Relativity

[Supplement Four]

If one wanted to disregard the notion that the Jump Drive somehow fixes the problem of relativity and time dilation, how would one go about that, easily, in the game.

Let's say the March Harrier, on Aramis, jumps to Natoko, spends a week there, then jumps back.

For the crew of the March Harrier, three weeks has passed. A week in jump going, a week in jump returning, and a week spent on the planet.

If the pilot of the March Harrier left his sweetie on Aramis, how much time would she experience while the Harrier spent that three week trip to Natoko?

Is there an easy way to figure this out?
(Any type of science never was my best subject.)

 

[far-trader]

Not sure I follow. Are you looking to make the 1 week jump equal to FTL travel of 1 parsec in 1 week and wanting the relativistic effects of that?

(not that I can answer it, relativity always gives me a headache, but making the question/answer clear will help, maybe )

 

[Spinward Scout]

There's never been time dilation calculations for beyond the speed of light because we know of no real world particles/objects that can move faster than that. The closer you get to c, the more your mass increases and the more time slows down realative to you. Theoretically, by the time you reach the speed of light, your mass and time frame would be infinite.

There is no real world way to calculate what you are asking.

So, I'm not sure if there's an easy way to do what you are asking and have everyone agree on it.

Might be better just to make it up for the sake of your game as a house rule.

 

[mmbutter]

Let's say the March Harrier, on Aramis, jumps to Natoko, spends a week there, then jumps back.

For the crew of the March Harrier, three weeks has passed. A week in jump going, a week in jump returning, and a week spent on the planet.

If the pilot of the March Harrier left his sweetie on Aramis, how much time would she experience while the Harrier spent that three week trip to Natoko?

Three weeks.

 

[tbeard1999]

If one wanted to disregard the notion that the Jump Drive somehow fixes the problem of relativity and time dilation, how would one go about that, easily, in the game.

Let's say the March Harrier, on Aramis, jumps to Natoko, spends a week there, then jumps back.

For the crew of the March Harrier, three weeks has passed. A week in jump going, a week in jump returning, and a week spent on the planet.

If the pilot of the March Harrier left his sweetie on Aramis, how much time would she experience while the Harrier spent that three week trip to Natoko?

Is there an easy way to figure this out?
(Any type of science never was my best subject.)

Maybe this can help.

First, figure out the *equivalent* fraction of lightspeed that FTL travel simulates.

Then, using the chart below, each day in FTL will result in "Time Multiple" days passing in the real world. So, if FTL=.99 times the speed of light, 7 days in FTL = 7 x 7.088812 days (or about 49.5 days)

Speed	Time Multiple
0.9c	2.294157 
0.92c	2.551552 
0.95c	3.202563 
0.98c	5.025189 
0.99c	7.088812 
0.999c	22.366272 
0.9999c	70.712446

Hope this helps.

 

[mmbutter]

When a ship spends a week in jump space, a week passes outside as well.

 

[Supplement Four]

Maybe this can help.

First, figure out the *equivalent* fraction of lightspeed that FTL travel simulates.

Then, using the chart below, each day in FTL will result in "Time Multiple" days passing in the real world. So, if FTL=.99 times the speed of light, 7 days in FTL = 7 x 7.088812 days (or about 49.5 days)

Speed    Time Multiple
0.9c    2.294157 
0.92c    2.551552 
0.95c    3.202563 
0.98c    5.025189 
0.99c    7.088812 
0.999c    22.366272 
0.9999c    70.712446

Hope this helps.

Not bad, TBeard. But, we need to simplify it for a game.

I think a time multiple based on days spent in J-Space might work. So, the ship spent two week in J-Space (one week on Natoko, for a total of three weeks). We need a multiple x 14 to get our time dilation.

Something like that, something that simple, is what we need. One number, multiplied by the number of days spent in J-Space.

The question is: Which number do we use?

 

[far-trader]

The problem is it breaks down because you're travelling much FTL not near C as the chart is for. As you approach C* the time dilation increases exponentially(?) iirc you can never exceed C only approach it, and as you do the energy required to accelerate approaches infinite, your mass approaches infinite, and the time dilation effect approches infinite (I think IF you could attain C time stops, and if you exceed C time retrogrades)

The thing is in Traveller, moving across ~3.26 light years in 1 week (a J1, increase that for higher jumps) and removing the whole non-relative(?) boundry the way you want means you're going, what, some 169.5 times C (that is much much FTL)

* as I said relativity always twists my brain and I tend to Homer off and I've forgotten everything I might have thought I knew and understood so the above should be taken as absolutely uncertain until shown otherwise

 

[far-trader]

I say ignore the theory and pick a fun game rule. It'll keep you sane and nobody can say you're wrong and start trying to fill your head with Einstein and Hawking

 

[Thoth-Amon]

When a ship spends a week in jump space, a week passes outside as well.

