Jumping into empty hexes: some thoughts.

[EDG]

Using thruster plates you should be able to make some pretty decently quick normal-space interstellar probes. Send a fleet of them in a search pattern in the general direction of the target system and detect useful brown dwarfs by measuring their gravitational effect on the relative positions of the fleet of probes. Sure it'll take decades, but it'll get the job done.

I'm not sure you realise how huge a cubic parsec of space is, or how tiny a brown dwarf and its noticeable gravitational influence is by comparison. One cubic parsec of volume is about 8,780,000,000,000,000 cubic AU. Your average Brown Dwarf, on the other hand, is 0.0004 AU in radius, or a volume of 0.00000000027 cubic AU. And a rocky planet is about a tenth of that radius. Heck, our entire solar system's volume (assuming a spherical volume of 40 AU radius) is 268,082 cubic AU, which is still about 100 billion times smaller than the volume of a cubic parsec.

Still think it'll be easy to find?

 

[captainjack23]

I think at this point we can stop discussing ways to find the damn rogues and agree that it is very difficult, but not impossible, okay ? It can't be impossible unless we want to assume the terra jump point is a galactic oddity; and if so, then we've documented that the Vilanii need somthing - in at least eight hexes, to get to four of the six planets we know for sure that they visited before tl 12. If its difficult, even very difficult, its just a matter of resolve, and some luck. does that work ?
I'd say more and use less runon typing but I'm having some annoying keeps me away from the internet problems this evening. no it isn't called kids ho ho. more to come in any case as I can do so.

 

[EDG]

I think at this point we can stop discussing ways to find the damn rogues and agree that it is very difficult, but not impossible, okay ? It can't be impossible unless we want to assume the terra jump point is a galactic oddity; and if so, then we've documented that the Vilanii need somthing - in at least eight hexes, to get to four of the six planets we know for sure that they visited before tl 12. If its difficult, even very difficult, its just a matter of resolve, and some luck. does that work ?

Which is what I've been saying all along (though less resolve - more resolution, maybe ;-) - and more luck). I'm glad that finally sunk in...

As for the Vilani, well, they have eight hexes with known jump points, so they probably looked in a lot more and only found jump points in those eight. Of course, once they found the one they needed to cross the gap they had no reason to continue to waste time, effort and resources looking in the surrounding empty hexes for others. And when J2 was discovered those jump points became irrelevant anyway.

 

[captainjack23]

I think at this point we can stop discussing ways to find the damn rogues and agree that it is very difficult, but not impossible, okay ? snip

Which is what I've been saying all along (though less resolve - more resolution, maybe ;-) - and more luck). I'm glad that finally sunk in...

Glad you feel vindicated. Now that we are back to where we started, and discussion of finding them is allowed....

[/quote]

As for the Vilani, well, they have eight hexes with known jump points, so they probably looked in a lot more and only found jump points in those eight. Of course, once they found the one they needed to cross the gap they had no reason to continue to waste time, effort and resources looking in the surrounding empty hexes for others. And when J2 was discovered those jump points became irrelevant anyway.[/quote]


Actually, a bit more work before bed confirmed about seven more situations that need empty or dark body jumps...Azanti, luriani, and get this, the Syleans. Plus, the Genoee and the Azanti actually need two jumps to gt there, and the genoee needed one to reach their main allied race. five .Theres a big old firebreak which cuts off half of Zarushagar and Lishun sectors as well as others that isolate most of Dagudashag and Atnares and Core sectors. So a minimum of one per area that we know they were in, for say -four more ? And they probably had them in more places*, but one can only utterly be sure of one per barrier.

So, nine more points, that's seventeen, at an absolute minimum.

Damn things are everywhere -well, okay, at least four per sector it looks like. All unmarked, all traversed for centuries, and in some cases millenia; All right where they needed to be at the closest point possible. For at least half of the recorded contacts and or destinations.

And, I hastily note, i haven't even started on the nonhuman races. Nor am i gonna.

The way stars are distributed in the OTU, it becomes a stat question: how many one step jumps are possible before one meets a gap; coupled with how often will groups of stars be separated by contiguous chains of empty hexes. In fact, I'm pretty sure one could solve it with a good lisrel or marcov pattern , but I ain't gonna do that either; far too much like real work. Fact is the useful answer seems to be that the further you get from any start point, the liklihood increases tremendously. Any location randomly chosen about a half a sector away is likely to have one or more barriers to J1 traffic. And so far, the main vehicle we have are the dark bodies, which as we are told are VERY hard to find, almost impossible and requiring more than a little luck, even at tech 15, so much harder , and more luck (I assume) at tech 9.

But if they are used, they look to be all over the place....the heck ?

Maybe, just maybe, the gravity anchor thing is the piece of disinformation....not the coverup of all the vital trade links.

More commentary to come.....



