System for a zero-combat dungeon crawl?

[Trekkin]

Theoretically possible if you elide the requirement for negative energy density and negative mass, perhaps, and feasible if you allow for your ships to store literal tons of antimatter. We have no idea how to do any of that at the requisite scale, which is why all the popular articles about "warp drive" start with Star Trek references and never get any deeper from there. It's a blatantly aphysical black box.

This is, I feel, a massive problem in the context of a roleplaying game, because as soon as the PCs shoot through or melt the warp drive -- and in my experience this is inevitable -- we're back to making up magic for the sake of the story. Wormhole FTL at least has the advantage that a sufficiently perturbed wormhole can plausibly collapse into a singularity and thus be kept safely away from prying eyes, and a wormhole terminus is a superficially physical object that the PCs can chuck around.

And yes, I'm working on a system that's mostly concerned with encumbrance and skills. I'd have used Torchbearer's slot approach, but it feels wrong to limit the amount of mass/volume that can be moved in microgravity instead of it simply becoming continually harder to move and more expensive in terms of propellant as mass increases.

[CharonsHelper]

Theoretically possible if you elide the requirement for negative energy density and negative mass, perhaps, and feasible if you allow for your ships to store literal tons of antimatter. We have no idea how to do any of that at the requisite scale, which is why all the popular articles about "warp drive" start with Star Trek references and never get any deeper from there. It's a blatantly aphysical black box.

The first article I linked especially DOES go into somewhat more depth.

And of COURSE they start with Star Trek references. That's the hook.

And where the heck was antimatter even referenced? (Not that I'm anything like a physicist.)

[Trekkin]

I did read the space.com article. Quite apart from it being critically wrong, I see only details, not depth. The article is completely devoid of mathematics, with the closest we get being a prosaic description of the energy requirements of a flat ring of aphysical matter versus a torus of aphysical matter. The one is the "mass-energy" of Jupiter, while the other is the mass of Voyager. Those aren't numbers, though. (It also calls the above energy requirement "the only problem" with warp drive. If only.) The rest of the article is built on interviews with Drs. Harold White and Richard Obousy, again with no mathematics in sight. (There's also no discussion of the impossibility of steering/stopping the field or surviving the heat dumped into the flat region by Hawking radiation, but I can forgive that.)

That isn't an understanding of how warp drive works in any manipulable sense; there's no reasoning behind any of the figures. Had I come into that article with no knowledge of the metric Alcubierre described, I would have left with none -- and so, if I were to put "Alcubierre drives" into my game, I would be reduced to making stuff up as soon as a player, say, rammed something at FTL speeds or kicked somebody out the back of the ship or whatever.

As for antimatter, when they talk about "mass energy", they mean "mass-energy equivalence", a reflection of the fact that energy and mass interconvert at a ratio described by Einstein's most famous equation. Listed in mass, it's also how much matter and antimatter you need to annihilate in a perfectly (impossibly) efficient reactor to get a given quantity of energy -- and, given the Voyagers' current 700 kg mass, it seems more relevant to quote the required energy as 700 kg of matter-antimatter instead of, say, four petagrams of dry camel dung. ("Literal tons" was my first-order approximation of the actual amount needed given a less than perfectly efficient reactor.)

[daniel_ream]

The devil, in this case, is not in the details; it's fairly easily demonstrable mathematically that if you can travel faster than light by any means, you can violate causality and create an unresolvable paradox. That's the problem with FTL.

Wormholes sidestep this by connecting two locations in space-time rather than two locations in space, which is why current hard SF writers use them. But they're still something of a handwave.

[Cluedrew]

Anything beyond Mars (which they are building a spaceship to travel to) is going to involve some hand-wave... because we don't have it working. Although there is a matter of plausibility. For me the more plausible methods of faster than light travel are teleportation. Not wizard teleportation of course, probably something more complex. Say using gravity (which apparently can out pace light because it doesn't actually travel, not sure) to transmit information about something's physical configuration and then reconstruct it at the destination sight at 0.00001:0.00001 scale.

Still all sorts of problems with it of course, many in areas of study I have only scratched, but it sounds better than just going faster than physics seems to say we can.

