regina in-system travel

[EDG]

I don't think the presence of a significant atmosphere is a problem for a moon of a gas giant - witness Titan.

...which skirts the edge of Saturn's magnetosphere and so doesn't get bombarded by high energy particles.

Witness Ganymede and Callisto, which are big enough to have atmospheres but don't because they're deep in Jupiter's magnetosphere.

As EDG points out, the big problem is being tidally locked. It's possible that Regina has been recently captured by Assiniboia which would give a reason that its not locked, but that wouldn't help it's habitability any, as I doubt being yanked out of your original orbit does much for your habitability.

Capture is a very unlikely scenario. GG's don't just pluck planets out of their orbits .

move it further away, which I think would reduce the tidal forces and make it less likely to be tidally locked.

A moon that big will be tidelocked in pretty much any orbit. So making the orbit bigger would just make the day even longer.

 

[GypsyComet]

Is it possible that Regina is spinning again after being tidally locked? Assiniboia is missing several moons, so we know Grandfather has tinkered...

 

[EDG]

Is it possible that Regina is spinning again after being tidally locked? Assiniboia is missing several moons, so we know Grandfather has tinkered...

Nope. Not without a massive impact that would destroy all life on the moon.

Assiniboia isn't missing any moons as far as I'm aware (there's planets missing from the SM sector, but that's it). But I'm dead against invoking Grandfather, because then we may as well throw all pretence of realism out of the window since he can supposedly magically do anything.

And it's not like it would have been habitable when the Ancients first found it anyway, because it would have been tidelocked for about three billion years beforehand.

I realise that Regina is one of Traveller's "sacred cows", but there's not much anyone can do with this one.

 

[Rikki Tikki Traveller]

So, NOW you are worried about the science??!!!??!!!

Just kidding.

The Regina system makes no sense from what we know of planetary science today (or even back in the 80s when they gave it to us). There is also just about no way that the primary will have a red dwarf star in a close orbit. That combination is exceedingly rare, if it exists at all in our part of the galaxy (it MIGHT, so I won't say it is impossible, but it is basically impossible).

GG moons are going to be no bigger than Titan or Triton unless you have a superJovian or Brown Dwarf. Even then, it won't be very habitable since it will be tidally locked to the planet.

BUT, it is canon, so what can you do? Change it for your game or live with it for official sources.

 

[alex_greene]

Assiniboia isn't missing any moons as far as I'm aware (there's planets missing from the SM sector, but that's it). But I'm dead against invoking Grandfather, because then we may as well throw all pretence of realism out of the window since he can supposedly magically do anything.

If that includes pinching off whole pocket universes, moving planets into perfect Kemplerer rosettes and - allegedly - making ringworlds out of crustal material stolen from Nirton and possibly other worlds, I suppose the answer here is "Yes, he can."

However, I suspect even Grandfather might declare his innocence in the Regina matter. Current exoplanetology is turning up worlds around systems that simply could not be, according to our current knowledge of how solar systems form.

Wonder if this whole mess will be covered in the forthcoming world builder book Mongoose proposed?

 

[EDG]

Wonder if this whole mess will be covered in the forthcoming world builder book Mongoose proposed?

Depends who they get to write it (it won't be me), and whether they can keep the factual inaccuracies (as opposed to educated guesses) to a minimum.

Either way it doesn't fix the fact that most of the OTU is actually broken from a science standpoint.

 

[alex_greene]

Wonder if this whole mess will be covered in the forthcoming world builder book Mongoose proposed?

Depends who they get to write it (it won't be me), and whether they can keep the factual inaccuracies (as opposed to educated guesses) to a minimum.

Either way it doesn't fix the fact that most of the OTU is actually broken from a science standpoint.

The whole universe is actually broken from a science standpoint. It's when we rev up the science that we can see how it all in fact fits together in a way we hadn't imagined it could.

That's if we have sufficient imagination to rev up the science in the right way.

Wash: Psychic, though? That sounds like something out of science fiction.
Zoe: We live in a spaceship, dear.
Wash: So?

 

[EDG]

The whole universe is actually broken from a science standpoint. It's when we rev up the science that we can see how it all in fact fits together in a way we hadn't imagined it could.

Well, in the case of Traveller, it's because the actual world design rules for the game were broken and/or poorly researched. I'd rather not get into the whys and wherefores about how science works - our understanding may be incomplete in places, but it's not broken.

 

[GypsyComet]

Is it possible that Regina is spinning again after being tidally locked? Assiniboia is missing several moons, so we know Grandfather has tinkered...

Nope. Not without a massive impact that would destroy all life on the moon.

Assiniboia isn't missing any moons as far as I'm aware (there's planets missing from the SM sector, but that's it). But I'm dead against invoking Grandfather, because then we may as well throw all pretence of realism out of the window since he can supposedly magically do anything.

