There is no moon.

[LostSoul]

I'm getting a sense from this thread that everyone else runs Newtonian heliocentric universes. Am I really that exceptional?

I ran a world where the "earth" was the only world that there ever was, or would be. The sun and stars were the souls of creatures on the other side of some firmament. They would fight each other and move around and that's why you could tell the future by reading the stars. Beneath the earth we had the void, which was a black mess of souls/demons all getting intermingled with each other (you could see them in the sky as well). The sun was God, who just sat back and watched everyone; I never did come up with anything for the moon.

There was no heaven.

 

[Umbran]

When a planet's core cools, the planet starts to shrink and the crust buckles, creating escarpments.

Yep, but that's basically a one-time only deal. You get one cooling, and then it's done. You don't get continual renewal of your surface. You don't generate new mineral deposits, or recucle carbon that way.

I'm not talking about generating features. There's forces that will shape what land is there. But in the end it all goes away, claimed by entropy. I'm talking about generating new land.

It can also take quite a long time for, say, an Olympus Mons to wind up being flat and uninteresting, even with erosion.

Well, most of the Appalachians are barely qualifiable as "mountains" anymore. They're more like really big hills. As opposed to the Rockies or the Himalayas. And that's only a difference of a few hundred million years, IIRC. As compared to the billions of years it took for life to evolve. Depending when your tectonics freeze, you're prety likely to end up with only the small stuff.

Sure, you can pick any time you like, obviously. But if you're going to pick a pseudoscience rationale, it then seems a bit odd to then have to pick a more unlikely variant on that riationale to get what you want. Might as well just drop the science altogether at that point.

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

None of which would be currently extant if water remained on the surface to continue erosion. By comparison to Earth, Mars has diddly for erosion, and has been that way for a long time.

 

[Rel]

Well, most of the Appalachians are barely qualifiable as "mountains" anymore. They're more like really big hills.

I would have begged to differ upon reaching the tops of several of them, had I been able to catch my breath for a minute.

(your point is taken however)

 

[John Morrow]

Yep, but that's basically a one-time only deal. You get one cooling, and then it's done. You don't get continual renewal of your surface. You don't generate new mineral deposits, or recucle carbon that way.

Agreed, though I could probably imagine a collapse that takes place in stages. Could created an interesting cataclysm cycle for a setting.

I'm not talking about generating features. There's forces that will shape what land is there. But in the end it all goes away, claimed by entropy. I'm talking about generating new land.

Sure, but like Niven's Smoke Ring, nobody said that a setting had to be stable or eternal. A setting only looks at a slice of time and that slice is what needs to work.

Well, most of the Appalachians are barely qualifiable as "mountains" anymore. They're more like really big hills. As opposed to the Rockies or the Himalayas. And that's only a difference of a few hundred million years, IIRC.

The Arcadian Mountains in New York State are a bit over 300 billion years old. But a part of my point was that none of those mountains started out being as large as Olympus Mons, which rises 25km above the surrounding plain. Start out with really big features and, sure, they'll wear down but it could take billions of years.

As compared to the billions of years it took for life to evolve. Depending when your tectonics freeze, you're prety likely to end up with only the small stuff.

Being from the Northeast, the "small stuff" can still be mighty interesting. Actually, thinking of the "small stuff" around here, there is another mechanism that can push up some land. The Watchung Mountains are a terminal moraine. Of course those same glaciers also took their toll on those Arcadian Mountains in New York.

Sure, you can pick any time you like, obviously. But if you're going to pick a pseudoscience rationale, it then seems a bit odd to then have to pick a more unlikely variant on that riationale to get what you want. Might as well just drop the science altogether at that point.

As I think I said in my original reply, the bigger problem you'll have with a solid core is that you won't have a magnetic field. That leaves the solar wind ripping against your atmosphere, among other things. But as Venus shows, the absence of a moon does not necessarily mean the absence of a molten core. I'll agree that a solid core would not be my first pick for a setting, no would no moon, if for no other reason that it eliminates an interesting astronomical feature that we're really used to.

None of which would be currently extant if water remained on the surface to continue erosion. By comparison to Earth, Mars has diddly for erosion, and has been that way for a long time.

I think that erosion would still have some work to do on Olympus Mons, even with Earth's erosion. I understand your point and it's a good one. My point is simply that it could take a billion years for features the size of Olympus Mons to wear down to the size of Whiteface Mountain and that sort of mountain is plenty big enough to make a role-playing setting interesting, if there were some other compelling reason to set up that geology. And, yes, like Niven's Smoke Ring, it's days would be numbered, as are Earth's in the big scheme of things.

 

[painandgreed]

The Arcadian Mountains in New York State are a bit over 300 billion years old.

More like 300 million as the age of the universe is somewhere under 20 billion years.

 

[talinthas]

Now you know what would be cool? A campaign on this world where the object was to create a moon for this planet. Perhaps the moon acted as a lock or a gate blocking off the nether planes, and was destroyed in a giant demonic ritual early on. Since then, the world has been open to assaults and stuff, till a group of heroes comes and figures out a way to create a new one...

Or, something like the Dragonball universe, where the moon is destroyed to prevent Goku from transforming into a giant ape and destroying the planet.

 

[Lonely Tylenol]

Well, I'll be. That's actually relatively accurate; the transfer of rotational energy from the earth gradually slowing down does elevate the Moon to a higher orbit. I had forgotten that until I looked it up after seeing your post.

Although that's an interesting campaign idea right there -- a really ancient world, with very, very long days and nights, and a moon that stays in exactly the same place in the sky at all times. A world with such prolonged days/nights (a single cycle taking about month) would have a hard time getting conventional vegetation to grow well, and would likely have temperature extremes due to the prolonged heating or cooling of the sun.

I wrote a campaign setting in which all the land masses were floating islands in the upper atmosphere of a gas giant. Days and nights were about a fortnight each.

 

[John Morrow]

More like 300 million as the age of the universe is somewhere under 20 billion years.

You are correct. Million, with an "m". I was considering writing it as "a third of a billion years" or something like that an never fixed it. Ugh.

 

[Desdichado]

None of which would be currently extant if water remained on the surface to continue erosion. By comparison to Earth, Mars has diddly for erosion, and has been that way for a long time.

Wind erosion is still ongoing. Plus, there's a lot of support for the theory --still not mainstream, however-- that Mars' current condition is a lot more recent than previously assumed. Personally, I think that theory has a lot going for it, although it'll probably never be resolved without geologists actually going to Mars.

 

[mhensley]

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.

Actually, the no moon idea was just to make things a little different. Most fantasy settings I have read either have our one moon or several moons. Why not no moon at all?

This is a fantasy world, so it doesn't have to follow the laws of physics. I certainly doubt that I would mess around too much with the length of days or extreme changes to how the earth works. But a few differences would add a bit of flavor to the campaign.