Problem of math

[Rhun]

If you want to place interstellar travel out of reach, have you considered to place an "unsurmountable barrier" around the system? Perhaps the system is orbited by a thick shell of debris that just cannot be navigated. Only if you had a FTL drive you could circumvent the debris entirely. A favorite of sci-fi writers would be a semi-permanent local hyperspace "storm" that unpredictably strikes through into the normal space, making interstellar travel an uncalculable risk. Only within a certain radius around the star is the space-time continuum stable enough to normally be safe from the storm. Normally. Perhaps there are some FTL-capable ships stationed in the general area of the system, commanded by an AI acting on out-of-date orders to "quarantine" the system?

Shatterzone! (I think I still have the boxed set sitting around my house somewhere.)

 

[WayneLigon]

Perhaps I should consider travel time for 50 AUs and not worry so much about the 100,000 and consider placing a Kuiper like belt within the system, though that kinda of restricts some of the campaign ideas it does not take out the whole campaign.

The understanding that this is a Firefly like campaign is indeed true. I have wanted to run this campaign sense the early to mid ‘90s, when Firefly came out I really wanted to do it and it changed a lot of what I was thinking, but for the most part its still a space smugglers/mercenaries campaign that takes place in a solar system not of our own (not Sol).

If you want a Firefly-style campaign, don't bother with the math Honestly. Just decide how many planets you want, then make up a grid that tell how far, in days, each is from the other.

Use the gravity drive that Firefly uses. Inside an atmosphere you can only go so fast anyway before control becomes an issue, anyway, so say that it limits you to Mach 10. Outside the atmosphere you can really cut loose. With the travel times you want, you technically have a drive capable of going interstellar but the catch is that the drive only performs at all when it's within the gravity well of a star - it only works out to, say, 1 ly from the primary.

With a solar system as big as you want, you probably have more than one star in that 'system'. It's a complex arrangement but it can work (the Alpha Centauri system is set up kinda this way if I remember correctly; multiple stars within a lightyear or so of each other). The stars are juuuust close enough for the Firefly Drive to bridge that gap and do it in X days. We'll make it eaven friendlier so that tons of people would have wanted to settle here.

This way, also, you can have multiple planets inside the habitable zone (you can grow and shrink the habitable zone slightly by varying the spectrum of the star). Most of the planets in the Firefly 'verse are (marginally) terraformed moons if I remember correctly, so you can have multiple habitable moons orbiting, say, a couple of close-in gas giants. With three stars orbiting each other around a lightyear from each other, each with it's own planetary system, that gives you something like nine habitable worlds (in the venus, earth, mars bands; lets assume that Bode's Law really is one) at worst; more if you put in one or more close-in gas giants and terraform some of the moons (some might not have needed terratorming).

They used to think that gas giants wouldn't exist much closer to a star than Jupiter does or else the gas would boil off into space. I'm pretty sure we've discovered otherwise. We've also discovered supermassive gas giants orbiting other stars; it was once thought that a gas giant couldn't get much more massive than Jupiter or else it would ignite into it's own star. Apparently that's not quite true, either.

With the triple star arrangement in a triangle, you could also have a gravitational 'dead zone' in the space between them; a 'sargasso sea of space' where all the rogue bits of material and dust and such collect; there could even be room for a dark frozen 'rogue planet' in there. Perfect for a pirate or Reaver base, or area to hide from The Authorities.

 

[Rhun]

With the triple star arrangement in a triangle, you could also have a gravitational 'dead zone' in the space between them; a 'sargasso sea of space' where all the rogue bits of material and dust and such collect; there could even be room for a dark frozen 'rogue planet' in there. Perfect for a pirate or Reaver base, or area to hide from The Authorities.

A triangle arrangment of stars like this isn't possible. Taking the Aplha Centauri example, you have two stars (Alpha Centauri A and Alpha Centauri B) that orbit one another, and a third star (Proxima Centauri) which orbits the binary system much further out (approximately 0.2 Light Years in the case of the Centauri system).

 

[Pbartender]

With the triple star arrangement in a triangle, you could also have a gravitational 'dead zone' in the space between them; a 'sargasso sea of space' where all the rogue bits of material and dust and such collect; there could even be room for a dark frozen 'rogue planet' in there. Perfect for a pirate or Reaver base, or area to hide from The Authorities.

