This was originally private email, but I have no objection to letting the
TML in on it, so I'll reply here.
[email removed] writes:
>
> : From: Adrian Hurt [email removed]
> : Subject: Re: potential energy in the Traveller (and other) universe
> :
> : What is the equation relating potential energy to distance, once you allow
> : for the fact that gravitational attraction is itself dependent on distance?
> : Specifically, does your potential energy increase or decrease as your
> : distance from the attracting body increases?
>
> I don't remember the formula either.
So do any TML physics experts want to tell us?
> I think that there is a certain
> amount of energy which is enough to overcome ALL of the gravitational
> potential energy of the Earth. If you assume that energy is kinetic
> energy, then you can divide out mass from the equations and get an
> escape velocity.
I believe the escape velocity is the velocity you need to have initially,
so that gravitational deceleration will not prevent you from getting to
an infinite distance, where the gravitational force of the Earth upon
your ship will be zero. Of course, other factors will probably prevent you
getting to an infinite distance from Earth in reality.
> I would say that for a jump drive to land you 1/2
> way between Sol and Alpha Centauri, it would have to expend more than
> enough energy to bring the ship to escape velocity.
Well, it will have to expend some energy in order to make up for the
potential energy it will gain due to its increased distance from Sol.
But it will get some of that back because it loses some potential energy
due to the reduced distance from Alpha Centauri. There's also the matter
of what the ship's potential energy due to its distance from Regina will
do.
> I was thinking along the lines of Larry Niven style jump drives, I guess.
> In that case, jumps are made between stars, not into open space.
This messes up the trick of a ship with a jump-1 drive but enough fuel for
two jumps, which executes one jump-1 into empty space and then a second
jump-1 to the destination, thus making a 2 parsec journey possible.
> : > True, but I don't think Traveller was THAT broken. Some of the
> : > stats might have to be altered or given further constraints.
>
> OK, so maybe altering the stats won't be enough. But Jump-4 and
> Maneuver-3 should still be understandable under the new system.
Yes, but the snag is that a ship capable of Manoeuvre-3 under the old
system will either no longer be capable of it (because the drives are
now bigger), or be capable of it but now have some new cargo space
(because the drives are now smaller).
I wonder if they will use the same sort of trick they did when they
introduced High Guard, whose calculations for drive size and fuel
consumption were different from those in Book 2 - the old drives are
standardised models, suitable for use on small ships if it is an
advantage to do so.
> Also, they should have at least the same range of weapons and
> equipment. If I have characters aboard a ship in the old system,
> I want to be ABLE to convert to the new system. And I don't want
> to have to give up my repulsor bay because these are not included
> in the new rules.
No, but you may have to give up your repulsor bay because the new
rules say it uses more power than the old rules, and your ship can't
provide the required power.
- --
"Keyboard? How quaint!" - M. Scott
Adrian Hurt | JANET: [email removed]
UUCP: ..!ukc!cs.hw.ac.uk!adrian | ARPA: [email removed]