The Universe is not flat!!!

[Maspy]

So fellow Travellers, what is your take on this:

http://www.nbos.com/products/astro/astro.htm

This looks very kewl. What is your take on 3d mapping? Worth it or no, for gaming?

 

[Elliot]

IMTU the traveller map is a represenation of jump space not real space - they vaguely correspond but not fully - hence some real stars maybe farther away on the map than 1 (jump) parsec.

I admit its a fudge - but it keeps things simple

 

[savage]

I agree with Elliot in that the Z axis does not need representation.

other discussions have attempted to define the known universe in 3D terms. Everything Ive seen in 3d is great for small game environments. As I recall 11,000 stars of the Imperium becomes 400,000. Unless one takes the stance that only stars with planets are on the map...Either way its a tough nut to crack.

Savage

 

[robject]

"Officially" (which only means 'an explanation for the intended feel of the game') the flat map represents realspace, more or less. A sublight sleeper colony ship could set a course using the hexmaps.

There's no reason the map can't be a little bumpy, though, or even a warped, wobbly plane. 3 light years gives a little bit of wiggle room.

Moreover, it might be possible, with a small amount of 'canon slippage', to contort the plane around on itself into a pseudo-3D shape. A guideline might be that neighboring stars must nearly always maintain their correct distances apart, and that distant stars must remain distant, although with more wiggle room than the neighboring stars. A star that's 20 parsecs away on the flat map could probably be only 15 parsecs away in 3D distance, just as long as the actual jump route to it remains longer. A certain amount of bending is probably acceptable.

 

[BetterThanLife]

Actually given the size of the Imperium, or better yet the size of "known space." The Galaxy is fairly flat. Our Solar System can be fairly well represented in 2 dimensions. Most stars are on or very close to the Ecliptic. (IN the solar system most of the bodies in the system are right on the ecliptic. Once you are at the center of the Galaxy it appears to be more globular but in the region maped it is relatively flat. Our galaxy is like a disc. It isn't like a piece of paper but it isn't all that thick compared to the radius of the disc.

 

[Malenfant]

I feel obliged to point out my 3D mapping page for the stars near Sol

Oh, and most stars are actually nowhere near the ecliptic. In fact, the important thing is the stars' Galactic Co-ordinates, not the ecliptic (which is defined solely by the Earth's orbit around Sol). Antares, for example, is actually 177 pc coreward of Sol, 25 pc to trailing, and 48 parsecs 'above' Sol, which is itself about 50 pc above the actual galactic plane. Some of the nearby stars in Ursa Major (eg Mizar, Alcor) are 22 pc above Sol.

As you go further from Sol, stars are actually more likely to deviate greatly in terms of vertical distance from Sol's 'layer'. Which makes sense - a star 400 pc away on the galactic equator may be on the same layer as Sol, but if it's even a small amount above or below that then that will translate into a large deviation given the distance. Given that stars are in fact located all over the sky and aren't concentrated near the galactic equator (i.e. the galactic plane, roughly), many stars will be quite far from it.

 

[BetterThanLife]

I appologize about the improper use of the term ecliptic. I meant the Galatic equivalent of the Eciptic. Now the farther they are away from SOL the more Z axis seperation you are likely to see? You can't go that far in a single trip. (Not in Traveller anyway.) For game mechanics the Flat along the plane of the Galaxy model works out fine. We aren't only talking about the area in our neighborhood. Matter of fact using jump 6 couriers it takes 7 months toget from Regina/Spinward Marches to Capital/Core and an additional 6 and one half months from Capital/Core to Terra/Solomani Rim. (Source "Rebellion Sourcebook") On that scale a little vertical seperation has no real effect.

The X-Boat network would take over a year and a half to send a message from one to the other. Since we are dealing with short distances within a large disc structure then using a flat map is more than sufficiently accurate. (Especially since we don't really know how jump drive works.

)

I am not saying that there are stars above and below the Galatic plane. Most of the systems are along the plane though. And the closer you get Coreward the closer to the plane they are likely to be.

I do not doubt your model is accurate. I also realize that nothing is truly flat. (Not even Kansas.) However that doesn't mean it isn't relatively flat.

Originally posted by Malenfant:
I feel obliged to point out my 3D mapping page for the stars near Sol

Oh, and most stars are actually nowhere near the ecliptic. In fact, the important thing is the stars' Galactic Co-ordinates, not the ecliptic (which is defined solely by the Earth's orbit around Sol). Antares, for example, is actually 177 pc coreward of Sol, 25 pc to trailing, and 48 parsecs 'above' Sol, which is itself about 50 pc above the actual galactic plane. Some of the nearby stars in Ursa Major (eg Mizar, Alcor) are 22 pc above Sol.

