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(TFT) Re: Demon slingshot
At 13:35 -0500 3/23/06, TFT Digest wrote:
From: Ed Thorn <prophesor@yahoo.com>
He also has a lot of time on his hands. :)
Would that that were generally true! But I have trouble focusing on
many kinds of work on planes. And I spend a fair fraction of my time
on planes. Sigh.
Honestly, Mark, all I wanted was confimation of my '17' answer.
Oh. OK, 17. I guess I could have saved a fair amount of typing... :-)
This all sprang from a setting where medieval-flavored PCs would
encounter the remnants of a post-magocaust society. The 'launch
tower' you speak of was to be one of the facilities explored.
Cool! The collapse of Industrial Magical Civilization as we know it?
My answer to the tower vacuum problem? Elementals, with task "keep
it all out of the way". It's a handwave, I know. But consider it
more a somatic component. :) It also lets me have enraged and
deranged elementals greet my explorers.
LOL. Yeah, that fits. And if anyone could do it, they could.
My answer to the tower wall impact problem? Correction gatepairs,
with minute angular offsets from perfectly level.
I thought about that, but since the correction angle keeps changing
as the demon moves faster and faster, I couldn't figure out a simple
formula for making it work. But maybe they have a rule that just
passes the payload if it's far enough from the center of the tube?
I also put the 'launch' entry gate above the stacked accelerator
gatepairs. It has the rule to activate when proper velocity has
been reached. It's mated gate points up in the example given, but
could also be pointed at an enemy city, or whatever.
Nicer than my approach, it's automatic that way.
Yes, on the enemy city. And if the lead wizard on *that* project has
a sense of history, his double-layered quote on the first use of that
weapon will be, "I am become Vishnu, destroyer of worlds." This is a
really serious weapon.
I love the self-orbital demon. But would he not have to see the
point 90 degrees 'before' his orbit, which he wants to teleport to?
Good question! I assumed that the ability to force a summoned demon
to teleport you anywhere implied that summoned demons have a better
targetting system than wizards do for that spell, or else that
summoned demons have already *been* everywhere and can remember it
all.
But a demon, or even a wizard doing the same trick, could just walk
to the equator beforehand, and then use his memory of the spot to
target, I think? I'm assuming the Long-Distance Teleport spell is the
one needed here, as opposed to ordinary Teleport.
That would force the orbit to a minumum radius determined (I'm old
school, here...) by a circumscribed square around the planet. That
does seem higher than might be desired for spying or weapons
platform uses.
Agreed with that, though the slightly lower orbital velocity there
might save a bit on gates.
And the question was in english units because I still think that way.
Sigh. Until we convert the leaders, the masses will never follow... :-)
I also had never considered the use of a 'braking tower'. Bravo!
I think Niven did this first? A story called "all the bridges
rusting" maybe? Don't remember the exact reference, but it's not
original with me, I'm pretty sure.
From: "David Michael Grouchy II" <david_michael_grouchy_ii@hotmail.com>
Ed,
I seem to remember something along the following was suggested during the
original thread.
Fill tower with created hexes.
Seal tower.
Drop created hexes.
Good one! Though you'd have to be sure the tower was built out of
something that didn't outgas.
From: pvk@oz.net
Subject: Re: (TFT) Mark Tapley hits one into orbit
Where would wizards get the 20th Century knowledge of gravity, friction,
vaccuums, angular correction for planetary rotation, the idea of space
above the atmosphere, orbits, etc? Why would they care? (Rhetorical
questions...)
This bothered me for a while. Without the value of Mu, most of the
rest of the plans fall apart. Here's the chain I'd expect:
1) Radius of planet measured by something like Eratosthenes'
technique, could be good to 1% or so (Eratosthenes was).
2) Surface gravity measured by dropping stuff in a drop tower,
probably also good to around 1%.