Ah right. It isn't Assiniboia that's missing moons, but rather the Regina system that's missing a gas giant... ("Grandfather's Worlds", Challenge 27)

 

[Cleon the Mad]

I have no idea if this is true of course, but I always did wonder if someone at GDW when they wrote up the Regina system had just watched Star Wars (The original film) and was thinking "Hey, Yavin IV is kind of a neat planet...moon orbiting a gas giant..why not make a major world in the Spinward Marches like it..except..hey, we'll make it a "rich" planet too, so it's not only orbiting a gas giant but it's a really nice place to live!".

Hey, just a silly thought. Sorry for the slight derailment.

 

[alex_greene]

GDW launched Traveller in 1977.

Star Wars came out in 1977.

Actually, now I come to think about it, so did 2000AD.

1977 seems to have been a good year for Science Fiction.

So it is a distinct possibility that Regina was indeed in some way inspired by the Rebel base on Yavin IV scenario.

 

[EDG]

There is also just about no way that the primary will have a red dwarf star in a close orbit.

It's worse than that - it's a WHITE dwarf. Which means it had to be a red giant at some point, which means it had to be several AU in radius (and so it couldn't be in a close orbit around Lusor), and all the planets in the system would be toast as a result.

This is why I changed Speck into a Hot Jupiter (I think actually Daryen came up with that idea in the original discussion) - this has the additional advantage of being something we often see in real systems, so there's no reason why ALL of those existing close WD companions in the OTU can't be replaced by Hot Jupiters. (IIRC Guaran is another one with a close WD, so realistically the Hivers shouldn't exist... unless it's removed or replaced with a Hot Jupiter).

 

[EDG]

Ah right. It isn't Assiniboia that's missing moons, but rather the Regina system that's missing a gas giant... ("Grandfather's Worlds", Challenge 27)

Well he moved it from beyond Assiniboia's orbit anyway, so it wouldn't make a difference to a realistic system.

Though reading that article again, it kinda highlghts one reason that I find the Ancients so annoying - they're not really dead and gone like a good mysterious ultratech progenitor race should be, because Marc keeps coming up with ways to keep them around and interfering with things...

 

[Gee4orce]

I don't think the presence of a significant atmosphere is a problem for a moon of a gas giant - witness Titan.

...which skirts the edge of Saturn's magnetosphere and so doesn't get bombarded by high energy particles.

How do we know what Assiniboia's magnetosphere is ? Is there a direct relationship to GG size or composition ? Is it to do with 'metallic hydrogen' at the core ? I'm not a planetary scientist, so genuinely intrigued....

Capture is a very unlikely scenario. GG's don't just pluck planets out of their orbits .

I thought capture was the most likely explanation for the orbit of Triton in our solar system ? Granted, Triton is probably a lot smaller than Regina, but it's not totally impossible..

 

[EDG]

How do we know what Assiniboia's magnetosphere is ? Is there a direct relationship to GG size or composition ? Is it to do with 'metallic hydrogen' at the core ? I'm not a planetary scientist, so genuinely intrigued....

It should be related to size and rotation period at the very least - at nearly 8 jupiter masses, Assiniboia should have a lot of liquid and solid metallic hydrogen in its depths. Though tbh I dunno if anybody really has a good grasp on what the internal makeup of superjovians would be - I'd imagine there'd be even more weird phase changes going on in there at such high pressures and temperatures, moreso than we see at Jupiter and Saturn.

Either way, one can assume that Assiniboia probably has a very powerful and very extensive magnetic field, at the very minimum equivalent to Jupiter's.

I thought capture was the most likely explanation for the orbit of Triton in our solar system ? Granted, Triton is probably a lot smaller than Regina, but it's not totally impossible..

It's not impossible, but it's generally considered to be very unlikely because the smaller body has to be approaching the planet from just the right orbit. And also IIRC you need a third body to be captured (which gets ejected from the system) - in Triton's case it may have been a small moon that it had to balance out the energy/momentum transfer.

Also, capture would probably result in a weird orbit and lots of tidal heating, which Regina doesn't have in the canon version.

 

[daryen]

Yup, I was the one suggesting that Speck be a hot Jupiter. (Thanks for remembering, EDG!)

I was so bummed when you figured out that Regina couldn't be that nice and a GG moon. Sometimes, reality bites ...

And, on another point, I am willing to bet that Regina was inspired by Yavin IV. And why not? The idea of such a lush planet with such a cool sky view is spectacular and wonderfully different. Pity it's impossible.

 

[alex_greene]

Still, one day I can't help but imagine Grandfather emerging from his pocket universe, wandering on over to the Regina system, and saying to himself "Oh, that's where I put it. I knew I'd put it down somewhere ..."

*cue massed groaning from the system builder grognards*