> Secondly, ShadowCat is a very knowledgable person. Reading his
> reply, I thought it a bit terse, but I did ask for opinions and what-
> not.
Shadow. I know a ShadowCat on LJ but *she* isn't much like me. :-)
> I prefer a Hard SF Universe, and that will probably mean no fake
> gravity. However, I wanted to come up with an idea on how it might
> be created/used in a Universe that had it.
Well, my take goes with the "gravity is just the curvature of space"
model. Give that jump drives seem to care about that sort of thing
(and use it) it's not unreasonable.
It's also rather more workable than the "graviton generator" in that
it's "easier" to have things happen that match stuff from canon (or
"assumed" so long that it's effectively canon.
But you can use graviton/antigraviton generators and still have much
the same principles.
Working principles:
1. the internal gravity of the ship is generated somehow and
*adjustable* on a very *local* basis (there are references to being
able to adjust the gravity of a cabin)
2. The gravity doesn't extend outside the ship. This avoids a number
of problems. It also introduces a few "interesting" effects.
3. "inertial compensation" is "just" a tie in between the "grav
plates" (or whatever) and the drive. Have the ship going at 6 g in
one direction and the grav system imposes a 6g force in the
*opposite* direction. Resulting in a net acceleration of zero.
Ok, the acceleration due to gravity is a function of the "slope" of
the gravity well, not the depth. The "energy" tied up in a gravity
well *is* tied to the depth. So this is a plus.
Principle 1 means that the gizmos responsible for gravity
(hereinafter referred to as "grav plates") will be a very distributed
system. Probably built into every deck and overhead.
Principle 2 means that the net effect on the universe has to be zero.
Which means that the plates are going to be paired, and there will be
odd effects at the "edges".
empty space -----------------
/\
Ship's field ----/ \ /-----
\/
Or something like that. Some day, I'm going to do up a graphic for
this and put it up on the web. The two sections angled this / way
should be *much* steeper and the section angled this \ way should be
shallower.
The field will reverse near the top and bottom of the hull. And where
it reverses, you are going to have "interesting" tidal effects.
The most "extreme" version would have the / sections vertical, and
the transitions at true angles. Which would result in some problems
with infinite gradient changes. So the transients are problem
"curves". With the "tightness" of the curve being proportional to the
strength of the tidal effects.
Expect warning labels near the transitions. They are probably
"inside" the plates (which are probably a lot more complex than the
word "plate" implies).
Other likely details. Establishing a field takes power. And if the
plates are working, lowering it *gets* energy back. Minus losses of
course. Sort of like charging a capacitor.
This makes for the lovely arcing wires and the like that folks are so
fond of if a plate takes damage and the energy can't go back into the
power system. Also makes working on an active grav plate more than a
bit nerve wracking. Between the tidal forces and field reversals
inside, the thing could practically blow up in your face if you
accidentally kill the power.
Power to maintain the field will likely be low (ideally it'd be
zero). But any time anything *falls*, the energy for the fall has to
be supplied by the plates (Energy = force times distance travelled).
Lifting things puts energy back into the field. Don't forget losses
both ways.
Knock over a large object (say a stack of cargo containers in the
hold) and there *will* be a big drain on the grav plate power feed.
The plates in the "middle" of a ship with multiple decks may be
"idling" with just the ones at the top and bottom of the hull doing
the work. If an area is set to different gravity than the rest of the
ship the plates at the top and the bottom of the area will be doing
the work to maintain the difference.
That's likely the typical civilian setup. The "intermediate" plates
are only used for varying gravity from ship standard, and in
emergencies when the "main" plates at the top and bottom of the ship
are knocked out.
Military setups are likely to have all the plates "hot" and working
to maintain the field(s). They'll take down a section for maintenance
(with the attendant higher load on the plates above and below them)
but keep the others hot. Working on the ones in the top and bottom of
the hull gets "interesting" because puts part of the ship (the next
deck inward from those plates) in zero g if they are in space.
Knocking out a plate will probably greatly weaken the field in the
area. Unless plates above and below it can compensate.
Oh yeah, crossing between areas with different gravities is going to
be hazardous. Going from a low g to high gee area will "instantly"
supply you with the difference in potential energy. As downwards
velocity. Going the other way will require *you* to supply the energy
difference.
So for both practical and safety reasons, I expect field boundaries
to be kept to walls. And to have safety interlocks with the doors. If
there's an airlock, it'll have a plate of its own so that it can be
used as a "grav lock".
Oh yeah, those energy requirements. They mean that that favorite anti-
hijack game "grav pong" requires a *lot* of power shuffling. And may
be hard on the grav plates. Which provides a much needed reason to do
it sparingly. :-)
I'm sure creative GMs can come up with all *sorts* of ways to make
life miserable for their players based on the above.
Details of *how* the plates bend space or generate/absorb gravitons
are best avoided as some player, sometime will find a way to make you
regret them.
Oh yeah, doing the inertial compensation as in principle 3 means that
if the ship takes a hit, you'll still feel it. You just won't feel
acceleration due to the main drive.
> "Sir! We've taken a hit to Engineering. They report that..."
>
> "...that the power plant has taken damage. Very well. Direct Damage
> Control Teams to that systems and give them top priority" the Captain
> directed.
Actually the "floating away" is unlikely to happen. *If* gravity
could just be shut off, there'd be no force holding things down,
true. But it'd still *take* a force to (for example) move the coffee
cup up from the table.
Movies use the "float up" bit to show the audience that zero-g is in
effect. :-)
So it's sort of a cliche.
But consider the fun if the inertial compensators go. Or at least the
link to the drive. Picture the compensators stuck at some level. And
you need to use a different level.
Compensators pulling you towards the nose at 6 g, but you have to
drop the drive to 3 g. Oops.
Losing grav plates means rerouting power to compensate or dealing
with areas of the ship that are isolated due to differing G settings.
Not a good thing if you are trying to do damage control.
At least a *failed* plate means that the transition to the zero (or
at least lower) g is gradual. Which will feel like a *real* steep
slope.
--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com
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