Actually, the physics papers I took taught us that you would have to worry about relativistic effects above 10% of lightspeed. Still, if your calculating travel times from acceleration you would probably want to get a computer to calculate it (to allow quick calculations when you change something), meaning that special relativity is easy to account for.

Another interesting result is that under special relativity, any FTL travel is equivalent to time travel . But that is probably hidden in 40k by the ways that the warp screws with time.

I might point out in some of the fluff it's possible, but risky, to come out of warp deeper in system. (Cain's Last Stand has an example of this)

Bilateralrope said:

Good point, both about precision and the case of special relativity. I'll try to explain how I think, and hopefully make it a bit understandable even for people without physic stuides. In RP-games I usually don't worry if the speed of travel is below ~80% of the speed of light, because then the relativistic effects are generally way below 1% of the "mechanical" data. The relativistic effect becomes potentially much larger if you are calculating properly on accelerating things (aka the general Theory of Realtivity) instead of approximating things by counting as if things were in non-accelerating motion (aka the special ToR). But I've only spent one year of university on my physic studies, so I don't know how to calculate the effects of the general ToR :-( I have understood it can be **** tricky, so I make do with approximations.

Interesting article. And yeah, 40k has a lot of strange issues with causality and the speed of information. For one, the astropaths can communicate FTL. With the right priority codes it is possible to send a message across the galaxy in just a matter of months, maybe even weeks if you are lucky.

People more clever than me have made up ways to integrate the strange warp effects better with relativistic theories. One is to see the warp as "somewhere else" where distances doesn't match the distances in "real space" and a timeprogression that doesn't match either. So it is not a question about higher speeds, but rather shorter distances and other measurements. It is our feeble inability to measure this effect properly that gives the impression of FTL communication. Compare with if you draw two dots (start and end on our trip) on a blank paper (the Real Space). If you lay the paper flat you can measure a specific distance between the dots, and if you leave a snail to crawl between the two dots, you can easily time the snail and calculate the average speed of travel. If you instead fold the paper so the dots end up practically touching eachother and let the snail eat its way through the paper from dot a to dot b the travel time will be much faster... Then pretend that the flat paper is your whole world, you have no concept of "height", and you cannot imagie the folding of the paper. Then you would have to come to the conclusion that this snail is travelling at FTS-speed (faster than snails).

So the astropaths and the navigators they can look at the horribly complex origami that makes up the galaxy, and they can guide messages and ships from spot to spot by jumping between the papers. To continue the above metafor, they can think in three dimensions while most of the mortals can only think in two. The Astronomicon is like a powerful flashlight that shines through the multiple layers of paper, making it much easier to see where it folds and to know what direction you are going in. Also, it might be more appropriate to think of Realspace and the Warp as two very wrinkled papers that are crumpled up into a ball. So it is quite possible to take shortcuts by jumping between the two papers, if you know where the connections are, how to navigate the other paper and how to get across.

Psykers, they have understood that there is something powerful outside of the paper they are living on. And if they set fire to their paper, they might be able to open a small hole to get some of that into the paper to do cool things for them. Mostly they just burn paper though...

All arguments considered, I'll still be sticking with Abnett-space-travel-time I think. ;-)

Wow! Thanks for posting the data from White Dwarf and re-formating it into a random table. By way of comparison, here's something from the original 1987 Rogue Trader rulebook:

"A warp drive, or warp engine, is a device that enables a spacecraft to enter and leave the medium of warp space. … The distance travelled in this way is called a jump , and a jump may be of 1 to 4 light years depending on the conditions prevalent in warp space. Such a journey typically takes between 1 and 6 days of real space time, contracted into 1-4 hours of perceived time for the spacecraft. A spacecraft plunged into warp space at random will travel at 1-4 light years per hour of perceived time/36 hours of real space time. While in warp space a craft is isolated from real space. However, psychics are able to maintain or establish telepathic contact if they are sufficiently strong, if they are human astropaths for example." (page 131)

If we take it from here, I see two ways to go about. Either figure out in greater detail what Rick meant by "depending on the conditions prevalent in warp space", or simply going by randomized rolls all the way.

If the latter, then:

o A jump takes 1d4 light years, will consume 1d6 days of real space time, and feel like 1d4 hours for the crew on board.

o Once inside the warp, the sheep will travel at 1d4 light years per hour of perceived time (or, per 36 hours [1.5 days] of real time).

That table is a good idea for when the Navigator blows his rolls.

I don't find it that hard. I just have a GM binder I keep GM stuff in and two of the pages are Excel sheet 'calendars' to keep track of basically the date in-game. In DH it didn't matter that much, but in RT where some actions routinely take over a week, or even months, it seems prudent to just keep track on a calendar.

Terrible necropost is terrible, but does anyone know where I can get this? I used to have it, but it appears to have disappeared into the ether.

On 11/6/2009 at 9:16 PM, nick012000 said:

aramis said:

What happens, however, with the lack of communication is a reliance upon speculative trade, rather than presold carriage-freight.

Or the mandatory trade generated by tithes. You can be **** sure that there will be a market for an Agri-world's food at a Hive-world, or a Hive-world's guns at an Imperial Guard fortress-world, and there's a decent chance if you're a Chartrist Captain that that's all you'll ever be hauling.

The exact value of which will depend upon how much has already arrived in the recent unit of time. If you have excess above tithe, and the other two hive worlds nearby also did, and got to the fortress world first, you may be stuck with the remainder... if you get there first, you're likely to be able to actually sell the excess for a good bit of whatever the fortress world happens to have .

Tithe movement, given 40K warp travel time uncertainty, is essentially speculation for the recipient....