Habitable Planet Found Only 22 Light Years From Earth!

[Neil]

In The Coldfire Trilogy humanity expanded to distant stars in a big batch of "colony ships" launched from Earth with the goal of perpetuating humanity's existence. The author, in one of the few works of sci-fi/fantasy to observe the laws of physics as relates to space travel, describes the ships as not being able to move faster than the speed of light. So the hook is all the colonists were essentially in permanent "cryosleep" and the automated ship basically traveled from planet to planet performing analysis on its habitability for human life before landing and waking the colonists up.

Because of this the descendants of the original colonists know that in their case it took tens of thousands of years for the original ship to make its journey. Further, because the ships had no idea where they were going when they left, and because of the reality of how long it takes for communication to travel that distance, there is not ever any communication with Earth. There was no goal of establishing a linked human empire because it was just impossible, but instead creating new worlds where humans could be self-sufficient. Fulfilling some vague species goal of creating many different worlds of habitation to insure the species perpetuates (I guess until the heat death of the universe.)

So while even that fiction involves massive increases in technological sophistication in regards to space travel, I think the key really will be biological changes to humanity itself. Even then, if we ever do send people to other stars it'll be much more in this vein of establishing new, but not connected, human societies. There's just no realistic way to maintain significant ties to planets on other stars.

Did you happen to see Pandorum by chance?

I did.  Creepy.

[Neil]

Well, like Neil said, the eclipses don't last that long.  Each side will be in night for half its orbital period, but I assume we're talking about an Earthlike moon, with an atmosphere.  That will moderate global temperatures quite a bit.  Assuming Callisto distances (to get away from radiation) and velocity, an eight day night is no big deal.

Neil might know this, though: would the magnetosphere of an Earthlike moon afford sufficient/any protection from the radiation belts of a jovian?  That is, could a larger moon be closer than Callisto and not be a deathtrap?

I'm not sure how the presence of the giant would affect the dynamo, but it should provide some protection, barring some kind of magnetic recombination.

[Ideologue]

The geodynamo should still function; it's still rotating, after all, even if it's tidally locked to the planet, albeit more or less slowly than the Earth.  I don't think it would stop convection, and we can assume an iron core since anything else would be surprising.  On the other hand, it have to be at least Earth-sized, since we're right on the edge of a functioning convective core (at least, that's my understanding, based on my understanding of Venus--only slightly less massive--and its buoyant lithosphere that prevents proper heat transfer from the outer core to the surface, relegating geological activity to catastrophic surfacing events, which is bad for other reasons than a non-functional geodynamo anyway).

Speaking of giant moons, though, there's no reason an Earth-sized moon couldn't be captured by a jovian, is there?  Obviously we don't see any in our solar system; afaik there's no planetary evolutionary reason to believe they can't, but I might be wrong.

[CountDeMoney]

I did.  Creepy.

Yeah, but it was an interesting premise, and I didn't see that ending coming.  Thought it was very cool.

[Neil]

The geodynamo should still function; it's still rotating, after all, even if it's tidally locked to the planet, albeit more or less slowly than the Earth.  I don't think it would stop convection, and we can assume an iron core since anything else would be surprising.  On the other hand, it have to be at least Earth-sized, since we're right on the edge of a functioning convective core (at least, that's my understanding, based on my understanding of Venus--only slightly less massive--and its buoyant lithosphere that prevents proper heat transfer from the outer core to the surface, relegating geological activity to catastrophic surfacing events, which is bad for other reasons than a non-functional geodynamo anyway).

Speaking of giant moons, though, there's no reason an Earth-sized moon couldn't be captured by a jovian, is there?  Obviously we don't see any in our solar system; afaik there's no planetary evolutionary reason to believe they can't, but I might be wrong.

The capture mechanism would probably work the best, but I can't say for sure what the effects of three billion years of close interaction with the forces of a large giant planet would have on a dynamo.

[Razgovory]

Well now I have a new movie to watch.

[OttoVonBismarck]

I haven't seen Pandorum, and I don't remember if the author of the Coldfire Trilogy ever expanded on the fuel for the colony ships. The three books are basically fantasy setting with a sci-fi origin story, so there is passing mention to the "original colonists" and such, but it isn't a major part of the books so it wasn't fully fleshed out.

[Darth Wagtaros]

Coldfire by C.S. Friedman. Never read her other stuff. That one was good.  Gloomy though.