Poster session for Empty Jump Hexes : possible solutions

[AKAramis]

Are people continually missing the fact that the 'masses required' part is only applicable to pre-Aslan Border Wars eras?

No. They (we?) are pointing out that it's not a logical follow-on to the nature of jump as described in the rest of the universe, and in fact is counter to the nature of the rest of canon.

How?

I see no contradiction at all. Imperium explicitly specifies mass to mass jumping (I note that Imperium was apparently re-released in 1990, did that change anything? I'm guessing the version with the CT CD is the 1977 version). Imperium is canon, it's listed as such by Marc himself.

The rest of canon doesn't conflict at all with this. So the Vilani and anyone else in the 1I needed to do mass to mass jumps to extend as far as they did - whoopteedoo. Does anything change? No. They just take the time and effort to find brown dwarfs or rogue planets where they need to cross and that's that. Problem solved.

And after that, it just doesn't matter. Everything from the Aslan Border Wars onwards can do DSJs. That's everything in T4, the Traveller Adventure/Book, CT, MT, TNE, T20, and anything else can still do empty hex jumps without masses after that era. Old canon is not contradicted at all.

"counter to the nature of the rest of canon" means nothing. What's important is whether it specifically renders something already in canon impossible, and it doesn't.

Mass centric jumps would require a band where jump/dejump is possible. the rest of canon (every other reference I've seen excet Imperium and GTIW) makes it clear that you want distance from masses to jump.

The fact that masses eject you from jump at 100 diameters, and it's stated as "violently" in some editions, implies that the mass-shadow has an inverse gravity in J-Space, at least on entry/exit.

Aiming for a gravity well is inviting violent exit.

AM 6 also mentions that "The zero-G environment of the asteroid belt was exactly what was required before the space rending effects of jump drive could be even seen."

Gravity was linked to being inimical to jump in AM 6 fluff, as well as CT rules. That gravity would then be requisite would be mentioned.

(Note: Albedo's Jump drive works by inverse gravity from gravity well to gravity well, using the first as the accelerator, and the second as the brakes... but it specifies also that deep space jump is thus impossible due to the lack of gravity, and that too deep in, and the result is explosive. But Albedo, similar as it is to TL9 Traveller, isn't Traveller.)

 

[captainjack23]

Lets stop arguing here, because it is only vaguely relevent to the thread topic; it's an important issue and deserves not to be folded into this thread. My 2 CrImp.

In case either of you two overlooked it...... :wink:

 

[Ishmael]

what about misjumps?

they can end ( badly ) in a hex without a mass in it can't they?
or is there a variant where ships 'misjump' into an empty hex, but cannot come out of jump and are thus stuck forever in limbo

I'd see ( with my limited knowledge ) that when Imperium states jumping from mass to mass, that it didn't specifically state the reason for that rule ( probably a game issue concerning choke points and not having to keep track of a long supply chain. ).

So instead of jumping in or out requiring mass... ships required a fuel source, aka a gas giant or something like that.

and the 100d rule; maybe its to prevent a ship appearing INSIDE another ship or planet ( although that might be cool in a wierd 'philadelphia experiment kind of way )...and that rule means you'd actually have to FLY your ship into space.

just my opinion.

 

[EDG]

Mass centric jumps would require a band where jump/dejump is possible. the rest of canon (every other reference I've seen excet Imperium and GTIW) makes it clear that you want distance from masses to jump.

The fact that masses eject you from jump at 100 diameters, and it's stated as "violently" in some editions, implies that the mass-shadow has an inverse gravity in J-Space, at least on entry/exit.

Aiming for a gravity well is inviting violent exit.

So what, you're arguing now that masses should not be required for jumps at all?

I'm pretty sure (can't confirm right now, I seem to have misplaced the copy of the article I downloaded from JTAS online) that Marc Miller himself actually said that masses were required for jumps in his "Jumpspace" article from JTAS #24.

AM 6 also mentions that "The zero-G environment of the asteroid belt was exactly what was required before the space rending effects of jump drive could be even seen."

It's not zero-G there though. It's very low G, but given asteroids floating around nearby and the effects of the sun's gravity well and other planets, you're still not at zero-g.


I don't even know what you're arguing for now though. I asked "how does going from a mass-to-mass paradigm to a mass-to-empty or empty-to-empty paradigm contradict canon", and you've just thrown a bunch of unrelated factoids at me in response.

In fact, you've just reinforced what I've been saying - it seems to me that mass-to-mass is easier because you just hit the 100D limit and get pulled out of jump. Sure it could be a a bit rougher but it's survivable. Then later on some bright spark figures out how to deliberately leave jump space without having a mass do it for you, and voila, you can jump into empty space now (or come out beyond the 100D limit in a system).

Again, there are no contradictions with existing canon.

