Thot

On 6/3/2022 at 7:13 PM, ThornPlutonius said:

Remember to account for the medium through which/across which the vehicle is moving.  High traction?  Low traction?  Visibility? A Lamborghini will fly down a long straight smooth highway, but will relatively quickly become undrivable on soft wet uneven ground that is full of vegetation.

Hence my conclusion that the same table cannot possibly apply for all types of vehicles and my proposal to define speed ranges for each type of vehicle, say, a walker, a grav speeder, an airplane, a car, a spaceship.

How do you handle it?

Only now I found the table for vehicles in M-Space. 😄

But that doesn't make sense, does it? With that,. I could build a car breaking the speed of sound.

To explain this maybe a bit clearer.

Say, I have a car with speed stat 2 and one with speed stat 19. How would you determine what precise top speed they each have, knowing that cars can go up to 400 km/h?

And what about a car with speed 18 compared a jet airplane with speed stat 3?

And so on. In a vehicle-centric campaign, that could become rather important. Especially when using M-Space's vehicle construction system.

I think I am going with the following approach:

I define a range of movement in a given medium, say, 50-400 km/h for a four-wheeled internal combustion car. Speed stat 1 then represents the 50 km/h, while speed stat 120 defines the theoretical maximum (a hypothetical car that is only engine of the best quality).  The range between my set speed boundaries of 100 to 400 is 300, so adding one speed stat point roughly equals 3 km/h. So speed 10 would be 130 km/h, speed 20 would be 160, and speed stat 40 would be 220 km/h.

Another example: Say, I have a space ship with a fusion torch drive. Ships with that drive type usually do accelerations of 0.001 m/s² and 0.01 m/s². That means a spread of 0.0099, distributed evenly among 120 theoretically possible speed stats is about 0.000075. So a speed stat of 20 will be equivalent to roughly 0.0025 m/s² of acceleration.

But I would love to read how others have approached this? Or what do you think of the above approach?

11 hours ago, Ian Absentia said:

[...]  For instance, a common passenger car might be listed as 100/160 kph.  In fact. I might even consider increments of speed corresponding to successively higher difficulty shifts to the Drive skill, perhaps 60/100/130/150  (Standard/Hard/Formidable/Herculean). 

Also an interesting thought, in fact  I am going to steal it for my planned vehicle-centric campaign!

11 hours ago, Ian Absentia said:

Wait, but the title of the thread mentions meters per second, more or less the scale used for strategic movement on foot.  Did I miss something?

!i!

Well, kph or m/s is just a matter of computation, of course. The key is: The abstract speed stat of two different vehicles (of the same type or of different types), how do they translate to actual speeds in concrete numbers?

Obviously, vehicle speeds in Mythras and M-Space are abstract values and cannot be directly translated into an actual real-life speed value.

But as soon as I have people on foot and vehicles interact with one another, I need some kind of actual, non-abstract speed value for a given vehicle. How have you guys solved this problem in your campaigns? Have you just declared a rough range for each vehicle class (such as 100-200 km/h for cars, and 100-850 km/h for propeller-driven airplanes), and placed any given vehicles in that range according  to their speed?

7 hours ago, AndreJarosch said:

CHARAKTER-NACHBAU-WETTBEWERB

Wie wäre es, wenn jeder der ein M-SPACE zu Hause hat versucht EINEN Charakter (Humanoid, Roboter, oder Alien) einer beliebigen SciFi-Franchises [...]

 

Ich habe gerade einein Schreitpanzer (Mecha) gebaut, mit den Fahrzeugregeln. Zählt das auch? :)

I was forced by the players to use Elric, Dyvim Slorm, and Dharnizhaan (yes) as NPC's. It was a hairy thing, but I think I did them justice to some extend.

Never used any pregenerated characters in any RPG, though. Players should be able to forge their own characters.

... and nobody here is talking about this?
Elric:

https://comicbook.com/tv-shows/2019/11/19/elric-saga-tv-series-michael-moorcock/

Hawkmoon:

https://deadline.com/2019/02/bbcs-michael-moorcock-runestaff-1202556240/

On 10/29/2019 at 1:27 PM, Thot said:

I'll have to read the rest later on, but it does look promising from what I've seen already.

So... Having read it further, the idea does have merits, but somehow doesn't enthrall me to run a campaign in it.  I'd maybe use it in some kind of world hopping campaign as a stop between adventures. But for a setting fully based on this one world, it seems... too peaceful? I mean, sure, there's the Cold War with a somehow only half-communist dictatorial Soviet Union, but that doesn't really inspire me. Maybe it's using a divergence point way, way in the ancient past of the early 20th century that fails to bewitch me... but then again, it's the only that makes sense when emulating the pulp sf, "inhabited  solar system" genre.

