Gliese 581g - A Tidally Locked DnD World

[Stormonu]

Y'knw, I betcha that if one were a lich who wanted to be left alone do to one's studies, a great place to build a fortress would be the dark pole of the planet.

Hmmm...or perhaps a lich who's powerful enough to tidally lock a planet and create a barren wasteland in which to conduct his studies and whatnot...

 

[tankschmidt]

Already published!

Judges Guild put out an adventure on such a world back in 1981. It's more like a miniature campaign setting, which is what adventures tended to be like back in those days.

The title is "Portals of Twilight". The adventure is similar to what others have already mentioned; there is a narrow strip of habitable land, an uninhabitable hot side, and a icy cold side with frost monsters. North Pole City is the major outpost of civilization, and there is indeed a constant wind.

You can probably pick it up at a good game store or online for less than $10.

 

[jonesy]

Judges Guild put out an adventure on such a world back in 1981. It's more like a miniature campaign setting, which is what adventures tended to be like back in those days.

The title is "Portals of Twilight".

I'm guessing this one?
Portals of Twilight (1981) - Judges Guild | DriveThruRPG.com

I have to say it does look interesting.

Edit: oh look, the link broke, and is pointing at the wrong one.. hmm..

For some reason it won't let me link directly to it. It's here, and only $3:
http://rpg.drivethrustuff.com/index.php?manufacturers_id=31&filters=0_0_0_0

 

[Xeviat]

Rotation

A tidally locked planet does rotate, though; it rotates once every time it orbits the star. So it's planetary day is equal to its year. Relative to the point of the star, it doesn't rotate, but it is most definitely rotating. Gliese 581 g itself orbits its star every 37 days, so it completes a rotation every 37 days. This is 37x slower than Earth's rotation, so the coriolis effect would be much smaller, but it's going to be there.

How would this affect air currents?

Oh, and those interested in tidally locked worlds should look at these sources:

Aurelia and Blue Moon - Wikipedia, the free encyclopedia
and
[ame=http://www.youtube.com/watch?v=CNeTxPgGJ7I]YouTube - Extraterrestrial[/ame]

 

[Silverblade The Ench]

Undead and maybe illithids would have a field day in the "dark" areas, and plant creatures likewise in the "bright" ones., hm?

you could also have odd or catastrophic "seasonal" effects if the orbit isn't very circular.
Like our Milankovitch Cycles, but worse. Imagine mega hurricanes encircling the twilight belt....

 

[AdmundfortGeographer]

D&D had a tidally locked world.

It showed up in Spelljammer's Practical Planetology. Called Radole.

 

[Klaus]

Back in 2e, my home world of Jera was much like this in the past.

Pyrois, the day side, had magma, desert islands ruled by blue dragons and all manner of fiery things.

Cryois, the night side, had icebergs, white dragons and all manner of cold stuff.

The terminator band was dense with vegetation, from tropical jungles in the middle to scrublands near Pyrois and tundra near Cryois.

The work of the legendary heroes Ironheart and Steelaxe made the world spin again.

 

[Nifft]

The work of the legendary heroes Ironheart and Steelaxe made the world spin again.

Just proves you can fix anything with magnets.

"Iron-y", -- N

 

[Desdichado]

Yes, but those planet-wide weather systems, no matter how severe, would eventually reach a near-steady state and essentially never move after that.

The planet is not rotating, and coriolis force from Earth's rotation is a large part of what causes weather systems to move.

I don't see that as a "but" but rather as an "in addition to.

Yes, energy would be transferred by weather. Evaporation would always occur *here*, an endless wind would transfer the moisture over *there* to where it never stops raining, rain would fall, and the water would flow back to the sea. The main difference with Earth would be that the highs, lows, and fronts are permanent.

There are plenty of mitigating factors that can be introduced, if you want to, though. Tidal forces from Gliese 581 could stretch the planet, sorta how Io is stretched by tidal forces from Jupiter (although probably less extreme if we want to assume that this world is habitable.) That can actually change the landforms sufficiently to alter weather patterns, plus it causes substantial vulcanism which would also disrupt weather patterns. Considering that Io, for example, has numerous active volcanos at any given time, you'd probably not have much in the way of steady state weather.

Of course, that may make things more difficult to establish any kind of steady state environment at all, but that's either a big problem or an interesting challenge, depending on how you look at it.

This also assumes a circular orbit, which it doesn't have to be. A more elliptical orbit could create seasons just by distance from the sun, which could cause weather to do unusual things as well.

Tidal pull from a moon or moon(s) around the planet could also be used to vary the weather somewhat if you wanted.

And finally, if you assume that there's no Jupiter or other large gas giant in a mid-level orbit around the star, then there's no shield to gravitationally capture or deflect errant comets. The star itself becomes the main comet and asteroid attractor in the solar system, and a planet with a near orbit around it finds itself unwittingly in the line of fire.

I presume, of course, that this planet is actually closer to its sun than the Earth is to our sun, since Gliese 581 is a much smaller, cooler and dimmer star than our sun. In order to get similar climate, the orbit would have to be much closer, but I confess that I don't actually know what the situation for the real Gliese 581g is.

 

[Klaus]

Just proves you can fix anything with magnets.

"Iron-y", -- N

Zing!

To provide more context: Ironheart and Steelaxe were blatantly inspired by Fafhrd and the Gray Mouser. Ironheart was a human barbarian with a chainmail like Warduke's. Due to a curse, he had his heart replaced with an iron one. Steelaxe was a short human with two handaxes of returning.

The religion was basically the Egyptian Pantheon.

And this "pre-history" was also heavily inspired by Golden Axe.