Scrunched Known Space

[Kilgs]

Many years ago there were a couple of threads about reducing the size of the Imperium to only a few sectors and thus having more of the surrounding polities available "in play" so to speak.

I thought I had started a thread on it, but it is likely it just came up in another. IIRC Rob did some maps of a reduced size Imperium.

To the search engine...

I absolutely swear I was NOT looking for this... Just scrolling through Reddit for gems like I do every few months. And here is some discussion of it and... possibly the thread you were thinking of?

Reddit: Collapsing Charted Space

And the 14yo thread they're referencing...
Great Minds Think Alike

 

[mike wightman]

That's the first time I have seen it - you will notice that the work that was done on the CotI boards pre-dates this lot by four years.

 

[Grav_Moped]

Screwing around with the jump formulas, diminishing returns for larger hull sizes, would make smaller starships, ahh, faster.

So, LBB2 then?

 

[robject]

I thought I had thrown it all away, but here's a bit of The Small Imperium map, that Mike was talking about.
This has to be from around 1997.
It's not the quadrant-based map that I had also fooled around with.

 

[Condottiere]

As I recall alphabet drives, there was room for min maxing.

 

[Kilgs]

Screwing around with the jump formulas, diminishing returns for larger hull sizes, would make smaller starships, ahh, faster.

Funny because I did the same thing in my first ATU but it didn't use Trav mechanics so can't replicate. I might have to pull out my old LBBs if thats the case.
---
On a related note, I was thinking about how to switch from jump-space to a different kind of drive and came up with a halfway decent explanation... I'm a Glimmerdrift/Crucis Margin fanboi so this has to do with that region but also 1248.

Deadspace.

I never really liked it but was thinking that maybe it kept expanding and showed no signs of stopping. For awhile, everything would get pretty quiet but then someone invents a new drive and yay! Why, you ask?
>Because no one figured out where JSpace was and why it was.
>Turns out one of the Precursor civilizations discovered this dimension with a particular quality of breaking time-space and harnessed it for their own usage. To do so required Dyson-sphere like structures built at varying interstellar distances to maintain the 'opening/availability' of the dimension.
>Unfortunately, no one knows this and those field-generator-thingies are actually within JSpace.
>Even worse, after 20,000 years, they're falling apart and losing power. As they do so, JSpace is released from the 'stable position' it was forced into for Jump travel and becomes inaccessible.

 

[Kilgs]

All right you fibbers, I scoured LBB2 and saw no variant rules or anything. What are you keeping away from me?

 

[Straybow]

3D space. An Imperium of 11,000 star systems could fit within a 27 pc radius.

 

[Grav_Moped]

All right you fibbers, I scoured LBB2 and saw no variant rules or anything. What are you keeping away from me?

I only mentioned LBB2 for the Drive Performance Table and its tradeoff between size and speed (with higher TL allowing more of both until hitting the wall at 5 kilotons -- or 10-12 kilotons if you extrapolate a bit).

 

[Condottiere]

Subgee, if you're not in a hurry.

Jump factor/zero, at twenty four kilotonnes.

 

[Grav_Moped]

until hitting the wall at 5 kilotons -- or 10-12 kilotons if you extrapolate a bit

5KTd is the limit of the table.
10KTd is potential 1, extrapolated from potential 2 for a Size Z drive in a 5KTd hull.
12KTd is potential 1, extrapolated from potential 3 for a Size Z drive in a 4KTd hull (or 6 in a 2KTd hull).

LBB2 doesn't do fractional-factor or factor-0 drives, it just has dashes in the table indicating that "it doesn't work"*.

Other rule sets might handle things differently. IIRC, in T5 jump ratings below 1 simply don't work at all -- though a Jump-1 drive can do a Jump-0 (up to 1 parsec) if it's not TL-limited to exclusively 1-parsec jumps.