It's pulp in all its glory. Not quite my genre, but it's well done, I enjoyed the read.

I totally forgot the existence of this until now; bought the PDF. Thanks for this thread!

Their nuclear rockets have an exhaust velocity of about "25 times that of the best chemical rockets", which would translate into roughly 111,550 m/s. This results in these delta V numbers per tenth of ship mass as fuel:

1       11,753
2       24,892
3       39,787
4       56,983
5       77,321
6       102,212
7       134,303
8       179,533
9       256,853
9.9     513,707
9.99    770,560
9.999   1,027,413

I'll have to read the rest later on, but it does look promising from what I've seen already.

7 hours ago, seneschal said:

What happened to all the adult crewmen he shipped with?  They are in their 90s or older.  Do we assume advanced medical care will keep them spry? 

Tangentially relevant: https://lifespanbook.com/

4 hours ago, seneschal said:

Good input, Joerg!  Thanks.  So how do we make these concepts a playable part of M-Space?

There are many setting-specific variables. You have to decide how much mass a solar sail will have per square km. Something like 3 grams per square meter seems realistic; that would mean 3 tons per square km. So e.g. a 30 ton ship would have 1 module for 1 km² of solar sail, providing the ship with an acceleration of  0.0003 m/s² at 1 AU distance from the sun.

There are, by the way, also concepts of solar sails that are not actual sails, but magnetic fields filled with thin hydrogen, for the same effect, but with potential of a much larger sail - if you have the energy.

4 hours ago, Joerg said:

Returning inward probably requires slingshot maneuvers around massive objects for change of direction and weaker lateral acceleration for additional tack.

You just turn the sail 45° from the star so that it slows your orbit around it, and then the star's gravity does the rest. Likewise, you can turn the sail so that your orbital speed increases.

For solar sails, the table here is also highly relevant:

https://en.wikipedia.org/wiki/Radiation_pressure#Pressures_of_absorption_and_reflection

At Earth's distance from the sun, the radiation pressure is about 9 Newton per square kilometer of solar sail surface. In other words, if you had a 100 ton ship with a solar sail 100 by 100 km, you'd be able to accelerate at roughly 1 m/s², assuming 100% efficiency of reflection.

So, you need an incredibly light material to make a solar sail worth doing, obviously.

And for a fusion rocket, with an exhaust velocity of 100,000 m/s:

1       10,536
2       22,314
3       35,667
4       51,083
5       69,315
6       91,629
7       120,397
8       160,944
9       230,259
9.9     460,517
9.99    690,776
9.999   921,034

Note, however, that this would require a reactor in the terawatt range, for any meaningful acceleration numbers.

Same numbers for an ion drive with an exhaust velocity of 30 km/s :

1       3,161
2       6,694
3       10,700
4       15,325
5       20,794
6       27,489
7       36,119
8       48,283
9       69,078
9.9     138,155
9.99    207,233
9.999   276,310

(Keep in mind, acceleration for this type of drive is way, way, way below 0.1 G, so no liftoff with this.)

I have thought a bit about the original question. So, if the "modules" in M-Space refer to mass (not volume), which would make sense, you could easily define fuel tank systems that have a certain delta V, depending on the share of fuel tank modules compared to the whole ship.

For a chemical rocket like SpaceX's new methane-oxygen drives, that would probably look a bit like this, assuming a 10-module ship (and easily scaleable from there)

1       381
2       807
3       1,289
4       1,847
5       2,506
6       3,312
7       4,352
8       5,818
9       8,324
9.9     16,648
9.99    24,972
9.999   33,295

The first number is the amount of modules reserved for fuel tanks in a 10-module vessel, the second, larger number is the delta v (the total amount of speed change the ship can carry out before refuelling) in m/s.

For reference: In order to be in an Earth orbit, you need at least 7,800 m/s of actual speed.                                                                                  

59 minutes ago, g33k said:

Once upon a time, planets as fixed objects in concentric spheres centered on the Earth was the valid, accurate model.

Nope. It was a fantasy, not a model by any standard.

59 minutes ago, g33k said:

Then people noticed that it was a little bit off...  Not to worry, though, it's just a little bit.

Actually, it was off by dimensions.

"We have made progress in the past" is a false analogy here, guys. Sure we can engineer a lot of stuff. We will eventually turn this solar system into a Dyson swarm, I have no doubt, though it may take longer than many here think. But FTL?

I am not saying FTL will not happen because I lack imagination. I am saying it because all we can OBSERVE in this universe points to the nonexistence of FTL or, in fact, interstellar travel.

4 hours ago, Joerg said:

That's assuming Malthusian population growth, a theory that doesn't quite work for civilizations.

