Bit of Discourse: FTL

[Simon_Jester]

One relevant point is that in a setting where intergalactic travel is theoretically possible, it may still nevertheless have not been done. It was probably possible for someone to sail across the Atlantic using existing ship technology well before anyone actually did so, or at least before there was any evidence of it happening. As it stands there is no evidence anyone did so prior to about 1000 AD, and even that expedition left so little evidence behind that it more or less took modern archaeology to prove to people's satisfaction that it wasn't all a myth. It took the 1492 expedition (which was launched in relative ignorance of what was out there, instead hoping to find something that definitely wasn't there) to actually put the Americas on the map of the Old World.

Even given galaxy-hopping technology that can cross the galaxy in days, the major galaxies of one's own local group are still weeks or months of sailing away. Ships may not have the endurance to cross such a gap; even if they do, it may be that no one sees fit to organize expeditions to other galaxies when there are more easily exploited opportunities 10-100 times closer to home.

[Me2005]

I've understood some described methods of FTL to have a maximum reasonable range or a need to 'star-hop' (they can only jump between systems and not into points in the interstellar void). They might be instantaneous to a system 10 or so Ly away, allowing them to cross the galaxy in weeks, but cannot make a single jump across the galaxy (or to an adjacent galaxy). They might also have pre-plotted coordinates of the locations of stars in their galaxy to improve jump speed, but accurate coordinates for stars outside their galaxy would require processing/observation powers beyond those carried by the ship to plot.

[Eleventh Century Remnant]

Yes, I know, it took me far too long to get around to posting here- light cones, yes, but it's kind of an astronomical commonplace, isn't it? In fact I think I personally first came across the idea, had two and two put together for me in the science fictional sense in, hm, when did Traveller; The New Era come out? '92, 93? Something like that.

(Survival Margin, incidentally, next only to the People's Glorious Revolutionary Adventure, may be IMO the best roleplayng supplement ever written. It is a headline by headline account of the assisted suicide of a galactic empire; articles from the news services of what actually happens when the centre cannot hold, and a sclerotic, arthritic, bureaucratic state finally bursts in a torrent of rage and frustration that fuels a multi- sided, fratricidal civil war. Lord knows where you'd find it now, probably PDF.)

And in a desperate attempt to swerve back on topic, I'd like to talk about the difference that drive speed or jump range makes to the setting. Does the map still matter? Also, if so, what kind of map? The number of potential destinations, the complexity of the reachable universe, increases with the cube of the range of the drive.

I actually suspect that very long range drives would have a globalisation- like effect on the galaxy as a whole; there would be a handful of places that everyone had heard of, would know by reputation- like the largest sites on the internet- and be familiar with, and you're looking at a map more like a social than a physical network of connections from there on out, and the fact that you can go anywhere would kill off the middle layers of most trades and specialisations. Go to the best, or go local. Planets of Hats might actually exist- forced into hyperspecialisation to be of any use at all to the broader galactic economy. Populations would be able to mix, aliens would be commonplace, and all the fun that that implies.

Shorter ranged drives like those in Traveller (again, justifying tangent)- low single digit parsecs per week- mean you have a more complex local environment; each system, each pocket, has to be sufficient in the bulk items, importing specialties and rarities only. Limited reach of drive allows economic and social microclimates to be much more possible.

In a way, I think that is the only actual reason for going out into space- not to do, as such, because there's very little that you can do in space that can't be done much cheaper on earth, except go into space, and they don't make self licking ice cream cones that big; you don't go there to do money things or for good economic reasons, we might go there in order to be. To lead different lives, to experiment with different ways of being a society, of putting ourselves together. I expect great diversity, among the stars. Then all those cultures will start evolving, adapting, cross- fertilising- the future could be tremendously wierd, if we give it a chance.

Moving far enough and fast enough for intergalactic travel tends to throw all that into a blender, so I'm not particularly fond of the idea. In terms of what's actually possible, it looks like Alcubierre has a range limit of the endurance in other aspects of the craft; until you deflate the warp bubble, basically- which means you could in theory have a faster than light generation ship on it's way to the next galaxy. Just mind that bow wave. Wormholes inflated out of the vacuum, hm, not sure.

[Ahriman238]

Sure, there's drives that effectively teleport you a distance of light-years. Most of you probably know the idea from nBSG.

Range matters with this sort of drive, but so does the time you have to spend between jumps. In the Three Galaxies game setting, a ship with Rift Drive can generally only jump three or four times a day. Contrast with Mutineer's Moon's Enchanach Drive where the ship teleports to the edge of it's range, hangs around for three femto-seconds and jumps again, tracing a flickering course of flight at an effective 1600 c. As nBSG and Stargate Universe showed, there can be a lot of drama into falling into a dangerous situation and trying to survive long enough for your jump engines to recharge.

Then there's the question of destination, you'd hate to pop up in the wrong place. The plot of the Lost in Space movie (I know, I know) was that without a hyper-gate forming a distinct beginning and endpoint, you'd be zapped to any random point in the universe. Which the characters do to themselves deliberately, figuring that anywhere has to be better than falling into the sun.

[krakonfour]

I'm having great difficulty in finding a certain science fiction series where spaceships travelled using fold drives. These fold drives are limited in reach, so they are used several times to cross a certain distance: they're stutter drives.
Each time the ship re-enters normal space, it leaves a signal of light and radiation. The ship's trip can be traced as a string of pearls across the sky.

The setting dealt extensively with having FTL travel without FTL sensors. One important factor was the 'light cone', which is the position of an enemy ship given as probability distribution. As time passes, the cone gets wider and you are less likely to be at that certain point. The origin of the cone (the tip) is the first after-image received.
This also allows tactics such as these:
-Jump in, fire a laser beam at the target.
-Jump closer, fire the laser from another direction.
-Jump yet again, and fire from a third direction.
-All three laser beams hit the target at the same time, before the light from the first afterimage reached the enemy and warms him of your presence.

The setting also had egg-shaped battlecruisers kilometers in length, crewed by only a few dozen people, and supposedly, cutting them in half just created two half-powered ships.

Seriously, where is it?!

[krakonfour]

Yes! YES! http://www.kentaurus.com/exordium.htm

[Ahriman238]

Sorry, krakonfour, I have no idea.

Another thing that occurred to me is the effects of the jump on passengers. In the classic Stephen King short story "the Jaunt" a family is taking a routine teleporter trip to another planet in the solar system. The father passes the time until departure by quizzing and teaching his children about the history of the Jaunt and why everyone puts on a mask and breathes in the happy sleeping gas, because everyone who doesn't goes insane or dies. I won't spoil the ending for you, assuming that didn't just do it, but that's the first time I remember the idea of drugging people or sticking them in cyro before using FTL, to avoid issues. I think there are other places that have done it, but I can't remember one.

Another idea was in the Lukyanenko novel "the Stars are Cold Toys" which uses a similar jump system, well, two. One has a range less than half the other, but is safe for everyone. The long-legged one causes catatonia, madness or death to most aliens, but for humanity is a high better than sex or drugs. This little discovery leads to humanity being enslaved as a race of starship pilots, which is better than it sounds as the aliens would have exterminated us if we hadn't been useful to them in some way.