[CharonsHelper]

The devil, in this case, is not in the details; it's fairly easily demonstrable mathematically that if you can travel faster than light by any means, you can violate causality and create an unresolvable paradox. That's the problem with FTL.

Wormholes sidestep this by connecting two locations in space-time rather than two locations in space, which is why current hard SF writers use them. But they're still something of a handwave.

Actually - warp also sidesteps FTL issues - because the ship itself isn't actually traveling FTL. It's instead warping the space around it, thinning the space in front and directing it around the ship to thicken behind (in very simplistic terms) so that it's traveling FTL in comparison to the rest of the universe, but it doesn't have to deal with relativistic issues.

I believe that it wasn't proven even theoretically possible until the 90's, and until a few years ago they thought it would take so much energy as to be useless. (not that that puts them any closer to actually DOING it)

I did read the space.com article. Quite apart from it being critically wrong, I see only details, not depth.

Well... yeah. They're pop science articles designed for people like me who don't want to wade through all of the proofs which I probably couldn't decipher anyway.

I haven't taken physics since high school, or pure math since my freshman year of high school - and I only remember a smattering of either. Even if I could wade through the proofs - I don't want to.

It's just a summary of "look at this neat science thing".

[daniel_ream]

[...] it's traveling FTL in comparison to the rest of the universe

That's the problem. If you can transmit information from one point to another faster than light can travel the intervening distance, it doesn't matter what the method is. It's fairly simple to set up a situation where you can violate causality as a result, and then the universe falls apart.

Unless Einstein is wrong, but if you're going to postulate that you're into Clarke's Third Law territory.

[Trekkin]

Actually - warp also sidesteps FTL issues - because the ship itself isn't actually traveling FTL. It's instead warping the space around it, thinning the space in front and directing it around the ship to thicken behind (in very simplistic terms) so that it's traveling FTL in comparison to the rest of the universe, but it doesn't have to deal with relativistic issues.

Those issues are separate from the causality violation daniel_ream mentioned, which allows an FTL ship to travel such that it can leave its own future light cone and thus do things like see the receipt of a message before it's sent. Make a set of Minkowski diagrams for an FTL ship travelling between two planets moving away from each other subluminally and exchanging lightspeed messages and you'll see what I mean.

EDIT: As daniel_ream explained above. Sorry!

It's just a summary of "look at this neat science thing".

Yes, it is; I don't like articles like that, but that's beside the point. My point was that such summaries aren't deep enough to be useful for worldbuilding, at least not the way I do it. "Look at this neat science thing" is fine if you know a priori that nobody is going to want to take it off the shelf and play with it. To extend the metaphor, I fully expect my players to pull it apart, run it backwards, light it on fire and whatever else they can come up with. They're not actively intent on sabotage, just curious and scientifically literate.

What I consider "hard science fiction", in this context, hides all the blatantly aphysical bits well enough that we're unlikely to run into them in-game and runs everything else with perfect fidelity to phyiscal laws at the smallest resolution my players are likely to casually calculate. Hiding the magic in unsolved problems works for a time, but dates the work; by contrast, sticking them far away causally and behind closed and spiky doors at least lengthens the amount of time before we drive merrily off the cutting edge of theoretical physics.

So yeah, I haven't found any hard science fiction RPGs.

[Psikerlord]

Having bought and read Torchbearer, I can see how its engine needs at least some conflict to drive it. It's certainly going on my list, though.

As far as what I want out of the system on the micro- and macro- levels: On the macro scale, I'd like an essentially economic motivation. The party either extracts enough loot to buy food and supplies, or they starve. See, my group likes coming up with creative solutions to short-circuit puzzles, and I'd like to tacitly encourage that in some cases while making it impractical to blow through all the walls and bridge over the all gaps and never engage with the actual puzzles.

The other half of that is limiting how long they can stay in the dungeon on any given trip. Limiting the food and water they can carry could work for that, as could putting the dungeon underwater or in vacuum. The point is to limit the amount of time they can spend inside, and thus the number of tries they have to solve the puzzles.

Thus, the basic source of tension is the knowledge that every shot at opening more of the dungeon costs them consumables, so if they fail too consistently they're going to lose the ability to keep trying (and, you know, die.) Further, it's possible that not all the doors they open stay open forever, so if they take too many risks, one relocking door could mean they're all going to die of thirst. Of course, if they don't take enough risks, they can't afford water in the first place, and if they fail the wrong puzzle they might just die outright.