This is the simplified rule i use as well.

Thoth-Amon

 

[Supplement Four]

When a ship spends a week in jump space, a week passes outside as well.

Heard ya the first time you posted. You didn't read the OP. I wasn't looking for the Traveller rule.

The problem is it breaks down because you're travelling much FTL not near C as the chart is for.

True. We're speculating here.

I say ignore the theory and pick a fun game rule. It'll keep you sane and nobody can say you're wrong and start trying to fill your head with Einstein and Hawking

I was looking to play around with a quick-n-easy rule that at least seems somewhat plausible (like an author writing a sci-fi novel).

Of course it can't be true. We don't believe FTL travel is possible at this stage in our understanding.

But...what if it was? Would there be time dilation effects?

Interesting to ponder...

 

[mike wightman]

If one wanted to disregard the notion that the Jump Drive somehow fixes the problem of relativity and time dilation, how would one go about that, easily, in the game.

Let's say the March Harrier, on Aramis, jumps to Natoko, spends a week there, then jumps back.

For the crew of the March Harrier, three weeks has passed. A week in jump going, a week in jump returning, and a week spent on the planet.

If the pilot of the March Harrier left his sweetie on Aramis, how much time would she experience while the Harrier spent that three week trip to Natoko?

Is there an easy way to figure this out?
(Any type of science never was my best subject.)

This is your original post.

Time dilation and relativity only occur as you get close to the speed of light.

A traveller ship can jump with zero real space velocity. The jump drive doesn't fix this as no fix is needed, it ignores relativity by going outside of our universe.

According to your example the sweetie on Aramis has to wait three weeks to see her love again.

If you want time dilation then the ship in jump experiences less than a week while a week goes by outside (or borrow from CJ Cherryh's work and have the jump as instant for the crew but several days/weeks for the outside world). Or you could randomise it for fun.

The reverse is also possible, the jump could take a month for the crew while only a week passes in the real world.

 

[Supplement Four]

Time dilation and relativity only occur as you get close to the speed of light.

A traveller ship can jump with zero real space velocity. The jump drive doesn't fix this as no fix is needed, it ignores relativity by going outside of our universe.

According to your example the sweetie on Aramis has to wait three weeks to see her love again.

You're not understanding the OP question. I understand how the OTU works. I was speculating on adding time dilation effects to an unofficial TU.

Nobody's questioning the OTU here.

The thought is: Because the ship, when it jumps, would have to move faster than light to cover the distance it covers, how would that fly in the face of time dilation?

Because we don't understand (or even think possible) moving FTL, we'll assume that time dilation effects do occur just as they would if the ship were moving near lightspeed.

Maybe even faster.



Simple calculations: J-1 trip = 3.26 LY per week.

One could say that 3.26 + 3.26 years + 1 week passes on Aramis while the Harrier makes the trip to Natoko.

Six and a half years...to jump one parsec away.

Interesting...

Boy, what would that do for interstellar economics?



Even more interesting...

A ship with a bigger J-Drive would have greater time dilation effects. A J-3 drive would take 9.78 years one-way, yet the crew only experiences a week.

To jump out 3 parsecs, spend a week on that world, and jump back would take nineteen and a half years (+1 week ) from the POV of an observer on the starting world. Yet, the crew ages only one week.

This little technicality would make for an interesting campaign dynamic. I mean, we're entering Joe Haldeman territory here.

 

[Supplement Four]

To jump out 3 parsecs, spend a week on that world, and jump back would take nineteen and a half years (+1 week ) from the POV of an observer on the starting world. Yet, the crew ages only one week.

Gods! Think of the bookkeeping that would need to be done in order to figure imports and exports with a 20 year time delay!



1: Worlds would be self-sufficient. They'd have to be.

2: There would be a demand for J-1 vessels. Close jumps would have the minimum turnaround of 6.5 years. But, if there is no world close (no suitable world), then the larger J-Drives will be needed.

3: Every time the PC's visit the same world, it might be like exploring a new world. "When was the last time we were here? 40 years local?"

