From: shoham@ll.mit.edu (Daniel Shoham)
Subject: Re: Unrealistic space scenes ( was: sound in space )
Organization: MIT Lincoln Laboratory
Date: Thu, 19 Nov 92 00:19:07 GMT

In article <1992Nov18.051633.18671@mel.dit.csiro.au> gre253@mis.csiro.au (Steven Green (+61 6 276 6813)) writes:
>
>Can anyone forget the all time classic of unrealistic space scenes
>
>Battlestar Galactica !
>
>Not only did they have sound in space, but fires, spaceships with "wings" that
>did banked turns and very convenient large holes in the sides of the big
>ship that let them take off and land freely yet didnt let the air rush out
>into space!

As I mentioned in an earlier post, I would rationalize sound in space (and
fires, and visible LASER shots) as a translation of events to a form that makes
sense to the human viewer (much like language translations).

Spaceships with wings are quite reasonable, if they are to make occational
atmospheric forays. The wings are not going to make any difference in a vacuum.
Notice that the large ships (that presumably never go atmospherically, at least
not very fast) are not aerodynamically shaped.

Large holes in the "spacecraft carrier" (also present on Star Wars ships) can
be believed if you assume some sort of invisible force-field that traps the
air in, and there is a technique to allow ships to go in and out - perhaps by
removing the field in the region occupied by the ship. (I think there is 
evidence that this is the case in Star Wars).

It is hardest to explain banked turns. I could do that if I point out another
unrealistic effect: the normal gravity (i.e. 1g, downward) within which all
action seems to take place - even spaceships action  (manuevering, or in stright
flight). Ah, but we all know that pseudo-gravity generators are installed in
every ship that ever been filmed. What we do not know is how those generators
work and what are their shortcomings. It is reasonable to assume that in some
of the SF universes (including the BG one) gravity generators are unable to
seamlessly change the direction of the pseudo-gravity force-vector - a needed
capability if pseudo-gravity is to be maintained during a turn. A possible
solution to that problem that must have occured to spaceship engineers, since
it DID occuer (in a different context, of course) to terrestial aircraft
designers, is to take advantage of Newtonian mechanics. A banked turn creates
an artificial gravity directed downward throughout the turn. (Or else, airliner
passengers would fly out of their seats everytime an unbanked turn was made -
this is not the reason for banked turns, changing the direction of the 
aerodynamic lift vector is, but it is a fortunate effect of banking).
Thus, the pseudo-gravity generator can be turned off as the turn begins,
allowing the turn's bank to create artificial gravity. It is turned back on
(with the new direction alignment) after the turn is compleated. After all,
it doesn't really cost anything to bank a turn in space.


- Why am I wasting my time defending "scientifically" what was clearly a
poorly thought out TV show? coming up with explainations that I doubt occuered
to the producers? because its fun! ::-))


Dan Shoham               shoham@ll.mit.edu
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