---------------
*I'd house-rule that if you're using LBB2 drives in a "LBB2 + LBB5" universe (AKA a LBB5 universe), LBB2 power plants can have ratings above 6 (possibly including mixed numbers or their decimal approximations**), but this would require calculating and tracking the ship's energy points under LBB5 rules. This gets problematic for the TL-15 (Size W-Z) power plants since their performance -- unlike the rest of the LBB2 drives -- was set arbitrarily.

** such as Pn-6 1/3 (AKA Pn-6.33). And yes, I just added a footnote to a footnote.

 

[aramis]

3D space. An Imperium of 11,000 star systems could fit within a 27 pc radius.

V=r³π4/3
r=23, r³=19683, using π=3.1415
V= 19683 * 3.1415 * 4/3
V =82,445.526 Pc³

It's worth noting that the 50% base odds (Bk3-81 p.4) per parsec, the average separation would be about 1.5 Pc; accounting for the 70% packing maximum, about 40,000 systems... Also, 5 LY is about the average IRL¹.

27 Pc is WAY too big.
11000, assume modal separation of 0.75 Pc, for 1.767 Pc³ per system. the ÷0.705 for packing efficiency for 2.507 Pc³.
So multiplying per system, 27571.676 Pc ... 19 Pc radius is sufficient.
20-22 Pc more realistic... 33,500 Pc³ to 44,600 Pc³.

Especially since 95% of the mapped space in the OTU is accessible with merely J2.

-=-=-=-=-=-=-=-=-​

¹: https://public.nrao.edu/ask/what-is-the-average-distance-between-stars-in-our-galaxy/

 

[coliver988]

well, technically, 20-22 Pc fits in 27 Pc...

the one time I played with doing 3D space was short-lived: while the mapping program was really cool, it was not something readily available at the table (and we were at a table then!) and I really like maps that I can use without technology (aka, print out). I still stick with the idea that the 2D maps are mere representations of 3D space for jump purposes and may not necessarily map 1:1 with the actual universe. Like a subway map, it shows the stops and distances and is usually not reflective of actual terrain.

but back to the topic: there have been several good suggestions in this thread for "shrinking" space to give more access to other species. I'm enjoying the topic.

 

[willtron3030]

V=r³π4/3
r=23, r³=19683, using π=3.1415
V= 19683 * 3.1415 * 4/3
V =82,445.526 Pc³

It's worth noting that the 50% base odds (Bk3-81 p.4) per parsec, the average separation would be about 1.5 Pc; accounting for the 70% packing maximum, about 40,000 systems... Also, 5 LY is about the average IRL¹.

27 Pc is WAY too big.
11000, assume modal separation of 0.75 Pc, for 1.767 Pc³ per system. the ÷0.705 for packing efficiency for 2.507 Pc³.
So multiplying per system, 27571.676 Pc ... 19 Pc radius is sufficient.
20-22 Pc more realistic... 33,500 Pc³ to 44,600 Pc³.

Especially since 95% of the mapped space in the OTU is accessible with merely J2.

-=-=-=-=-=-=-=-=-​

¹: https://public.nrao.edu/ask/what-is-the-average-distance-between-stars-in-our-galaxy/

Thanks for taking a legal-sized page of my scribbling, and expressing it in four lines and a paragraph... I guess the journey was still worth it.

I've been messing with a face-centered cubic (FCC) arrangement of 1pc (well, 1.0E8 light seconds, ~0.95pc) diameter spheres, and putting systems in about 15% of them, and could fit 40k systems into a sphere ~35pc radius.

 

[aramis]

Thanks for taking a legal-sized page of my scribbling, and expressing it in four lines and a paragraph... I guess the journey was still worth it.

I've been messing with a face-centered cubic (FCC) arrangement of 1pc (well, 1.0E8 light seconds, ~0.95pc) diameter spheres, and putting systems in about 15% of them, and could fit 40k systems into a sphere ~35pc radius.

Checking each other's math is usually a good thing.
Checking each other's process is also usually a good thing.

 

[Straybow]

V=r³π4/3
r=23, r³=19683, using π=3.1415
V= 19683 * 3.1415 * 4/3
V =82,445.526 Pc³

It's worth noting that the 50% base odds (Bk3-81 p.4) per parsec, the average separation would be about 1.5 Pc; accounting for the 70% packing maximum, about 40,000 systems... Also, 5 LY is about the average IRL¹.