3) Use Self-powered Flight or Carpet to go up to around 100km
altitude. Altitude verified by angular depression of apparent limb of
planet (ie, how far down is the horizon from straight level?). This
also allows incremental improvement of vacuum gear - go up until you
turn blue, come down, build a better vac-suit, try again.
4) Hang a launch gate out over the North pole and build the facility.
5) Launch Proxies out of it, using various acceleration times. A
little too long, and they'll be at a higher altitude over the south
pole. A little too short, they'll reenter before getting there. Just
right, they'll be same altitude over the South Pole as over North,
and you have found circular velocity.
Once you know the correct drop time for low orbit, you have a good
check on your initial estimates for Mu and rPlanet, or at least one
set of values. Going to geosynch with Long-Distante Teleported
Proxies could give you another, and you can estimate the distance
there from the apparent diameter of the planet against the star field.
This still relies on having a good clock; I'm not sure exactly how to
solve this problem. Good pendulums are not bad, but you'll have to do
measurements down to sub-second values with good precision.
As for the rest, experiments with the Drop Tower would be a harsh but
effective teacher.
However, if someone did begin this sort of experiment, and if it were
possible to specify gates that changed velocity or direction of velocity
while conserving amount of energy (which, I don't think is true),
Agreed, and note that any gate that spans more than a few hundred km
does exactly this even for people just walking through it, if
referred to an inertial frame.
then I'd
think this would become the new super seige/terror/destruction weapon of
Cidri. To heck with the vaccuum and demons - drop a big rock in there, and
set the exit gate to point at your desired target - kinetic energy from
... heck.
Yup. I tried to design my systems so that they would work with an
inanimate payload, not require a demon or smart wizard as the only
passenger (though I ended up having to have a smart wizard as the
"pilot").
Interesting to leave out the requirement for vacuum. Depending on how
big your rock is, it might have a pretty high terminal velocity. But
if you want tens of km/sec, you want good vacuum.
* Demon-launching *is* hysterical and a classic story problem and
solution, but it doesn't really hold up, I think.
Hah. Just wait until I start in on my relativistic heavy demon
collider...unstable demon isotopes anyone? Demonium-235?
:-)
* Gates "work" in a way that makes sense to medieval folk. One _walks_
through and _walks_ out the other side, of a _place_. To a medieval mind,
even a wizard, some huge distance up in the air is not, I think, a place,
unless there is something there (floating sky castle, magic carpet, etc.).
Without checking AW 'cause I lack time at the moment, I don't think a gate
could redirect an extremely fast object to some other vector - I think
it'd probably slow down to something fairly close to the destination's
frame, as it passed through. Or, if it can, then I'm afraid this may have
become a pretty wicked WMD...
The only defense I've been able to think of is to first use a crystal
ball to predict use of the weapon, then mount an invasion to destroy
the facility. I'd think you could enlist a *lot* of allies in that
crusade.
Even Reverse Missiles will probably be ineffective against the shock
wave and UV radiation, though it could be harsh on anybody around
the exit end of the targetting gate. (I assume the attackers would
have sense enough not to make the targetting gate 2-way.)
For the peace of mind of all of the inhabitants of Cidri, I'd sure
like to think PvK is right about this. But that Niven story has
pre-warped my mind to be able to get around objects whipping through
gates at really large velocities, so I just can't figure out how the
metaphysics prevents it. The Gate paragraph does allow throwing stuff
through the gate IIRC, so up to at least some small velocity it works.
PS. On return methods (the "Rise Tower"): Took a class at UT on space
systems design. Project was to design a system to get a specified
payload and 6 astronauts into orbit. One guy on our team pointed out
that there was no (stated) requirement to get them back. One gal on
our team, named Ellen Crippen, turned out to be the daughter of Bob
Crippen, and was *definitely* *not* amused. Since then, I've always
tried to think about how to undo trips...
--
- Mark
Cell Phone: 210-379-4635
office: 210-522-6025
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