Twin Planet Scenario

[Mouse]

Wow!

Thank you so much for commenting - all of you. I'm off to work again this morning, but you have given me a lot to be thinking about at lunch time, and I'll be back to read it all again this evening

[Mouse]

I have no idea if the planets are really tide locked, I just made this under the assumption they were locked.

I am going to make the same assumption

Well, that's really what it comes down to, isn't it? I mean, both Tolkein's and GRRM's worlds make little to no sense on MANY fronts - geographic, economic, militarily, the list goes on. But readers seem to like 'em.

Tolkien did at least have the advantage that the understanding of the science that would make nonsense of his world was only in its infancy at the time of writing. But I think what you're saying still holds true. I've listened to nearly 500 contemporary fantasy novels over the last couple of years, and most of the worlds they generate seem to be about as sensible as mine!

I'd say at this point you are writing space fantasy rather than science fiction and considerations of physics are no more sensible to apply than they are to Star Wars. That's fine, as long as you don't pretend it's scientifically plausible.

I quite agree for the most part. In the beginning I always thought of it as a pure fantasy, but I was told that time travel was really a sci-fi thing, and I do have 2-3 main characters who travel through time between books. I also have a time machine in the prequel, and a moon base, and... I think I'd better stop revealing too much about the plot line

Well, let's assume that the side that happens to be facing Errispa started off with a thinner and more fractured crust. Then you might well get the result that most of the triggered volcanism and seismic activity was on that side, bringing more heat to the surface.

Ok, so that's workable and I won't have to weave too many spells around it to make it fit.

Bear in mind that gravitational tidal effects will produce a similar thickness on the far side, assuming the analogy to oceanic tides hold, as I think it would. And that side still gets more sun. So, maybe you have a cold belt with two warm spots?

Hmmm. I think my immortal sentient AI/genesis pod thing has a pretty good reason for picking the habitable zone closest to Errispa (namely the need to cross the void and colonise Errispa before Ethran breaks apart), so I could have a corresponding habitable zone on the other side. Its just not mentioned in the novel because the focus is in the inhabited habitable zone.

Volcanoes also put up dust and ash which cool the planet. Whether volcanic activity serves to warm or cool on the whole depends on multiple factors, but you're fine stipulating that in this case it serves to warm things. However, all the warm air is high pressure. It will naturally move to the cold, low-pressure areas. Per your hypothesis, it will then be swept into space. This planet will not be habitable for long. You can recycle air on a tidally-locked planet if it freezes out on the dark side, air-ice glaciers push into the light, melt, evaporate, and renew the atmosphere, but you cannot get it nearly cold enough to do that with this set up.

That's the main problem - the not being habitable for long aspect. Its why the late medieval people of Ethran have to find a way to migrate to Errispa. I'm going to use a bit of artistic license here and overlook to mention the dust and the cooling - pure fantasy

The ice will lose mass pretty rapidly. Earth without atmosphere would be at about 0 Fahrenheit. You're postulating a vacuum over the ice. It's going to sublimate rapidly. Details again depend on specifics, but I'm pretty sure the loss of any ice is going to go a lot faster than the tidal locking (and a lot of liquid water is going to go along with the atmosphere in the first place, before what is left gets frozen).

I think you're better off just ignoring the physics and accepting that you're writing a space fantasy. Attempting to justify it will just call attention to the implausibilities. Keep the story moving, accept the background as given, and most readers will go along with it. Better to leave things unexplained than try to prop things up with a bogus explanation.

You're right. Space Fantasy it is

I'm happy with that.

The only reason I've spent so long not knowing what to do about any of this is because I've heard there are people in this world who like to pull authors apart as if to destroy them for all the pseudo-science they use. But, you know what? Maybe I'll just stop worrying about it and get on with the writing

I will use the really important stuff, like how far apart would be sensible to have two Earth-sized planets, but I'm going to veer away from accuracy where the (relatively speaking) smaller things like climate are concerned. Things will be as I say they are - to fit the story I want to tell

Thank you all - Azelor, Waldronate, Diamond, rdanhenry, and Kacey - for helping me make what to me was a mammoth decision

[Straf]

Woolly mammoths?

[Mouse]

Great big fuzzy ones, Straf