As you go further from Sol, stars are actually more likely to deviate greatly in terms of vertical distance from Sol's 'layer'. Which makes sense - a star 400 pc away on the galactic equator may be on the same layer as Sol, but if it's even a small amount above or below that then that will translate into a large deviation given the distance. Given that stars are in fact located all over the sky and aren't concentrated near the galactic equator (i.e. the galactic plane, roughly), many stars will be quite far from it.

 

[Malenfant]

Depends what you define as 'flat'. The disk extends for a minimum of several hundred parsecs (probably more) at least above and below Sol. Obviously, we have nearby and mid-distance stars that are directly above Sol and can still be in the disk. It's true that the more distant stars that we see can't be right above us and still be considered to be in the disk though, so they're closer to the galactic equator (I presume that's what you meant when you said 'ecliptic').

I've recently been wondering if an "arms and fingers" arrangement wouldn't be better for a more realistic/3D Traveller. Right now, there are far too many useless/low tech/no starport planets that are way off the spacelanes in the OTU for my tastes. I don't like the 'amorphous blob' shape of the Imperium (or indeed any of the major polities in Charted Space) in this context - I could, however, imagine a long, heavily travelled chain of core systems between say Terra and Antares that had a few fingers going off it for short distances, and another arm branching off towards the Spinward Marches from Capital or thereabouts.

 

[BetterThanLife]

Kansas and Indiana both have hills but nobody in either state will admit to them. And they are absolutely tables compared to the states along the Rockies or even the Applachians.

The thickness of the disk compared to the radius of it is relatively small. Which was my point. ANd since "Known Space" goes quite a distance from the Coreward end to the Rimward end and from the Spinward end to the trailing end it would appear fairly flat, even though local conditions may vary considerably.

As far as realism within the OTU and relative tech of worlds. Given the economics of travelling around, the only profitable way to purchase a merchant on credit is to buy a jump 1 merchant. (there are of course exceptions.) The technology should be higher and centered along the various "Mains" with anything off the Main being more of a backwater. Yet along the Spinward Main tech level only hits 15 at Glisten. (The far end of the Spinward Main) And all the other High Tech worlds, are off the Main.

Go figure.

 

[Malenfant]

Originally posted by Bhoins:
The thickness of the disk compared to the radius of it is relatively small. Which was my point. ANd since "Known Space" goes quite a distance from the Coreward end to the Rimward end and from the Spinward end to the trailing end it would appear fairly flat, even though local conditions may vary considerably.

Sure. But there's still at least a 110pc difference between the "highest" and "lowest" stars across Charted space (Spica is 62pc above Sol, for example), so one could assume that the Imperium would be at least that thick in practice. Yes, you probably won't notice that if you're only going from star to star in 2pc jumps, but that doesn't mean that the imperium is particularly 'flat' on a large scale.

 

[BetterThanLife]

The distance from The Solomani Rim Sector to the Vargr Border is about 200 Parsecs. (Straight line) Known space looks a bit farther Spinward to Trailing. Antares to Regina is about the same distance. 55 Parsecs +/- from the center isn't that far, though it is farther than I thought it would be.

"Known Space" is 320 parsecs Rimward to Coreward. About 510 Parsecs Spinward to Trailing. (Yes I just did the math.) Since most players stay in their own little pond.

I have yet to see anyone really try to go from Regina to Terra. The farthest I have ever seen a party go was Ryhlanor/Spinward Marches to Depot/Gushemege. We never did finsih the round trip.

It was a suggested mission from the Rebellion Sourcebook. That is only crossing two sectors. (Well it takes longer since you really can't cross Reft sector without a Jump 6 ship and permission to use the "Secret Naval Fuel Dump" provided you could find out where it actually was.

There is obvious distance between top and bottom of the disk, for the sake of simplicity though in the Grand Scheme of things it is reasonable to use a flat map. (Especially since holographics aren't available in a book at this Tech Level.

Though I am still waiting for my first Air/Raft, and man portable laser weapon.

 

[Malenfant]

Well, one could assume that Charted Space consists of stars that are within +/- 6pc (vertically) of Sol. But then you'd have to ask why nobody's gone beyond that height when there are obviously zillions of stars there, and you'd also have to get rid of just about every named star on the maps that are beyond about a 6 pc diameter of Sol.

Obviously, it IS a lot simpler to use a flat map of a 2D universe - I'm not saying it isn't. I'm just pointing out how things would be if the OTU was actually realistic and 3D.

 

[Drakon]

The reason why we use a flat map is actually quite simple. 3D on paper is too hard. It does not add to game play, its "close enough" to be somewhat realistic, and you simply can't do 3D well on a 2D surface of paper.