Actually, any two bodies can have such zones. They are called Lagrange points. There currently significant accumulations of asteroids in the Sun–Jupiter, Sun–Saturn, Sun–Mars, and Sun-Neptune Lagrange points.

You could still have Lagrange points between the stars in the Centauri system, but they'd be just a little more complicated, due to the distances and masses involved.


The Centauri trinary system, incidentally, is a great example of what you're looking for, Harmon. Read this essay. They don't get closer than 11 AUs, and never farther than 35 AUs. The two primarirs both have enough stable orbits to contain a few planets, and they are both sufficiently sun-like to host earth-like planets within those orbits.

Proxima is about 13,000 AUs away from the primaries, and is a red dwarf, so hospitable planets are unlikely, though there could be asteroids, moons and planets on which you could plant an enclosed colony or station.

Using very fast sub-light speeds, travel between Alpha Cen A and Alpha Cen B planets would take days or weeks. Travel to Proxima from there would take weeks or months. Travel back to earth would take years.

Alpha A and Alpha B are the "civilized" frontier colonies. Proxima can be a pirate haven, a military outpost, a mining colony, a prison station, a colony of outcast dissidents, or any combination of those. Earth hasn't been heard from in decades.

 

[Rhun]

Actually, any two bodies can have such zones. They are called Lagrange points. There currently significant accumulations of asteroids in the Sun–Jupiter, Sun–Saturn, Sun–Mars, and Sun-Neptune Lagrange points.

And to add a science fiction example of the type of thing you could find in a Lagrange Point:

The ringworld Halo from the Halo video game is located in the Lagrange Point between the gas giant (Threshold) and one of its moons (Basis).

 

[werk]

Take a note from Dragonstar...

 

[Umbran]

Actually, any two bodies can have such zones. They are called Lagrange points. There currently significant accumulations of asteroids in the Sun–Jupiter, Sun–Saturn, Sun–Mars, and Sun-Neptune Lagrange points.

Yes, but note a couple of things -

1)While Lagrage points are stable, the "three stars co-orbiting a common center of mass, with a Sargasso Sea in the center" is not.

2)The Lagrange solution requires that the objects in the third point be very small compared to the major objects. So, you can get some asteroids in the Sun-Jupiter Largange point. But you can't get the Earth in place of the asteroids there. That would not be stable.

 

[Pbartender]

1)While Lagrage points are stable, the "three stars co-orbiting a common center of mass, with a Sargasso Sea in the center" is not.

Agreed.

Though in the case of the Centauri Trinary (two close-orbiting stars and one distant-orbiting star), you simply end up with two sets of Lagrange points... one set for the close-orbiting pair, and one set for the distant star with the barycenter of the close-orbiting pair.

But yes, a simple triangle of stars with the Sargasso space in the middle is a bit far-fetched.

2)The Lagrange solution requires that the objects in the third point be very small compared to the major objects. So, you can get some asteroids in the Sun-Jupiter Largange point. But you can't get the Earth in place of the asteroids there. That would not be stable.

Good point. Though very small compared to two main sequence stars could very well include small planets and moons. But even so, even a small asteroid or asteroid field is always good fodder for a pirate base, a free port, a mining operation, a secret military base, or similar backwater "leave us alone" set piece.

 

[Aaron L]

Ever seen Cowboy Bebop? Big rings orbiting planets that a ship can fly through which take the ship to another ring somewhere else in the solar system. Kind of like some of the Stargates in Stargate: Atlantis, only much larger. That way they can go to various places in the solar system, but they can't leave the solar system becuase there are no gate ending points out there.

Well, I was all prepared to offer this suggestion, and I find out that ThirdWizard has already done the work for me


In other words: What He Said.

 

[Umbran]

Though in the case of the Centauri Trinary (two close-orbiting stars and one distant-orbiting star), you simply end up with two sets of Lagrange points... one set for the close-orbiting pair, and one set for the distant star with the barycenter of the close-orbiting pair.

I would have to go back and look at the math - I don't think you get stable Lagrange points if the two major objects are of comaprable mass. If I recall corectly, you need the situation where one object is pretty clearly orbiting another, rather than two similar-mass objects in orbit around a common center.

Mind you, you can still get that with commonly available stars - a blue giant and a red dwarf pair could produce the effect of having a couple planets and a star all sharing the same orbit.

So, in the above situation - Alpha Centauri A and B won't have stable Lagrange points. But Proxima Centauri might...