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Why a week in Jumpspace?

S

stofsk

SOC-13
Ever since I got into Traveller, this question has always been at the back of my mind. Traveller's jump drive is pretty unique in that no matter what the jump rating, you will always spend a week in jump-transit. (unless you misjump, but let's not worry about that)

My question is: why did they (the original creators of Traveller) decide on this?
 
For one thing it keeps things aging at the same rate as the outside Universe. It also gives a finite amount of time to delay communications and set the economics around it. And it gives time for Roleplaying between the characters. These are simply IMHO, but they are definitely reasons.
 
I would venture to guess that Marc and company came from the War Game crowd. As such, turn based moves were the norm. Now, take Traveller as an interstellar wargame and the week in jump space becomes the default turn sequence for this. Fourth Frontier War, Trillion Credit Squadron etc, all used that "1 Week = 1 Turn" mechanism.

I think that the 1 week in Jump Space regardless of the distance travelled is one of the things that sets Traveller apart from every other RPG out there. It shows very clearly that Jump Space is NOT Normal Space Plus.
 
The distance between systems has to be in weeks of travel in order to give the impression of an ocean voyage, and hence the communication time lag.
That all jump travel takes one week regardless of actual distance travelled is an excellent feature - I think I agree with Plankowner about its wargaming roots.
 
What also comes to mind is the digital nature of jump drive. Isn't the default time 150 hrs, more or less?

For those who postulate an analog system, like myself, the time might become more variable, especially at high tech levels. My Terrans can overcharge their jump drives in certain circumstances to get more performance, though the time remains proportionate.

Of course, they don't really understand their drives, either...
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Originally posted by Plankowner:
I think that the 1 week in Jump Space regardless of the distance travelled is one of the things that sets Traveller apart from every other RPG out there. It shows very clearly that Jump Space is NOT Normal Space Plus.
Click to expand...
Wholeheartedly agreed.
 
Well, my old crew used to meet once a week for an RP session. At one stage I tried to make it so that the sessions began by coming out of jump space, and ended by going back into it. The week of jump space gave a neat gap between adventures.

I also think that one week is "just right". I mean, it's long enough to be boring, but not so long that it would stop you from seeing a good number of different worlds before you die.
 
It also is just long enough that it drastically reduces business off-world, but short enough to not kill it entirely. The exact ratio of curtailment is arguable (highly so), but that it will have a curtailing impact is a definite. ANything you need in under 3 weeks you need to find local suppliers for.

It also sets the stable size of the imperium at MaxJump*24 parsecs radius... the maximum commo-speed being the same as max jumps with 0 turnaround for a "pony-express" style system. (this is based upon the historical findings that empires tended to collapse or compartmentalize once a 6-month lag for orders making it to the front occurred.)

It has one other nifty benefit: it is a memorable time unit, and, outside the orient, a sevenday is a common timekeeping unit. (premodern Japan used 3 weeks of 10 days...) SO it's a "Single unit jump"
 
I don't know the original reasons for the week, but IMTU I devised a formula for Jump travel, giving some variation in journey time, whilst maintaining it around one week. I used:

T = cube root(D+c^2) where D is distance and c is lightspeed, all in SI units. (seconds and metres)

This gives jump times ranging from about 5.25 days for J0 (intrasystem) to about 8 days for J8 (my limit). Obviously there is also some variation due to chance - you can't have these things too predictable, can you?
 
IMTU jump works by projecting a ship, cocooned in a bubble of normal space, through a wormhole. (See here for further details.) That wormhole is a quantum incursion into jumpspace. Now although the ship exists in its own bubble of normal space and thus normal physics apply to it, the wormhole itself is governed by the physics of jumpspace. The shortest temporal event possible is 1 chronon, which in our space is 2x10^-23 seconds but in jumpspace is 6x10^5 seconds (about 7 days).

The other piece of the puzzle is the mapping of our time onto jumpspace time. There are three temporal interfaces with jumpspace: between normal space at the wormhole entrance, between the normal space in the jump bubble, and between normal space at the wormhole exit. Since when jump is initiated the wormhole is created, the wormhole entrance interface can be assumed to be locked in step. (This may not be the case in catastrophic misjumps.) This leaves the other two interfaces some degree of variability. Because misalignments cause turbulence and thus drain energy from the system there is a tendency for these other two interfaces to be closely synchronised. However, even in a non-misjump situation, it is possible for the end-point to vary by upto +/- a day, and the duration for the travelling ship to vary independently by upto +/- a day. The degree of variance in either is a factor in how violent the exit from jumpspace is.

(However I would be surprised if this was the reason the original authors thought of at the time.)

Regards PLST
 
Originally posted by Hemdian:
The shortest temporal event possible is 1 chronon, which in our space is 2x10^-23 seconds but in jumpspace is 6x10^5 seconds (about 7 days).
Click to expand...
Interesting concept. I like it. I'll give that one some thought. Maybe the conversion factor could depend on ship velocity or gravitational field in some relativistic way. Hmm.

Not sure about your chronon duration though. It may be a typo in the wikipedia or just a different concept that I'm not familiar with, but when I was studying, the accepted value for a chronon was around 10^-43s. - 10^23 is the Mole.
 
Originally posted by Icosahedron:
Not sure about your chronon duration though. It may be a typo in the wikipedia or just a different concept that I'm not familiar with, but when I was studying, the accepted value for a chronon was around 10^-43s. - 10^23 is the Mole.
Click to expand...
Having a little hunt round the net there seems to be some confusion between a chronon and Planck time. Planck time was defined in 1899 (as 0.539 x 10^-43) as a conveineant time unit for physicists to use, before the idea of a chronon was conceived. Further, it appears that the exact value of a chronon (if it infact exists) has not been determined, so there will be different values from different authors. The Wikipedia article talks of the P. Caldirola model setting the chronon's value at 2x10^-23 in 1980. However, for our purposes here the key thing is the idea of chronon itself ... an indivisable unit of time (regardless of its actual value).

Regards PLST
 
Originally posted by Dominion Loyalty Officer:
What also comes to mind is the digital nature of jump drive. Isn't the default time 150 hrs, more or less?
Click to expand...
168 hours actually but yeah round numbers 150 isn't far off. MT (AFAIK) was the first ruleset to postulate +/-10%. Giving you between 151 and 185 hours, usually in a bell curve so it tends to be closer to 168 than the extremes either way.
 
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