The NBOS software that Maspy linked is very cool. And with the pervasiveness of laptop computers, might not be much of problem to integrate a 3D map into games. If it performs as advertised when released, one can zoom, scan, or rotate the 3D map any way one likes. It will also compute distances automatically.

Using Bhoin's numbers, that means that known space is 1662.6 lightyears Spinward to Trailing, and 1043.2 lightyears Rimward to Coreward. But the disk out where we are at (28,000 lt yrs from the galactic core) is 2,000 lt yrs thick! The disk in this region of space is thicker than the OTU known universe!

[Couple additional astronomy facts. 1) the Orion Arm, where Sol is located, is about half way down the arm, along the inner (Coreward) edge. The arm is reported to be about 3,500 lt yrs across. Rimward of this arm is the Perseus Arm, and Sagittarius Arm is Coreward. Apparently the arms go, from Coreward to Rim, Norma (or 3kpc), Scutum-Crux (or Centaurus), Sagittarius (Sagittarius-Carina), Orion (or Local), Perseus, and Cygnus (or Outer) in a barred spiral shape.]

 

[BetterThanLife]

Hey I am just using the map of "Known Space" from The Library Suplements.

I may be off by a couple of parsecs.

The other numbers came from the maps showing how long it took news of the assassination in the Rebellion Sourcebook. I certainly don't have "Known Space" charted. (Though that would be a cool thing to do.) With the power of modern personal computers one could easily create a spreadsheet to map the entire region.

Just using the formulas from Book 6 or the transferred ones in THB and you are all set. Of course doing things that way no two maps will be the same. There is a map in MT that shows where all the stars are and you can interpret distances fairly well. Perhaps scanning this in for your location of stars and going from there. YOu would also have to scan in the charted and published areas, (Spinward Marches, Gateway Domain, Solomani Rim....

)

What is the "Second Survey" book on FFE's website?

 

[TKalbfus]

What's wrong with an Imperium of 400,000 stars? Presumably your were not going to map all 11,000 stars anyway. Just map a few key subsectors or even a sector. That's plenty of stars! If the player wants to go outside the detailed map, you can provide him with a general overal map showing only the most important stars, and generate a corrodor of subsectors leading to the players destination generating only random worlds encountered on the way.

 

[Malenfant]

Originally posted by Bhoins:
"Known Space" is 320 parsecs Rimward to Coreward. About 510 Parsecs Spinward to Trailing. (Yes I just did the math.)

It's actually about 444 parsecs Spinward to Trailing. A subsector is 8 pc wide only if you zig-zag up and down across the hex columns - if you go straight across, it's actually just under 7 pc wide, since the horizontal distance between the hex columns is 0.866 pc.

So each sector is really about 28 pc wide (not 32), and the total width of the 16 sectors of Charted Space is 443.4 pc.

Using Bhoin's numbers, that means that known space is 1662.6 lightyears Spinward to Trailing, and 1043.2 lightyears Rimward to Coreward. But the disk out where we are at (28,000 lt yrs from the galactic core) is 2,000 lt yrs thick! The disk in this region of space is thicker than the OTU known universe!

(Spinward to Trailing width is 1445.5 pc, with my corrected numbers)

EDIT: Never mind, I misread, sorry. Yes, the disk here is thicker than the OTU.

 

[Straybow]

Kinda hard to imagine maintaining any control in the 11,000 star OTU. How much hand-waving in a 400,000 star 3D region?

 

[Malenfant]

Well, if you have a 3D universe, I think teh borders of the empires get a lot tighter - a 100pc radius sphere would have a hell of a lot of stars in it. Either that, or the empire would be set up as chains of worlds (ie. arms/fingers), and any world not on a jump route would be ignored.

 

[RandyT0001]

Using the assumed average of one system per two cubic parsecs, a 100pc radius sphere would have about 2 million stars.

Using the same assumed average as above, then 11,000 star systems would occupy a sphere with a radius of about 18pc.

Using a 'realistic' 3D map means that there are probably not going to be any occurances of jump-5 and jump-6 rifts like in the OTU. In a spherical Imperium of 200pc in diameter then your jump-4 ships (average jump capability for many Imperial Navy capital and cruiser ships) could travel from one border to the one across the Imperium in a little over a year's time. I think that the jump capability of Traveller games which utilize 3D real-space data to plot system positions maybe should be limited to jump-1 for PC traders and scouts (scouts have fuel enough for two jump-1's), jump-2 for mega-corporation liners and merchant ships and jump-3 for Naval ships.

Maybe my number of systems in the 100pc radius sphere are wrong. That is alot of systems to have to generate.

 

[Malenfant]

I suspect your numbers might be a little bit off - the Hipparcos star catalogue lists only about 771 stars within 18pc of Sol. It's probably not picking up all the M V stars though, but I'd guess there's probably more like 2 or 3,000 stars within 18pc of Sol at most.