 

[Ishmael]

I'd go so far as to say that mass inhibits jump

the deeper you are in a gravity well, the greater the chance of a misjump
a ship in jump cannot get deeper into a gravity well than 100d

entry and exit from jump is safer outside of a gravity well, which implies safer away from mass, aka, jumping in and out of j-space is easier without mass nearby
Does greater gravity make jumping easier ?... or harder

 

[EDG]

I'd go so far as to say that mass inhibits jump

the deeper you are in a gravity well, the greater the chance of a misjump
a ship in jump cannot get deeper into a gravity well than 100d

entry and exit from jump is safer outside of a gravity well, which implies safer away from mass, aka, jumping in and out of j-space is easier without mass nearby
Does greater gravity make jumping easier ?... or harder

No argument there. It is impossible to arrive within a 100D limit, but it is possible to leave from within it (with a greater chance of misjump the closer you are to the mass). That's all canonical.

But if you're trying to say that "mass makes things more difficult, therefore the ideal situation is to have no masses involved" then there's no evidence for that. You're in a gravity well no matter where you are in a planetary system (because of the primary star and planets around you), but while in interstellar space the ambient field is orders of magnitude lower, it's still not zero because you're still under the tiny effects of gravitational influences of the distant stars around you. But we know that jumping works exactly the same from 100D all the way out to infinity (since we're talking distance here), and doesn't somehow get even easier at 1000D or 10000D or 1,000,000,000D. So being further than 100D doesn't make it any easier to jump out, but being within it does make it harder to jump out.

 

[Ishmael]

But if you're trying to say that "mass makes things more difficult, therefore the ideal situation is to have no masses involved" then there's no evidence for that. You're in a gravity well no matter where you are in a planetary system (because of the primary star and planets around you), but while in interstellar space the ambient field is orders of magnitude lower, it's still not zero because you're still under the tiny effects of gravitational influences of the distant stars around you. But we know that jumping works exactly the same from 100D all the way out to infinity (since we're talking distance here), and doesn't somehow get even easier at 1000D or 10000D or 1,000,000,000D. So being further than 100D doesn't make it any easier to jump out, but being within it does make it harder to jump out.

There's no evidence against it either although I'd say that the reasons I already stated might be a hint in that direction. That and jump wasn't discovered until experiments were done away from significant mass. I know that there will never be zero mass. Just areas of very very tiny influences from mass ( as opposed to bigger influences ).

We don't know that jumping out is the same at 1,000d or 1,000,000d or infinity as jumping out at 100d...insufficient data, and the resolution is simply too coarse for it to be bothered with in game terms.... after a few decimal places, will a few more matter the way the rules are written? Maybe 1,000,000d is .0003% safer than 1000d...
It seems that there is a dearth of evidence for either side here.

of course, I'm now just talking to be talking.
I suspect the real reason for prior canon instances of 'no jumping into empty hexes' is simply for refueling reasons to avoid the hassle of keeping track of a supply chain ( lots of tankers ). The canon reasons come from Dark Nebula, GT:IW and Imperium? ( all mostly strategic games, yes?)... are there others? ( I came late and am no canonista for sure...just opinionated )

IMTU ( regardless of what OTU says ), jumping is easier away from mass

I may have to figure out what the acceleration due to gravity is at 100d from earth and say THAT'S the limit...then work it out for all planets in a system..and the sun. I wonder if its possible to build a huge heavy-armor ship that curves space enough to inhibit a safe jump. Spreadsheets...gotta luv'em

 

[captainjack23]

So, I was discussing this with some of my players at the game, and what hit me was this: my argument against the ideas that require the Vilanii were wooden headed either intellectually or culturally, (and didn't use the drive at it most effective ways) is entirely based on the real world, and real world cultural and sociological norms. .

Unfortunately for me, hard sf or not, traveller is based on golden age SF (sometimes golden age space opera).... and the cunning humans who outwit the hidebound aliens is a basic trope ! :idea: :idea: It has to be true ! :idea: :idea: What was I thinking ?

Oh, wait. Still leaves the Terrans acting stupidly . Darn. Toss that one out.
Back to you.


:mrgreen:

 

[EDG]

I may have to figure out what the acceleration due to gravity is at 100d from earth and say THAT'S the limit...then work it out for all planets in a system..and the sun. I wonder if its possible to build a huge heavy-armor ship that curves space enough to inhibit a safe jump. Spreadsheets...gotta luv'em

Ideally I'd toss the existing 100D limit into the garbage where it belongs and change it for something based on g-field strength. In fact, I did do that for my own SF setting.

But Traveller canon defines it by the diameter of the object, not its mass. Which gives you strange situations like a Neutron Star having a 100D limit of something like 2000 km, despite having twice the mass of Sol. Meanwhile, a "living" star with twice the mass of Sol has a 100D limit of about 2.5 AU.

Another oddity is that the 100D limit of a 5 AU radius supergiant like Antares is 1000 AU. But if you base the jump limit on gravity, then most of the time the limit is well within the star itself. So on the one hand you have to make a months (or years) long detour if you're caught in Antares' jump shadow, and on the other hand you can jump in right outside the star.

That said, I should point out that the "gravity based jump limit" thing is really something worthy of its own thread. It's something that crops up on discussion boards fairly regularly...