27 Pc is WAY too big.
11000, assume modal separation of 0.75 Pc, for 1.767 Pc³ per system. the ÷0.705 for packing efficiency for 2.507 Pc³.
So multiplying per system, 27571.676 Pc ... 19 Pc radius is sufficient.
20-22 Pc more realistic... 33,500 Pc³ to 44,600 Pc³.

Especially since 95% of the mapped space in the OTU is accessible with merely J2.

-=-=-=-=-=-=-=-=-​

¹: https://public.nrao.edu/ask/what-is-the-average-distance-between-stars-in-our-galaxy/

Your stellar density is way too high.
Actual stellar surveys (could have changed slightly since 2020 when I was researching this)

Radius Pc	Observed Stars	Stars/Pc³	Notes
5	63	0.120	Comprehensive; high confidence
10	347	0.078	Survey incomplete
15	1008	0.071	Survey incomplete
20	2127	0.063	Majority of dim stars undetected
25	3496	0.053	Most dim stars undetected

If we suppose the initial 0.120 stars/pc³ = 8 pc³ per star to be typical, it would look somewhat like this:

Radius Pc	Stellar Systems	Stellar Objects
5	64	80
10	512	640
15	1728	2160
20	4096	5120
25	8000	10,000
30	13,824	17,280

Stellar objects includes brown dwarfs, white dwarfs, and other oddities that might not constitute "stars." So far there are 48 brown dwarfs and 21 white dwarfs within 10 pc, compared to 347 known bright stars. These are nice, round numbers to make the math easy.

I can't seem to make the columns the way I want...

 

[tjoneslo]

My thought for this was to combine two campaign running ideas into one. One is, obviously, this one where the Imperium is packed into a 3D sphere of stars and the surrounding empires are crowding in close.

The second was to limit the play area to a subsector sized area. The campaign takes place between 20 or 30 worlds. And this can be rendered in a flat map handed out to the players . Yes there are additional stars in every direction that may be part of one empire or another. And the capital is only a few jumps in that direction, and the Zhodani are four jumps in that direction.

 

[Straybow]

To be specific, where that chart says "survey incomplete" or "dim stars undetected," those stars probably can be seen in photographs, but their positions haven't been determined accurately enough to count within the 25 pc of the surveys.

 

[aramis]

Your stellar density is way too high.

Taken from NASA sources on average stellar separation.

I can't seem to make the columns the way I want...

There's no provision for aligning across multiple cells; you can set the paragraph alignment cell by cell...

 

[Kakistocrat]

Actual stellar surveys (could have changed slightly since 2020 when I was researching this):

Radius (pc)	Observed Stars	Stars/pc³	Notes
5	63	0.120	Comprehensive; high confidence
10	347	0.078	Survey incomplete
15	1008	0.071	Survey incomplete
20	2127	0.063	Majority of dim stars undetected
25	3496	0.053	Most dim stars undetected

The Gaia Catalogue of Nearby Stars (GCNS) from the Gaia Early Data Release 3 (EDR3) gave an estimate of 331,312 objects (with Gaia’s nominal magnitude detection limit of +20.7) within 100 pc of Sol that have measured parallaxes ϖ̂ > 8 mas (“M8”). This sphere has an estimated mean density of 0.081±0.003 main sequence stars per pc³. To quote from the paper’s conclusion,

This is an increase of an order of magnitude with respect to the most complete nearby star census prior to the Gaia mission. A comparison with Gaia DR2 shows that the last release contained more contamination than Gaia EDR3, but also that a few percent of real objects are still not included in Gaia EDR3. The overall completeness of the GCNS to M8 at 100 pc is probably better than 95%. An examination of the 10 pc sample finds that we provide the first direct parallax of five stars in multiple systems.​

(The “10 pc sample” refers to a sphere around Sol with a 10 pc radius which was used as a data consistency check on the 100 pc data set.)