So, using that to inform my choice of system:

1. I don't really need a model for physical trauma more detailed than "fine", "not fine", and "dead", although I could make good use of disease rules.
2. Some easy way of tracking consumables would be nice. I probably don't need anything more than a line of boxes for food and water though.
3. Characters can just be sets of skills, gear lists, and statuses.

I don't need skills to pertinent to the individual challenges, since yes, the players will get more fun out of solving them themselves. I could see some role for languages and an equivalent to Knowledge skills, though, for doing things like reading the warning labels on doors and recognizing esoteric cultural references.

Having actually typed that, it occurs to me that I could just track time (in and out of the dungeon) spent amassing knowledge bases and use that for skills. The more you, say, decipher ancient Precursor runes, the more quickly and thoroughly you can do so -- which, of course, biases the party towards some doors more than others and emphasizes specific understandings of what happened to the dungeon.

For fine/not fine/dead you might simply implement a 3 hit tier system, similar to D&D bloodied or not, but with an extra tier?

For easy equipment tracking - how about Black Hack's usage die rule (I think it comes from there). It goes something like when you use a thing roll a d12, on a 1or 2, next time roll a d10, and so on until d4, then whatever it is runs out.

For characters perhaps borrow the 5e skill list and gear section. Or really you could borrow this from anywhere. There's no doubt better gear books out there to throw at your players.

[Psikerlord]

I use Lamentations of the Flame Princess. Neither the system nor my games are designed as zero-combat, but individual sessions do end up like that frequently.

LotFP has the benefits of having a nifty encumberance system and being rules light. It has quick, easy to resolve rules for common activities like searching, checking architechture, digging, forcing open doors, figuring out dead languages etc. and supplies such as food, water and lamps are easy to track.

Interesting - how does LotfP deal with those common activities?

[CharonsHelper]

That's the problem. If you can transmit information from one point to another faster than light can travel the intervening distance, it doesn't matter what the method is. It's fairly simple to set up a situation where you can violate causality as a result, and then the universe falls apart.

Unless Einstein is wrong, but if you're going to postulate that you're into Clarke's Third Law territory.

Maybe I'm missing something - but I fail to see how this is more of an issue than a jet going faster than the speed of sound and arriving before it's noise arrives.

And no - it doesn't violate relativity. Relativity never says that stuff can't travel faster than the speed of light through the universe. Quite the opposite. It says that nothing can travel through SPACE faster than the speed of light. It's already been proven that light sometimes travels marginally faster than the speed of light when it's affected by gravity - because the gravity itself warps space-time.

[daniel_ream]

Maybe I'm missing something - but I fail to see how this is more of an issue than a jet going faster than the speed of sound and arriving before it's noise arrives.

Yes. Yes, you do.

And no - it doesn't violate relativity.

Learn to read.

I haven't taken physics since high school, or pure math since my freshman year of high school - and I only remember a smattering of either.

This.

[Cluedrew]

Unless Einstein is wrong, but if you're going to postulate that you're into Clarke's Third Law territory.

Didn't they have already prove that Einstein was wrong? Maybe not in this area but I'm pretty sure the who reason we have special relativity is because Einstein's general relativity didn't hold in small cases and quantum physics came out of that. And to quote the man himself:

"If an old and learned man tells you something is possible, he is almost certainly correct. If an old and learned man tells you something is impossible, he is almost certainly wrong." Maybe Einstein, lots of things get misattributed to him.

Swordsaged, I would actually like to see an answer to the question about how that violates casualty. Forget the supersonic jet, I don't see how it differs from rolling a ball down a hill and running down to catch it. (Other than the speeds involved of course.) Could we get more information on that?

[CharonsHelper]

Learn to read.

My physics in shaky - but my reading comprehension is fine.

