I have been following the discussion on correcting the physics of
Traveller. This is something to which I can relate. Being a physicist,
it annoys me that games often ignore physics in places where there is
no reason to ignore it. Obviously FTL travel can cause some physics
problems depending on how you handle it. Traveller does what most people
and games do these days - FTL exists because you "leave" the universe as
we now know it and enter jump space (hyper space, warp space, ...).
However, what I'm writing to address is the discussion on maneuver
drives. These have been referred to as "reactionless" drives and people
have been trying to decide how one can have a reactionless drive. Before
I give my version of the answer, lets step back for a moment and consider
what is going on.
Maneuver drives get their power from fusion power plants. In Traveller
the preferred material for fusion is hydrogen and the end result is
helium. This brings up the first question - where does the superheated
helium go? The best place is out the engine exhaust but then you don't
have a reactionless drive. This means that the helium is somehow contained
and cooled then dumped someplace or maybe the hot helium is just vented into
space or used as fine adjustment thrusters the point is something has to be
done with the end product. I would shoot it out the exhaust and take
advantage of the extra thrust (conservation of momentum you know). Getting
back to reactionless drives - you now have some (large) amount of energy
that you want to use for propelling the ship. How do you do it? Simple
expend the energy out the exhaust. Since this is energy and not particles
this would (in some definition) qualify as a "reactionless" drive. Look
at Star Wars space ships, notice the bright glow in the exhaust of the
engines and how it gets VERY bright just before "accelerating to light
speed"? This is still conservation of momentum (energy/speed of light).
If you prefer some sort of gravity based propulsion system then
consider this: Gravity can be viewed as a curvature of space or the result
of exchanging gravitons (a form of electromagnetic radiation). If we
look at gravitons then anti-gravity is the generation of anti-gravitons
which cause two masses to repell each other. Then your back to exhausting
electromagnetic radiation (granted a rather interesting form of EM). So
consider adjusting the curvature of space so that you ship (or grav-
vehcile) will slide down the "gravitational hill". To get a craft to
hover you would need to "flatten" the already curved space near a planet.
To rise you would need curve space so that the gravitational potential
is lower in the direction that you want to go. Assuming that some kind
of machine can be made that can efficiently exchange energy for space
curvature then this is a truely reactionless drive. All you need to do is
take the energy from the power plants and counteract the gravitation
potential. The problem is (if I remember by Traveller right) that the
books say that gravity (anti-gravity) drives work better near large masses
(I assume they think you need the gravity to push against) but if you are
curving space, your drives would work better in flat space where you don't
need to nullify existing curvatures (ie far from planets). However, if
you take the graviton approach then the drives will act like the book says
because the force (repulsive) is a function of the separation.
In my games, I usually don't try to explain such things but when I
have to I use the graviton explaination. To me it seems more plausable.
Clearly, "reactionless" maneuver drives is another place where the physics
has to take a backseat to playability or you say that maneuver drives are
not reactionless and be done with it. In any event this is my two cents
worth on the matter. Comments?
Tony L. Hayes
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T.L.Hayes |
MIT/Lincoln Laboratory |
Lexington, MA |