4: Technology would boom? From the PC's POV, they'd jump to a world, maybe pick up some tech, then jump back, and the new tech they picked up is already outdated on the origin world!

Mucho thoughts on this...

 

[far-trader]

I think I like that dynamic as the simplest way to do it. Just track Traveller time (interstellar travelling) in weeks (1 week per jump) and track universe time (interstellar travelling) in years using the distance covered.

But...

...you do end up with the whole Forever Soldier (Merchant, Scout, etc.) issue. Why trade with a world a parsec distant when getting there will mean your merchandise is (relatively) 3.26 years out of date (or double that if you made the call based on the latest news from the world. For all you know, by the time you get there that widget you filled the hold with will have been improved on locally, or dropped entirely in favor of something else.

While it might be interesting it will be a tricky universe to set up and play in. It won't be The Imperium we know

Just how old would the news of those upstart Terrans be upon that first meeting when it finally got to Capital?

EDIT: hehe, thinking along similar lines, typing while you were, carry on

 

[Supplement Four]

I think I like that dynamic as the simplest way to do it. Just track Traveller time (interstellar travelling) in weeks (1 week per jump) and track universe time (interstellar travelling) in years using the distance covered.

Yeah, I needed a quickie, easy to figure, rule. It seemed logical (and as good as any).

A J-1 vessel makes a round trip, one parsec out and back, in 3.26 + 3.26 years + 1 week. 6.52 years + 1 week.

A J-3 vessel makes a round trip of one, two, or three parsecs in {(3.26 + 3.26 + 3.26 years) x 2} + 1 week. 19.56 years + 1 week.

So, if you've got to get goods from 1 parsec away, you'll want to go with a vessel mounted with a J-1 drive. The J-1 ship makes the round trip in 6.5 years, while the J-3 ship makes the same run in 19.5 years.

I like how that makes the J-1 ships important. They can't go as far, but they're quicker on the shorter runs. The bigger J-Drive ships can go farther, but it also take them some time.

That's an interesting role playing and story-telling dynamic.

While it might be interesting it will be a tricky universe to set up and play in. It won't be The Imperium we know

Agreed. I wonder if as many worlds would be settled. Probably not.

Then again, closer worlds, regardless of their hospitality, would be important for time reasons.

You'd probably have little clusters of worlds and satellite worlds colonized.

It's an interesting concept to ponder.



From a total rpg perspective, Travellers (the PCs) would be loners. They'd have no family unless those people were on the ship with them. The call to go into space must be strong with them, indeed. The cost would be high.

 

[far-trader]

...Travellers (the PCs) would be loners. They'd have no family unless those people were on the ship with them. The call to go into space must be strong with them, indeed. The cost would be high.

Yep, something like Gypsies, only how do you justify multi-millon credit wagons?

EDIT: Multi-generational of course! Silly me

An interstellar Navy (at least on the order of the Imperium, even a small ship 1st Imperium) would be a harder thing to justify in many ways.

Interstellar Navies for individual worlds perhaps. A coalition of a couple or a few close worlds maybe.

 

[mmbutter]

This is the simplified rule i use as well.

As far as I can tell, that is the canon interpretation.

 

[mike wightman]

I think I understand now - you want to ponder on the what if the jump drive didn't map to real time in the real universe

I quite like the idea that the ship crew experience a week in jump space but the real world has them travelling at the speed of light - so just add 3.26 years to the travel time per jump number. Not exactly time dilation though.

This would make communication between worlds even more limited than the age of sail model, making local representatives of the nobility and megacorps even more important for decision making.

Using such a model would severely limit the size of your interstellar community, unless you have a method of communicating faster.

Orson Scott Card's Enderverse springs to mind where ships can travel near lightspeed so the passengers arrive in a new system in a week or a month but years/decades may have passed in the real world. So interstellar voyages tend to be one way trips, since if you travel far enough by the time you return home everyone you knew would be dead.

There they have the magic of FTL comms to keep a semi-coherent interstellar society.

There's a similar problem in C J Cherryh's alliance universe in the years before FTL travel was discovered, the STL ships flying at high near c speeds would make journeys between systems in weeks/months of ship time but the stations they travel between have years passing. This leads to the difference in societies between the ship crews and the station born.

 

[Supplement Four]

I think I understand now - you want to ponder on the what if the jump drive didn't map to real time in the real universe

Now you're gettin' it. We're just a-ponderin' here. Thinking about "what could be".