Stellar Cartography in a 2d universe

[sudnadja]

While working on several approaches in an attempt to map 3d stars into 2d charted space, I noticed something: there are large volumes of space close to the sun that are unreachable without high jump (>2) drives. From the Sun away from the core and at positive angle +z, there's really nowhere to jump to. (The attached plot is opacity and color coded for point distance to the nearest star. Opaque Orange spaces are the furthest away (most inaccessible).



I know that the 3d vs 2d discussion about Traveller has been going on for ages, and by and large it seems that most Traveller players prefer 2d. To me, the 3d map makes the universe feel much more vast, even when looking on close in spaces:


Barnard's Star doesn't seem crowded in by a bunch of other stars, like it kind of does (to me) on the 2d map.

In Traveller canon, Junction (Wolf 359) has two stars that can be reached by Jump-1 and in reality, no stars can be reached from Wolf 359 with Jump-1 (Lalande 21185/Midway is 1.25 parsec away).

I'm sure this has all been talked about many times before - is there an ongoing megathread about it somewhere?

Anyway, my question:

In canon, can starships jump into empty space? Interstellar Wars (is that canon?) implied that they cannot, a jump point - some kind of massive body in interstellar space - has to be identified to jump to and then make a further jump to get to a destination. I believe that it mentioned that the first flight to Barnard's Star was done in this way.

 

[mike wightman]

Canon answer -
Originally CT had empty hex jumps, they are featured in several adventures, but there was a fly in the ointment.
The board games Imperium and later Dark Nebula only allowed jump between systems, not into empty hexes (although in DN a research project can grant your fleets empty hex jump capability). Some argued that historical settings for the OTU should preclude empty hex jumping because of this.

In GT ISW - ships could only jump from system to system, no empty hex jumps, the reason cited was the maths of empty hex jumps was beyond Vilani or Terran science Ties in with Imperium and Dark Nebula).

It would be centuries before the discovery of the maths that allows for empty hex jumps (which ties in with Dark Nebula research project).

By the time of the founding of the Third Imperium empty hex jumps have been a thing for centuries.

 

[aramis]

[m;]When posting large images, please use the IMGW= tag in place of the IMG tag[/m;]
Many of us don't have huge screens, and it makes it awkward to read the thread, too, if the image makes it overwide. (I edited it for you this time).

Back On Topic. Interesting.
Last set of calculations Marc asked me to run were OTU as 2D plane through 3D space... so... you may be on to something Sudnadja.

 

[Thot]

My upcoming campaign uses a 3D map with a cube roster, but for the OTU, I came up with an in-universe explanation for why they use 3D maps and why many stars are missing from the map: There is a "jump space structure" in normal space that looks like a crumpled table cloth and only makes those stars accessible that the maps show. Any stars that are not touched by this mysterious energy field are only accessible via STL.

It's not perfect, but it does work.

 

[estar]

I think a link map is a suitable compromise between 2D and 3D maps. Real world stellar cartography function more or less as a link, cluster, branch subway style system of routes.

For example this map from The Project Rho Website.
http://www.projectrho.com/public_html/starmaps/media/winchhabhyg/HabHYG30lyNode.png

 

[sudnadja]

I think a link map is a suitable compromise between 2D and 3D maps. Real world stellar cartography function more or less as a link, cluster, branch subway style system of routes.

For example this map from The Project Rho Website.
http://www.projectrho.com/public_html/starmaps/media/winchhabhyg/HabHYG30lyNode.png

To be honest, maps might not be as useful as just 3d position vectors, which are in a more appropriate format for rotation and transformation than a map is anyway, and then players are faced with the same problem that real world astronomers are - how to make sense of that mass of data.

One thing that link maps don't do particularly well is illustrated by the interstellar wars described first jump from Sol to Barnard's Star - a wandering planet or brown dwarf had to be found between Sol and Barnard's Star that was reachable by Jump-1 from either. Another interesting question then is: is there a volume of space which is reachable by Jump-1 from all Sol, Alpha Centauri, and Barnard's Star? (the answer is no, but just barely no) A link map can't tell you that easily, but it's something that would occurs as a question to astronomy minded player characters.

 

[kilemall]

IMTU empty space jumps are possible, no gravitic anchor or the like necessary.

Conveniently, what we have Out There is the Oort Cloud. So ice-based refueling stations have sprung up, that enables 2 jumps out of Terra.

As a result, there are many many fueling stations, including the most famous, Faust Vegas.

