There is no moon.

[physicscarp]

There is a wonderful out of print book titled What if the Moon Didn't Exist? which deals with this very situation. It's written by Neil Comins a professor of astronomy and physics. In it,he explores a number of "might have beens" such as,

What if the Moon Didn't Exist?
What if the Moon Were Closer?
What if the Earth Had Less Mass?
What if the Earth Were Tilted like Uranus?
What if the Sun Were More Massive?
What if a Sta Exploded Near Earth?
What if a Star Passed Near the Solar System?
and What if a Black Hole Passed Through the Earth?

To be sure, his treatment is scientific, but meant for a layperson. I highly recommend it for this type of discussion.

Also, I just bought a writer friend of mine World Building which discusses how to create viable life bearing worlds for science fiction writers. I'm sure it could be applied to fantasy worlds as well.

 

[Umbran]

Well, Mars and Venus are pretty geographically spectacular, despite Mars being pretty dead geologically and Venus having no Moon.

Yes, but they also have no erosion to speak of. If you have static tectonics plus erosion, you eventually get something remarkably flat and uninteresting. All your mountains wind up as silt at the bottom of your oceans.

 

[fusangite]

Don't get that sense. The thread self-selects for discussion of Newtonian heliocentric arrangements, so it isn't a solid indicator.

Good point.

Honestly, even though I'm a physicist by trade, I generally don't specify the astronomical arrangement for my fantasy worlds. I describe what the PCs see, but they aren't in a position to know the exact layout. I only specify it when I feel it is relevant.

But you must have some sort of default physics for answering basic physical questions that the rules don't cover like projectile trajectories, electrical conductivity of substances, non-magical causes of/explanations for illness, physical causation and teleology, etc. when these issues come up.

 

[Umbran]

But you must have some sort of default physics for answering basic physical questions that the rules don't cover like projectile trajectories, electrical conductivity of substances, non-magical causes of/explanations for illness, physical causation and teleology, etc. when these issues come up.

The way you talk, you'd think I'd want all my players to be physicists or something

The combat system is quite abstract. There's no need to go into details of trajectories. The player doesn't need to know the details, as the character has a BAB that covers how he fires a ranged weapon, or a skill that covers the design of a seige engine.

The only electricity the PCs have access to or knowledge of is magical in nature, and so need not follow normal physical laws.

Medieval medicine did without germ theory - it was based in simple and non-rigorous trial and error. Folks did medicine for centuries without having a correct explanation of biology. And there's an abstract skill that covers the player knowledge. Why should I need to stipulate specifics?

Physical causation and teleology? Dude, these are adventurers, not philosophers. I've never had the word "teleology" come up in a gaming session.

The principle of least action as applied to gaming - don't create more than you have to, lest you write yourself into a corner later.

 

[Mark]

I was thinking that my new campaign world would not have a moon. How would this change things? What would the earth be like without the moon? For one thing, it sure would be dark at night. Maybe that would explain why so many creatures developed dark vision.

Looks like more trouble than it is worth. Why not just have an invisible moon so you don't have to change the physics of anything and change most reference or use of a moon to reference or use of the stars. Might have to still mess around with a few things but it would be generally easier than having no moon at all.

 

[Harmon]

There is a really good show on Discovery about the Moon and its influence on the Earth though I can not for the life of me remember what its called- sorry.

The Moon is leaving us, one inch a year. Millions of years ago the Earth turned fast enough that our days were 14-16 hours long. As the Moon gets further away the Eearth will slow even more and the days will lengthen even more.

Tides will decrease in size and the ocean movement will slow (this is millions of years from now), which should decrease the tempature changes on the Earth (convection will decrease).

The Earth's axis are based on the Moon, so without it we would wobble over to our side and back up, changing the predictable yearly cycle.

I have heard that the molten Iron core of the Earth is spun or assisted by the draw of the moon's own very weak core, thou I do not recall where I heard this.

With regards to running a campaign in a moonless world, toss science and all that, say its magic or whatever- hell dude it's fantasy.

Good luck with the campaign.

 

[coyote6]

So, the real moon may have shielded Earth from meteor impacts.

Therefore, a fantasy moon may have helped bar periodic demonic invasions. So, in the absence of a moon, you get a world that suffers from irregular episodes of a sort of demonic Wild Hunt, where some gate to the netherworld of your cosmological choice opens up, a bunch of fiends come through, and set off to maim, slay, corrupt, etc.

Therefore, settlements tend to have strong redoubts -- shelters that the inhabitants can flee to when the Stars Are Right.

Naturally, these strikes have occasionally toppled kingdoms. Thus, some of those shelters are scattered around the land, lost & abandoned. And full of who knows what sort of treasure, secrets, and/or menaces . . .

(Any resemblance to, say, Earthdawn is entirely to be expected, 'cause Earthdawn had such a wonderful excuse to have all kinds of dungeons around. )

 

[John Morrow]

Yes, but they also have no erosion to speak of. If you have static tectonics plus erosion, you eventually get something remarkably flat and uninteresting. All your mountains wind up as silt at the bottom of your oceans.

When a planet's core cools, the planet starts to shrink and the crust buckles, creating escarpments. That's another way to get surface features, though I'm not sure how violent the process would be or how long it would last. It can also take quite a long time for, say, an Olympus Mons to wind up being flat and uninteresting, even with erosion. Yes, some day your fantasy world may be flat but it doesn't have to be there yet during the time the game takes place. Could be interesting playing in a world where all of the mountains are old and worn down.

Venus also seems to have at least some tectonic activity despite having no large moon. Of course Venus also seems to have suffered it's own major impact in the past, leaving it rotating backward. So maybe it's simply more important that something large smash into a proto-planet than it is for the process to actually create a large moon.

 

[Desdichado]

Yes, but they also have no erosion to speak of. If you have static tectonics plus erosion, you eventually get something remarkably flat and uninteresting. All your mountains wind up as silt at the bottom of your oceans.

What are you talking about? Many of Mars' most spectacular features are caused by erosion -- either wind or past water.

 

[cignus_pfaccari]

And there is no other possibilities for flavor? Such as in eastern mythology where creatures who seek to upset the natural order take human shape?

Or a created race of warriors and spies?

Brad