* Why ? well, once one starts counting jumps, in many of the previous mainworld paths, and all of the paths that involve the big sector level barriers, it would take longer, in may cases several times longer, to jump around to get to the calibration point, then on to the world in question thn to just go thru the gab at sublight (two weeks per jump over a long series of jumps is really hustling it....).

 

[DPSteve]

I'm going to move slightly away from the debate of whether or not empty-hex jumps are or should be common, and go back towards how to make them.

Part of the underlying issue comes from not knowing what is needed to make jump calculations. If we assume that it requires some form of gravity well (which was not, apparently, part of the initial incarnations of Traveller) then this begs the question: black holes.

Black holes (collapsed stars for the layman) have enormous gravity associated with them. I imagine finding the gravity well of a black hole is somewhat easier than finding a floating rock or a brown dwarf; in theory they are also more plentiful then BDs.

What would the disadvantages be to using a black hole? I imagine that having a diameter measured in pin heads would make the 100 diameter percipitation point unhealthily close to the sucker. This would mean a lot of extra work to try and be SURE to jump well outside the 100 diameter mark.

Additionally, such a large gravity well in the area could possibly increase the likelihood of a misjump, both to and from the point.

However, if someone could get the jump right and eventually set up an outpost outside of the gravity well, then you would have a VERY defensible position (albeit a dangerous one) . . . hmm, and now I have an adventure to write, excuse me

 

[captainjack23]

I'm going to move slightly away from the debate of whether or not empty-hex jumps are or should be common, and go back towards how to make them.

Its a good explanation, and certainly could add to the means available for bridging jump 1 gaps.....

For me though, the issue is this: If one allows such bridges, and if they are less than impossible to find, then enough of them will be found to significantly change the whole pattern of the OTU.*

So, given that the whole mass based jump is only referenced in GTIW (which by the way, I love), and is intended to solve a specific problem in the context of the IW period, I'm inclined to believe that that isn't a good solution, if applied generally*. While it solves a few issues, it opens far more. And given the frequency with which bridges seem to be needed, I am not at all sanguine about the "they were forgotten or supressed, every last one of them, every record, mention or map, and the evidence that leads to the conclusion that they mucst be usable is similalry supressed, by every race, ever, no matter how many times they fell back to the exact same situation. " argument to fix it by the IW period.

*yes, this is a retrenchment and clarification of my original point -some of those issues have been answered, or (sob) proven baseless

 

[EDG]

Well the point is that in and before the IW era, you need a mass to jump to in the destination hex.

The obvious example of that is the Brown Dwarf/rogue planet. But as we've established, they're hard to detect.

Another example that I raised for the Geonee is that you just tow an appropriate mass out there. Anything with a lot of mass has a 100D limit, which includes kilometre-scale asteroids. So you take one from your belt, stick thrusters on it, and send it out into the empty hex on an accelerate/turnaround/decelerate path. When it arrives at where you want it, you turn off the drives and you now have a astronomical-scale body in your empty hex whose position relative to the surrounding stars you'll know, so that's something you can jump to.

And when you're done with it, you can turn off the beacons, send it flying off in a random direction, blow it up, or whatever.

There's no issue with making an artificial jump point. It can be done easily within canon (not sure of the timescales we're talking about to get it to a point a few lightyears away though, but at constant acceleration/deceleration and with enough fuel, we may be talking decades?) and it'll satisfy the "you need a mass at the other end" requirement.

 

[captainjack23]

Well the point is that in and before the IW era, you need a mass to jump to in the destination hex.
There's no issue with making an artificial jump point. It can be done easily within canon (not sure of the timescales we're talking about to get it to a point a few lightyears away though, but at constant acceleration/deceleration and with enough fuel, we may be talking decades?) and it'll satisfy the "you need a mass at the other end" requirement.

Which, I fear, is why I think that that part of GTIW isn't appropriate. Regardless of canonicity, or if it was mentioned anywhere else ever, or by who, answer this: If that is what it takes, why are there any gaps at all ?

A civilization that builds Tigress class ships, and uses masses from asteroid belts as hulls in other ships, and 1000 years of incentive, should have no problem linking over any gap, let alone the 1 hex gaps. Want to encourage trade ? Link mains - at least 50% of the imperial hulls are jump 1 IIRC. put down a chain of two or three, and J1 goes anywhere. Sure, J2 is cool and all, but now it too can go anywhere -faster !

Plus, and lets just stick with IW period, with jump 2 tech, one can use the exact same points to make J3 jumps; need a jump 3 gap crossed ? Move a planetoid into the hex next to the jump off, and poof ! Earth is splattered with H bombs in the Third War, but this time, by surprise ! And folowed by a fleet with a MUCH shorter logistic trail and information lag. By the third war, the Vilanii governor was both smart, non-traditional, had lots of time to prepare, and was quite willing to take the terran threat seriously.