A society (or multi-society community) that can do FTL will use all available resources eventually. Given the age of the unvierse, "eventually" would have happened already.

4 hours ago, Joerg said:

 

My point, really. Our window of observation is too short.

Our window of observation is the age of the universe. That's hardly short.

We don't see giant interstellar civilizations consuming planets. We don't see Dyson spheres or swarms. We don't see space battles. We don't observe visitors, and our planet was full of natural resources when we started mining it.

4 hours ago, Joerg said:

While you're at it, take the matter from the suns as well, and increase Hawking radiation on the event horizons of black holes, evaporating them. Such a locust civilization would be leaving a void behind. (Or something like Dark Matter.)

Exactly, and we are not observing this. So the only logical conclusion is: it is not possible. Because if it was possible, those civilizations who do it would outcompete those who don't.

4 hours ago, Joerg said:

Stuff bound in planets are the waste heaps of the universe.

When resources are used up everywhere, you start recycling waste. This isn't happening, despite the age of the universe.

4 hours ago, Joerg said:

I'm with Isaac Arthur on this - if you manage to colonize the outer system, there is nothing to stop you from continuing into the Oort Cloud, and the interstellar space beyond until you reach the next star system. You can do so at ppm of C.

You can never even get close to any speed worth  mentioning as a fraction of c.

4 hours ago, Joerg said:

Because that would be stupid. If you want heavy elements, go to mercury, or collect asteroids and meteorites. Way more bang for the energy put in.

Yet, mercury and the asteroids are still there.

4 hours ago, Joerg said:

We assume that Mercury originally came with a lithosphere. That isn't there any more. We have no idea whether all of that just evaporated or whether someone came and harvested.

We do know that. Such a group would have stripmined our asteroids and other planets, too.

4 hours ago, Joerg said:

If you talk about strip-mining our system over the course of 5 billion years, a superior civilization could have visited about 5 billion years ago to harvest the aggregation disk, and leave the rest as a waste pile.

That would be a waste (sorry for the pun).

4 hours ago, Joerg said:

Earth has nothing that you cannot get more easily elsewhere in our solar system, except for organisms which may hinder your extraction processes.

We already talked about this - not in quality, but in quantity. There is a lot of stuff on Earth, not to mention it is a free habitat.

4 hours ago, Joerg said:

Why bore deep wells and push the stuff up our considerable gravity well

But see, either our gravity well is "considerable", because technology does not allow to fly to orbit and beyond cheaply; in this case, interstellar flight is impossible. Or it is not considerable, in which case interstellar flight may be possible, but then we'd see civilizations doing it. Right in our backyard.

4 hours ago, Joerg said:

when you can just pump the liquid off Titan for a fraction of the effort?

Because someone already did that a million years ago. Or a billion.

4 hours ago, Joerg said:

My point is that if some galactic civilization came here for a mining operation in a distant past (when the sun was less glaring than today), hardly anything would have been extracted from Earth.

1. The other planets ae untouched and pristine, too.

2. When you make the journey, you take everything within reach, that's just efficiency. The whole inner system would be devoid of everything if interstellar flight was possible in this universe.

4 hours ago, Joerg said:

Strip mining on Mercury may have happened without us ever knowing about it.

(No, we'd have noticed that by now.) But why would they stop at Mercury?

4 hours ago, Joerg said:

While Germanicus went and cleared up the mass graves at Kalkriese, according to Tacitus, the Romans didn't return to settle Germania Magna after the Varus battle. Not worth the effort.

But given enough time, someone did. Wait another 20,000 years, and nothing will be left to use.

1 hour ago, Lurking Grue said:

Same here. As long as the assumptions and explanations are sufficiently logical and the universe abides by them (and not changing them on a whim with technobabble), and as long as the whole package is internally consistent, it's Good Enough (tm) for me. I basically want space opera with aspirations of hard SF without being utterly slaved to hard science.

And that's a reasonable thing to play and tell stories in. It is great fun, after all!

But sometimes I want to make a proper prognosis, and the result is : We'll use chemical rockets for large-scale space faring, and that is likely the best solution, all things considered.

2 hours ago, seneschal said:

Humans have an annoying tendency to turn their elves and dwarves fantasies into realities, by risk and recklessness if not by smarts and science.

Humans are creative users of natural laws, not changers of natural laws.

3 hours ago, Joerg said:

This is what people said about flying or sailing past the horizon, too...

No, they didn't. Many people said it was theoretically possible, it was just supposed to be too difficult engineering.

3 hours ago, Joerg said:

Why would there have to be an alien colony on our planet to prove past visits?

There would be a colony (we would BE a colony) because the whole universe would be teeming with their colonies, nd there would simply be no matter left not used by their civilization(s). Billions of years of time!