But general relativity offers a possible escape from this constraint: through the malleability of spacetime itself. We might be unable to travel through space itself at speeds greater than 299,792,458 m/s, but if we can lessen the actual distances between two locations (or events), then not only could we travel there very quickly from the crew's perspective, but from the perspective of observers at both the source and the destination... For one, we could ship anything -- from goods to resources to people -- across arbitrarily large distances in arbitrarily small amounts of time. Messages could be delivered of upcoming catastrophes before a light signal could ever arrive, and violating our traditional notions of causality would become a routine game. But most importantly, the development of this technology would mean that humans alive at the time of development would be able to travel across the galaxy, experiencing other stars, other planets, and, if we're lucky, other civilizations.

[Trekkin]

For fine/not fine/dead you might simply implement a 3 hit tier system, similar to D&D bloodied or not, but with an extra tier?

For easy equipment tracking - how about Black Hack's usage die rule (I think it comes from there). It goes something like when you use a thing roll a d12, on a 1or 2, next time roll a d10, and so on until d4, then whatever it is runs out.

For characters perhaps borrow the 5e skill list and gear section. Or really you could borrow this from anywhere. There's no doubt better gear books out there to throw at your players.

That's a pretty good approach to injury.

As for equipment tracking, one thing I'm working on is a coarse-grained integration of the Tsiolkovsky rocket equation to calculate the propellant costs of recovering from mistimed jumps, which means I need them to track real mass. I'm almost certainly going to use a variant on usage dice for tool wear, though.

And yeah, I might start with the 5e skill section and modernize it. A lot.

[Beneath]

Basically the reason you can violate causality w/ faster than light is because for things only reachable by faster than light, sequence is undefined (relativity of simultaneity); in other words, if the distance between event A and event B is greater than c times the time between them in any reference frame, then (it is in all reference frames and) an inertial reference frame traveling at a velocity less than c exists where event A happens first, event B happens first, and they happen simultaneously (this is called "spacelike separation" because there is no reference frame where they happen at the same place; the opposite, timelike separation, has a defined sequence but in some reference frame they happen at the same place. the cusp between the two is lightlike separation, where the distance is exactly ct).

From this you can get that if you have a faster-than-light drive that does not have a preferred reference frame (i.e. whatever speed it sends you at, you can go at that speed in any arbitrary reference frame), you can take a round trip and arrive before you left.

A simple way to imagine this in two dimensions, let's use x for space and y for time in ground control's reference frame. Your ship points in some direction within 45 degrees of the y axis (the further off the axis it points, the faster it's moving), and you have an FTL drive that travels vast distances in an instant, in ship time (arrival and departure are simultaneous in the ship's reference frame). Your reference frame's "simultaneous" is the line perpendicular to the way your ship is pointing (remember, your FTL drive works on ship time, not ground control time). The math isn't exactly right here because in some cases you need a skew operation where I'm using a rotation but the principle works out.

Thus you accelerate to a high velocity, teleport to a nearby black hole, fall into a parabolic orbit, reverse your direction, and teleport back. Do this right, and you can arrive before you left. Seeing your doppleganger, you then arm and launch torpedos, shooting them down so that they can't then go back in time and murder your past self.

Did you complete the trip and shoot down your past self before you left, or were you shot down before you left, preventing you from shooting yourself down and thereby freeing you to complete the trip? Relativity does not hand you alternate timelines to play with; everything happens in one universe.

This is one of the points where relativity is weird and unintuitive, because it relies on relativity of simultaneity which is completely outside our everyday experience (in everyday life, speeds are slow enough that relativistic effects are negligible and we can sort-of assume a preferred reference frame); there's a good wikipedia article on that

Closed timelike curves become theoretically possible whenever you allow for spacelike travel, but it may be possible that you can't get any with a specific arrangement of a finite number of distinct wormholes (you can make a closed timelike curve with one, but if you're trying to get rid of them you probably can. If nothing else, you can all make them totally coincidentally more or less follow a preferred reference frame). Even the quoted article says that if you get FTL you get causality violations.

[Nupo]

I've had this idea for a while now -- and I cannot be the only one -- to run a dungeon crawl with no combat whatsoever. Just traps, puzzles, and a mystery story told through the architecture and maybe the notes scrawled on the walls.

Nope you are not the first to think of doing this. Gary Gygax himself thought of it back in 1975 when he wrote "Tomb of Horrors." Yes there is some combat in it, but not much. It's mostly traps and puzzles.

[Cluedrew]

That is an unfortunate coincidence. Just from some other stories involving the Tomb of Horrors.