When J-2 is 'discovered', most of these places will become like bypassed gas/motel towns on Route 66 when the interstates went in.

 

[sudnadja]

IMTU empty space jumps are possible, no gravitic anchor or the like necessary.

Conveniently, what we have Out There is the Oort Cloud. So ice-based refueling stations have sprung up, that enables 2 jumps out of Terra.

Oort Cloud objects extend out to perhaps 1 light year from the sun, so a jump to one of those more distant object would still leave 1.51 parsec or so to jump on to get to Barnard's Star.

Alpha Centauri is even too far, 1.039 parsec remain from Sol's outer most Oort Cloud (presuming it extends as far as a light year). Interestingly, Proxima Centauri is just barely inside that, 0.98 parsec remain. So Jump-1 is workable in that context, Earth->Sol Oort cloud for fueling->Proxima for fueling->Alpha Centauri A/B

 

[mike wightman]

The Oort cloud remains entirely hypothetical, there is no observational evidence to confirm or deny its existence.

 

[sudnadja]

The Oort cloud remains entirely hypothetical, there is no observational evidence to confirm or deny its existence.

I think we're using Oort Cloud as shorthand for "Icy objects with aphelions >5000 AU", of which at least a few are known. There are comets with two-body aphelions out into the light years, and even given the nbody solution bringing that down closer to 5000-10000 AU, the difference in velocity that would bump out those aphelions into the dozens of AU would lead me to believe that there are probably some comets with higher aphelions than the ~5k-10k AU currently known.

Though it's pretty unlikely that, even if there are, they're able to be discovered out that far.

 

[Ulsyus]

I think a link map is a suitable compromise between 2D and 3D maps. Real world stellar cartography function more or less as a link, cluster, branch subway style system of routes.

This brings to mind the stellar mapping and travel that was done in 2300AD. It's great if travel has to be from one star to another in the links, but if advances allow for greater distances to be travelled then it loses its luster as it's quite difficult to determine new distances from something like this.

 

[sudnadja]

The Oort cloud remains entirely hypothetical, there is no observational evidence to confirm or deny its existence.

For context, plots (presumably 2-body) of several long period comets ( C/2012 CH17 (MOSS),C/2014 XB8 (PANSTARRS),C/2000 W1 (Utsunomiya-Jones),C/2012 S4 (PANSTARRS),C/2000 O1 (Koehn),C/1992 J1 (Spacewatch),C/1937 N1 (Finsler),C/1972 X1 (Araya),C/2014 S1 (PANSTARRS),C/2007 Q3 (Siding Spring),C/2001 C1 (LINEAR),C/1910 A1 (Great January comet),C/2002 J4 (NEAT),C/1958 D1 (Burnham),C/2007 VO53 (Spacewatch),C/2005 G1 (LINEAR),C/1986 V1 (Sorrells),C/2009 W2 (Boattini),C/2006 S3 (LONEOS),C/2014 Q6 (PANSTARRS) )with the current positions of alpha centauri, proxima and barnard's star plotted as red dots.

 

[aramis]

The Oort cloud remains entirely hypothetical, there is no observational evidence to confirm or deny its existence.

Not quite...

http://www.astronomy.com/news/2014/...f-the-surfaces-of-objects-from-the-oort-cloud
http://www.astronomy.com/news/2014/03/major-new-dwarf-planet-discovered

There are more that have >5000 AU apogee...

 

[mike wightman]

Having read the articles I find that they make claims about objects, like comets, that could have originated in the oort cloud, if it exists. They do not provide any proof of the existence of the oort cloud as it was hypothesised.

The second article actually has the subtitle:

Scientists report the discovery of a distant dwarf planet, called 2012 VP113, which was found in the hypothesized inner Oort Cloud.

Until there is a lot more observational data the oort cloud remains a hypothesis.

 

[ShawnDriscoll]

I've done 3D using stacks of this. It works ok.

 

[sudnadja]

If you actually read the articles you will find that they make claims about objects, like comets, that could have originated in the oort could, but are a lot closer than the oort cloud as hypothesised.

I don't think they would have formed in the inner solar system and had an interaction which would have boosted their aphelions out that far, the comets are coming from (or going too) randomly around the sky rather than primarily in the ecliptic.

None of that rises to the level of "proof", which would probably require finding at least a few hundred objects in random mostly circular orbits between 10k and 50k AU, but there are icy bodies that are in orbit of the sun that have aphelions greater than or in some cases much greater than 5000 au.