Do a little compuation on how long we would need to settle the galaxy with 0.1c ships and a propulation growth rate of 2%. That's 400 billion stars. Please, do it. It's insightful.

3 hours ago, Joerg said:

Quantum gravity is not really resolved, is it?

Details. We know how gravity works and that matter causes gravity. Quantum gravity would just be a more detailed model that is reconciled with other models for other areas of physics.

3 hours ago, Joerg said:

Moving through interstellar space is a boring case of millennia of "are we there yet" with the slight problem of remaining alive and goal-oriented during that journey.

Not just a few millennia. Millions of years.

3 hours ago, Joerg said:

Why settle here? Just because we have adapted for this, our planet's circadian cycles and surface gravity might be deleterious to the visitors, our biosphere too aggressive, and our atmosphere toxic or at least noxious to the explorers taking a look at our rock with their interstellar probes.

Sure. But why would such a civilization settle on planets?

At the very least, to exploit the planets' resources. Break them up and consume them. But we'd have noticed if that had happened.

3 hours ago, Joerg said:

Look at the projections made by SF authors like Jules Vernes and his contemporaries. Those were made by extrapolating their cutting edge technology and society into the future.

But that is what I am doing. I am extrapolating, and the result is: Sorry guys, no FTL, no interstellar flight, but a solar system teeming with life.

3 hours ago, Joerg said:

Plus, do we have clear evidence that the introduction of cyanobacteria to our biosphere was not an invasive species?

We do have evidence that no alien intelligent life has stripmined our planet.

3 hours ago, Joerg said:

There was a rather recent paper (a year or two ago) that tackled the problem that traces of a technological civilization prior to the Chixculub impact would be very hard. Even ceramics have a very hard time surviving such time-spans.

Sure, that is possible. I like to use that notion, too. Keep in ind, though, that we have found an awful lot of fossil fuels... which a prior civilization would likely have used.

3 hours ago, Joerg said:

So what resources does our planet offer that you couldn't get out of the Jupiter or Saturn system or lift off Mercury with less interference and trouble? What exactly makes our dirtball prime estate for a space-faring civilization?

Our planet doesn't offer anything different from there, but more of it. Growth is exponential and needs EVERYTHING. If you can get it.

6 hours ago, Joerg said:

We haven't gotten much closer to understanding gravity and whether there is a quantum "particle" describing the exchange.

The thing is, we have. It's just a lot more boring than we had hoped.

6 hours ago, Joerg said:

Also, there have been assumptions about physical limitations that have been overcome by engineering,

But it's not an assumption.  See, even if Special Relativity's axiom  of light speed being an ultimate upper limit turns out to be wrong, the amount of energy required to get even close to that speed is forbiddingly high. I mean, really, really forbiddingly high.

6 hours ago, Joerg said:

Within memory of our culture, which is at most 12,000 of our planet's rotations around the sun.

Why would aliens leave? And why would then not another civilization come, settle and stay?

At least one of the many civilizations that must exist in our universe would feel the need to grow and spread out. That one would grow exponentially, eventually settling every known place in the universe (not just our galaxy). And that would have happened millions of years ago already - which means we'd already be a part of it.

We have not been visited, otherwise we'd simply know from direct, on-planet evidence that interstellar travel is possible. The answer to Fermi's paradox is not a great filter, but the simple fact that interstellar distances are just too large to overcome.

6 hours ago, Joerg said:

And the planet might be a protected biodiversity habitat, or rather might have been one prior to our efforts during the last few centuries. When the park rangers return, they might be angry about the squatters.

The notion of an interstellar embargo of any kind only works when there is FTL. Without it, how are you going to enforce it?

But even in protected parks, there are violations of that protection status from time to time.  By now, we would have noticed.

6 hours ago, Joerg said:

Assuming that it takes sublight speeds to travel from star to star, would you send such an expedition lasting centuries to watch primates fling their feces at one another?

I would simply not care for the local animals (and animals some interstellar civilizations would deem us, and treat us accordingly). I'd just do what we humans always do: Take what's theirs and be rich with it. And we humans do that because it is the optimal strategy to spread our genes, which is what we (and any other lifeform conceivable) are evolved to do. This would not differ with aliens.

10 hours ago, g33k said:

I tend to feel that we literally do not know what is possible and what is not.

Even if we are not sure about our own physics, we can deduce from the fact that there is no alien colony on this planet.

Quote

And science fiction doesn't really care; everybody has their own hard-vs-soft thresholds for their sci-fi.   😁

Sure, I do FTL SF myself from time to time, have even written a novel or two with it. But let's not kid ourselves: Those are no less fantasy than stories with elves, dwarves and orcs.