired to navigate any suitably old one, it'd become apparent this paradigm was at the heart of most city building up until very recently. Again, planned architecture is a recent invention. The closest things we had to "science" were, for a long time, philosophy and theology. Most radical innovation came from someone smart having a good, practical idea that spread around. There weren't any government-sponsored research projects (although kings would sometimes patron philosophers).

Not true. Feudal kings didn't care much for peasants because they were plentiful. Like with any other good, supply exceeded demand, so the price was low. Again, no king before Enlightment thought in terms of "social order", or any other such fancy terms. Even Divine Right of Kings is a 16th century invention. Nobody needed that sort of thing most of the time. Peasants fed lords and knights, knights protected peasants and lords from raiders and other lords' knights, and lords managed peasants and commanded knights. Most of the time, it worked reasonably well for everyone involved. The lords very definitely had an incentive to get the most of their domain, since more produce meant more taxes. 

They called themselves various titles in various languages, but the sense was the same. "King" is just a familiar word to use for them (and it's only about 1500 years old, coming from Charlemagne's name). 

Yes, but calling them "communism" and "nationalism", building them shrines and so on is a modern invention. French Revolution, in particular (and especially Napoleon) codified the idea of dying for it. Before, people fought for money, out of duty, and occasionally for personal glory. 

 

God, glory, and gold are and were the main motivators for humans living at any given time.

Fighting for profit is is related to gold or resourcrs. Fighting for God or religion is more than simply justification of taking over resources as kerbiloid thinks. In some cases it involves total genocide because of hating a certain idealogy or religion, which is not necessary even in a war setting. It's not even about taking the resources for yoyrself when you are willing to make said land unusuable in the process for years on end in the process of wiping out the populace.