Of the purposes of a traveller conversation, if the point is to find a deep space object in very far orbit of the sun for the purposes of refueling, I think there's enough evidence to suggest that it's fairly likely that there are comets that far out and remain realistic or plausible. I don't know if it's as plausible that TL9 or TL10 societies could find them, but I suppose we should find that out in short order.

 

[sudnadja]

I've done 3D using stacks of this. It works ok.

That's not bad, but it has the disadvantages of a 3d map, you can't lay it flat out on a table or look at it flat on a computer screen, without the advantage that real 3d can supply, that being precision positioning. If you're going to do a map like that, why not go all the way and just state that, for example, Barnard's Star is at {1.51308,0.908594,0.441631}?

How did you represent your map in actual play? Did you have it 3d printed or do you look at it (along with players) represented on a computer display?

 

[mike wightman]

No probs, I have no doubt that there is lots of stuff out there, and your use of such objects for your purposes makes a lot of sense.
The scientist in me doesn't like it when a hypothesis becomes a 'popular science myth'.

We will gather more data, and the oort cloud remains a very plausible hypothesis and as you say, there is enough stuff out there to provide fuel for TL9+ starships.

Great work by the way

 

[sudnadja]

No probs, I have no doubt that there is lots of stuff out there, and your use of such objects for your purposes makes a lot of sense.
The scientist in me doesn't like it when a hypothesis becomes a 'popular science myth'.

We will gather more data, and the oort cloud remains a very plausible hypothesis and as you say, there is enough stuff out there to provide fuel for TL9+ starships.

Great work by the way

Thanks!

And I agree, insofar as Traveller is a vehicle to teach at least somewhat more real science than we typically see in movies despite its flaws, it's best to avoid astronomic effects and objects that aren't at least highly likely, even if proof isn't immediately present.

In my own view of the the universe, I strongly suspect that a structure like the Hills Cloud and Oort Cloud exist and don't have a problem putting them into games as standard structures around stellar objects, but if it were somehow shown that the sun doesn't have an Oort cloud I'd have no problem taking it out of the game too. I suppose that a safe middle ground is to not have Oort clouds but do accept many long period comets.

Interstellar Wars suggests that there is a brown dwarf or rogue planet between Sol and Barnard's Star, and the current IR sky surveys should have excluded brown dwarfs at least, and I think "rogue planets" are of around the same hypothetical quality of Oort clouds - I don't see how they couldn't exist in that planets must occasionally get ejected from star systems and now they're floating gravitationally unbound through the milky way - but there's no proof of any of them yet.

I like the qualifications about hypothesized vs real in discussions like this, so thanks for that. I picked up a lot of "knowledge" as a kid from science fiction, and some of it stays with me today that may or may not be grounded in reality.

 

[aramis]

I don't think they would have formed in the inner solar system and had an interaction which would have boosted their aphelions out that far, the comets are coming from (or going too) randomly around the sky rather than primarily in the ecliptic.

None of that rises to the level of "proof", which would probably require finding at least a few hundred objects in random mostly circular orbits between 10k and 50k AU, but there are icy bodies that are in orbit of the sun that have aphelions greater than or in some cases much greater than 5000 au.

Of the purposes of a traveller conversation, if the point is to find a deep space object in very far orbit of the sun for the purposes of refueling, I think there's enough evidence to suggest that it's fairly likely that there are comets that far out and remain realistic or plausible. I don't know if it's as plausible that TL9 or TL10 societies could find them, but I suppose we should find that out in short order.

Given Oort's definition, if perigee is ≥5000 AU and the orbit isn't cleared, it's part of the Oort cloud.

There are multiple detected bodies matching that. Not as many as the Kuiper Belt, but it really only takes a handful to establish the pattern.

Actually, by the definition on phys.org, 2000 AU is sufficient.

The Oort Cloud is through to extend from between 2,000 and 5,000 AU (0.03 and 0.08 ly) to as far as 50,000 AU (0.79 ly) from the sun, though some estimates place the outer edge as far as 100,000 and 200,000 AU (1.58 and 3.16 ly). The Cloud is thought to be comprised of two regions – a spherical outer Oort Cloud of 20,000 – 50,000 AU (0.32 – 0.79 ly), and disc-shaped inner Oort (or Hills) Cloud of 2,000 – 20,000 AU (0.03 – 0.32 ly).

Read more at: https://phys.org/news/2015-08-oort-cloud.html#jCp[/quote