[TML] "Dies the Fire"

[shadow at shadowgard.com]

On 10 Dec 2007 at 20:41, Richard Aiken wrote:

> On Dec 10, 2007 5:54 PM,  <shadow at shadowgard.com> wrote:


> > It gets really difficult to avoid gravity levels that'd make Mesklin
> > (cf Hal Clement's "Mission of Gravity") look like a low gee world at
> > the edges of the disk. Plus, with my design at least, it gets
> > unreasonably hot ion the inner edge.
> 
> Then this would be the Hell of this megaworld.  The place the Balrog
> calls home.  I mean, you'd have to be able to use magic like regular
> creatures use air to be able to live there.  If such creatures could
> travel to the more hospitable latitudes, they'd get worshiped as gods.

Given that the flat surface near the rim is gonna be red hot during 
the day, the conditions are more than bad enough. If it wasn't for 
oxidation problems, you'd be able to have lakes of molten lead. 
Probably too hot for lakes of sulfur.

> > And you forgot the outer edge. Colder than hell. But the gravity
> > thing gets you again.
> 
> Then the outer edge is Hel (one "l") - the polar opposite of Hell.
> The place where the natives are things that even Ice Giants are scared
> to think about . . . :-)

Again, without getting too close to the edge (or going over it) it 
gets *really* cold. At night, much less in the permanently shadowed 
places, it's going to be *frozen* air.

> > Given that there *isn't* any such thing as orbital velocity (not
> > until you are dozens of AU out, anyway) and that escape velocity is
> > in the thousands of km/sec range, you could have some really high TL
> > societies that never got to a fraction of the disk before dying out.
> 
> Along this line, I was doodling through DriveThruRPG just now and saw
> a campaign setting called "Castlemourn" by Margaret Weiss Productions.
>  The Players Introduction is apparently old enough that it's now free
> (priced at $0.00).  I haven't "bought" it yet, but according to the
> reviews it's an extremely balkinized fantasy realm where hundreds of
> years ago there was a catastrophe that shattered the land, so severely
> that nobody remembers what caused it and most are afraid to ask.
> Before the catastrophe, almost everyone could use minor magical
> cantrips.  But now only dedicated mages and clerics can do so.  So
> lots of folks assume the event had to do with magic and thus shy away
> from same.  There are seven gods, but these are - at least according
> to one of the reviewers - more akin to monsters which must be appeased
> than deities to be respected and emulated.  Best of all, the Players
> Guide is written from the point of view of a newly-arrived party,
> folks who have come into the setting through a magical gateway from
> somewhere else.
> 
> Add the details from these threads and *POOF!* instant campaign!  :-)

Heck, the place is big enough to fight *several* full scale nuclear 
wars without seriously inconveniencing anyone more than ten thousand 
or so km away. :-)

> > > Ah.  But we aren't PCs.  We'd have to walk every step of the way.
> > > When it's PCs, the GM just says, "After climbing down the Long Stairs
> > > for a week (living off the weird plant and animal life along the
> > > ledges as you go), you come to this huge iron door . . ."
> >
> > Not my idea of fun.
> 
> <shrug> Well, I never did finish "The World Of Tiers" myself.

I've read all the books. Wasn't that thrilled with the last one (#6?)

> > Given that the gravity (and thus convection forces) drop as you
> > approach the midpoint, there's not going to be much driving any flow.
> 
> But wouldn't the mass of descending air on each side accumulate a
> serious amount of inertia?  I mean, the Sun keeps endlessly bobbing
> back and forth through the zero-gravity region at the disk core.  It
> looks like a stream of air could do the same.  Maybe those permanent
> tornados are *inside* the holes, rather than above them?

The sun doesn't have to worry about friction, nor about density waves 
going thru it.
 
> > It'd take one hell of a pressure difference to get the flow going and
> > keep it going. But if there was a pressure difference, consider that
> > there's a *lot* of atmosphere, and it could flow for a long time.
> 
> If you get it travelling around among holes that open at differing
> altitudes, would "a long time" become "effectively forever?"

Not really. Because "different altitudes" doesn't matter. Consider a 
tunnel here on earth between a point high on a mountain and deep in 
the valley below. 

You don't get an airflow due to the different altitudes. That's 
because the presure varies with altitude the same way on both ends of 
the tunnel.

What would get a flow going would be if the pressure at a given 
altitude above the zero-gee plane on side A was different from that 
at the same altitude above side B.

> > For that matter, consider your ten or one hundred mile wide hole
> > being at the bottom of an ocean on one side (or both)
> > I don't want to try figuring the pressure at midpoint.
> 
> "20,000 Leagues Under The Sea" for real!  But why worry the extreme
> water pressures at midpoint, when the air in a non-flooded hole won't
> fall pass that point because it's in zero gravity?  BTW, how could you
> have a hole that only opens into ocean on one side?  Seems to me that
> if you didn't have an ocean on one side to start with, you'd have one
> on both after the hole opened!  :-)

Nope. Same reason as with the "open air" hole.

The height of the water above the zero gee plane will be the same on 
both sides. So whether there's an ocean on either side will depend on 
how far from that plane the terrain around the hole is.

BTW, come to think of it, in most places, the holes would tend to 
accumulate water (and dust and rocks) in the middle. Anything that 
falls in will get slowed to terminal velocity long before the center. 
And that's not enough to carry it far past the center. So eventually, 
it'd come to a stop at the center. 

Rocks will accumulate easiest. Water drops (rainfall?) will merge 
into bigger drops as the gravity goes down. So eventually there'd be 
water all the way across the center or else if there's a net airflow, 
a mass of breaking and reforming blobs of water displaced in the 
direction of airflow. 

This will tend to trap dust, so you'll eventually get muddy water. 

There are other processes that'll tend to make water accumulate 
unless it's really hot down there.
 
> Hey!  I just thought of a design reason for having big holes.
> Incoming debris - comets, asteroids, etc - can't be destroyed without
> the pieces continuing on to impact the disk anyway.  So if there isn't
> enough time for robotic tugs to steer such debris away from the disk
> entirely, big holes exist to allow a chance at passing safely
> *through* it.
> 
> -- 
> Richard Aiken
> 
> "Never insult anyone by accident."  Robert A. Heinlein
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--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com