In fact all the chokepoints can be avoided by use of this (or by finding the dark bodies) and all major Solar colonies become front line defenses. So, learning to say "please do not execute my brother, my family and indeed my whole homeworld ;as we would very much like to join the Empire " in Vilani will be earth's best defense.

So, no, I think at its heart, for these problems alone, the mass argument is a non-starter that causes more problems than it closes.

 

[EDG]

Which, I fear, is why I think that that part of GTIW isn't appropriate. Regardless of canonicity, or if it was mentioned anywhere else ever, or by who, answer this: If that is what it takes, why are there any gaps at all ?

Because it takes too much time and energy to haul things out there? And money. Someone's got to pay for doing all that.

But really, the problem is that if empty hex jumps are possible at all (whether or not you need a mass at both ends), then you're right - anyone can jump out to any distance, so long as they've got the fuel and jump capacity to do it. So why loop around a main for 10 parsecs when you can hop over a gap and get to your destination in one jump?

The oft-touted answer is that it comes at a great cost in cargo capacity (you need the extra fuel) and (again) is too much hassle to do, plus you're jumping twice and not making any money for two weeks instead of one.

So if that's out, then the next logical step is to ask what would happen if you needed stars at both ends (i.e. if you couldn't jump into an empty hex at all). In that case, we'd be stuck because the Terrans wouldn't be able to leave Sol until they invented J2 (which arguably wouldn't have changed much canonically) and the Vilani Imperium wouldn't have absorbed half its races because they needed J2 to reach them (which again probably wouldn't have really changed much, just changed a few dates).

So the intermediate step is "what if you just need a mass at both ends, that could be a planet or asteroid"? Then you have a way to allow limited access to the empty hexes, by having rare/hard to find astronomical bodies there or by towing planetoids out there to use as jump points. And those are easier to keep secret too, so access to them can be controlled and limited. And this arguably makes for a more interesting setting, where it's not a free-for-all and it's not totally constrained by stars.

So, no, I think at its heart, for these problems alone, the mass argument is a non-starter that causes more problems than it closes.

Only if you consider it easy to put those masses there. Technically it might be, but economically it probably isn't. If it was, then people would be doing it all the time, and they don't.

I'm not saying there aren't problems either way - there are. It's just that I think the 'middle ground' here causes the least number of them.

 

[far-trader]

I'll admit I stopped really paying attention after following this for a couple or so pages so I may have missed a point or two but as far as "rouges are there but very hard to find" and other questions perhaps my own TU take will work.

In my TU ALL jumps require a significant mass at each end. And it's very very difficult to find one that isn't associated with a star (i.e. "empty" hexes).

So how are empty hex jumps made? Almost always by accident, the first time. A misjump in my TU will always end at a significant mass, just not always a mapped one. So in the context of the 1st Imperium crossing gaps with J1 it was luck (good, bad, whatever). A ship misjumped (these were early jump drives, prone to misjump for using unrefined fuel) and instead of coming out at some star system lo they have stumbled on an interstellar dark body. A new jump point is added to the map! In an "empty" hex. And new territory previously inaccessible is now available. Or a shortcut is found. Some will jealously guard and keep secret these jump points. Some have been lost to knowledge through the ages. Others have apparently failed for some reason and attempts to jump to them result in a misjump (which in my TU all attempts to jump blind or to an unmapped empty hex will result in).

These points are rare, and some may even have been discovered but remain uncatalogued as the discoverers couldn't jump out. There are graveyards ala the (mythically exaggerated) Sargasso sea in my TU where ships have been ensnared by a dark mass but unable to escape for lack of fuel, and... other reasons... dark reasons...

 

[far-trader]

As for "building" a jump point in "empty" space. Sure it's possible. But the mass required is huge and the only way to get it there is by STL which takes a looong time. In my TU you simply can't jump there and maneuver drives are limited to operating at full efficiency in a significant gravity field.

 

[EDG]

But... let's see how hard it would be to tow a big rock into the middle of an empty hex anyway.

Let's say that the minimum size and mass required to be a jump point is a 1km diameter asteroid (assumed spherical) with density of 3000 kg/m3. So it has a radius of 500m, and it has a mass of about 1.6 trillion kg, or 1.6 billion metric tons.

Well that's a bit hefty already. And obviously off the scale when it comes to finding power plants and thrusters to move it from the book . But let's say that somehow you can fit enough of those (and fuel) to accelerate it at a constant acceleration of 1g halfway there, turn around, and decelerate by 1g to come to a relative stop in the middle of the empty hex 1 pc from your system.

So. One parsec = 3.08568e16 m. Half of that is 1.54284e16 m. So to travel half a parsec by accelerating at a constant rate of 10 m/s2, you just rearrange s=0.5a(t^2) (one of the basic equations of motion) to make t the subject.

And we find... huh.

It takes just 642.9271 days of accelerating constantly at 10 m/s2 to reach a distance of half a parsec. So to (instantly turnaround and) decelerate from there at the same rate, it takes the same time, so in total we're looking at about 1286 days to get a 1km asteroid out to 1pc.

All assuming that you can even move the damn thing and keep it accelerating that fast without it tearing apart. So in theory it'll take you about 3.5 years to get a rock out there... which isn't really that bad.

However, factor in the cost and effort of building the massive engines and power plants required to constantly accelerate the rock, and how long it'd even take to find an asteroid that isn't a rubble pile that will fall apart the moment it comes under any acceleration, and and how long it'll take to build those facilities in or on the asteroid and secure it all structurally, and so on... and you're getting something that will require a lot of time, effort, and expense to pull off. So while it won't take forever to get to its destination, it doesn't really look to me like it'll be something that can be done on a frequent basis.

So we're back to having rare, limited and controlled access to empty hexes, which works out just fine.


EDIT: Crap. As Vargr1 pointed out, it's going about twice the speed of light at the turnover point! And I'm buggered if I can calculate the relativistic effects as it approaches c, so I guess that rules out going at 1g acceleration!! :shock:

 

[far-trader]

Thanks EDG I was gonna tackle the math but really didn't feel like it

I'd have gone with 0.1g at the most but while that will save some on fuel(?) and machinery it's probably not much. And how long would that be if I can impose on your fresher calculating ability? Just mildly curious really, not dying of it by any stretch or I'd force my brain awake to do it

(and my 100th post here, woo hoo I'm a Mongoose :twisted: )

 

[zozotroll]

Welcome to the ranks young mongoose.

 

[GamerDude]

Ok, I'm trying to wrap my mind around something?

Where in all the Cannon is it stated that a mass is needed at the end point of the jump to plot it? Heck, where in the cannon is what is required at the end point of a jump?

I mean, don't give me GT:IW because, as EDG has stated... GT is an ATU and it's never been clarified where the GT time line split from the OTU time line, so IW has no bearing on the question.

Thanks in advance.

 

[far-trader]

It's not iirc. At least not explicitly. But neither is it explicitly stated that it isn't (again iirc).

My own take on it was decided long before there was much canon on the matter (at least in my library and knowledge). Probably before I got any of the supplements to LBB1-3.

The reason I decided that a mass was required to emerge from jump was the same as another poster mentioned in one of the many same threads on this here or on another board.

What happens when the players misjump to an "empty" hex? Sure I could just fudge it and say they don't and have them come out in one of the many mapped star systems. But that's a cheat. They take the chances of rolling those D6s they get what they deserve. Still nobody wants a campaign to end with a whimper in the cold empty of space. So I decided that there is some mass to drop them out. And give them a chance not only of living but of a great discovery. Something to drive the plot for many adventures.

I could not care less if someone, anyone, even MWM himself, then comes along and says "Hey, guess what, you CAN jump to empty hexes!"

Personally I think my way is both simpler and more internally logical than all the convoluted canon on it that has been invented over the years.

 

[EDG]

I mean, don't give me GT:IW because, as EDG has stated... GT is an ATU and it's never been clarified where the GT time line split from the OTU time line, so IW has no bearing on the question.

It has been clarified, by Loren Wiseman on the SJG boards (roughly. He's hinted at the date but not actually specified it). GT is officially an ATU after Dulinor gets blown up in his shuttle (and thus the Assassination never happens). But Loren has hinted that the actual divergence point is a few decades before that, but still in the late 1000s. Before that, the history is the same.

Either way, despite what Aramis said, GT:IW has not been declared to be an "alternate universe" by anyone.

 

[EDG]

Thanks EDG I was gonna tackle the math but really didn't feel like it

I'd have gone with 0.1g at the most but while that will save some on fuel(?) and machinery it's probably not much. And how long would that be if I can impose on your fresher calculating ability? Just mildly curious really, not dying of it by any stretch or I'd force my brain awake to do it

At 0.1g acceleration instead of 1g, you'd have to multiply the time taken by the square root of 10 (3.16).

So it'd take a total of about 11 years to tow that rock to the empty hex.

 

[vargr1]

It takes just 642.9271 days of accelerating constantly at 10 m/s2 to reach a distance of half a parsec. So to (instantly turnaround and) decelerate from there at the same rate, it takes the same time, so in total we're looking at about 1286 days to get a 1km asteroid out to 1pc.

You might want to check the velocity of that rock at turnover. I think the universe might have a problem with it.

 

[zozotroll]

And I want empty hex jumps for places for pirates to hide. And the Navy has to patrol. And who knows, could be a stray comet or two out there.

But both aproaches work. But I am clear to my players which way I go.