 

[captainjack23]

I may have to figure out what the acceleration due to gravity is at 100d from earth and say THAT'S the limit...then work it out for all planets in a system..and the sun. I wonder if its possible to build a huge heavy-armor ship that curves space enough to inhibit a safe jump. Spreadsheets...gotta luv'em

Ideally I'd toss the existing 100D limit into the garbage where it belongs and change it for something based on g-field strength. In fact, I did do that for my own SF setting.

But Traveller canon defines it by the diameter of the object, not its mass. Which gives you strange situations like a Neutron Star having a 100D limit of something like 2000 km, despite having twice the mass of Sol. Meanwhile, a "living" star with twice the mass of Sol has a 100D limit of about 2.5 AU.

Another oddity is that the 100D limit of a 5 AU radius supergiant like Antares is 1000 AU. But if you base the jump limit on gravity, then most of the time the limit is well within the star itself. So on the one hand you have to make a months (or years) long detour if you're caught in Antares' jump shadow, and on the other hand you can jump in right outside the star.

I suppose one has to assume that a universe which allows FTL, and in which time may be a constant may have odd relationships to normalspace physical relationships. I don't have the time or the math to prove it, but the lack of, or wonkyness of mass in jumpspace may just be what enables FTL. Possibly the closest analogue is "anti-dark" matter; in this case matter which has no gravitic (and thus mass based) interactions.

Theres some other ideas I have, but the last time I wrote them , they.....well, didn't make sense ......or possibly TLR.

 

[captainjack23]

That said, I should point out that the "gravity based jump limit" thing is really something worthy of its own thread. It's something that crops up on discussion boards fairly regularly...

As was pointing out the same regarding the "what is Canon"discussion....and look where that got me..

"One cannot hold back a wave....but surfing is always an option......"

 

[AKAramis]

That said, I should point out that the "gravity based jump limit" thing is really something worthy of its own thread. It's something that crops up on discussion boards fairly regularly...

As was pointing out the same regarding the "what is Canon"discussion....and look where that got me..

"One cannot hold back a wave....but surfing is always an option......"

The Gravity Based Jump Limit is a GOOD idea.... but it isn't canon. Why is a darned good question... I believe the answer to be quite simple ease of play pre-calculator.

EDG:
Ishmael pretty well pointed out the point I was trying to make. Simplified further:
Gravity is a hazard to jump entry/exit.
Less gravity is less risk.
Therefore requiring a gravity well for entry/exit is requiring a higher risk than would be an empty hex, and that does not make much sense.

I also pointed out that the gravity required model is used in another great setting... it was a stream of consciousness flow. Sorry if it confusd

Also, I treat all the pre-HG2 stuff as questionable for the OTU, simply because most of it has a small-ship universe in mind with a darker, more Star Wars like, Imperium, and the idea a unified canon seems to arise around 1981... with HG2 and 2nd Ed Classic Traveller.

 

[EDG]

Gravity is a hazard to jump entry/exit.
Less gravity is less risk.
Therefore requiring a gravity well for entry/exit is requiring a higher risk than would be an empty hex, and that does not make much sense.

Well, I've asked someone to track down the relevant bits from Marc Miller's Jumpspace article in JTAS #24, so let's see what he said (emphasis mine):

"Entering jump is possible anywhere, but the perturbing effects of gravity make it impractical to begin a jump within a gravity field of more than certain specific limits based on size, density, and distance. The general rule of thumb is a distance of at least 100 diameters out from a world or star (including a safety margin), and ships generally move away from worlds and stars before beginning a jump. The perturbing effects of gravity preclude a ship from exiting jump space within the same distance. When ships are directed to exit jump space within a gravity field, they are precipitated out of jump space at the edge of the field instead...

"Gravity has extraordinary effects on the function of the jump drive. Jump drive transitions to the alternate universes of jump space are severely scrambled within the stresses of a gravity well; the transition cannot usually take place within the stresses of a gravity well. When it does, the turbulence created by the gravity well makes the results unpredictable. In some situations, the ship is destroyed; in others, it merely misjumps.
"On the other hand, there seems to be a built-in safety feature for ships trying to leave jump space within 100 diameters of a world. Ships naturally precipitate out of jump as they near the 100 diameter limit."

So what can we get from that?

1) Jump is possible to initiate anywhere - from within a gravity well or from deep in interstellar space.
2) Ships are forced out of jump at 100D from a body.
3) Ships jumping out from within 100D is possible but the ship has a greater chance of misjump.

All from the pen of Marc Miller himself.

I've asked for clarification about whether there's anything said regarding being able to come out of jump without a mass there. But from the parts quoted at me here, it seems that actually you need a mass to pull you out of Jump. However, if that is true then it's not unreasonable to suppose that the ability to exit jump beyond the 100D limit (or with no mass there at all) could have been developed later via better technology or different calculation techniques or whatever. The question is, did Marc specifically say that this was impossible to do or not in the article - if not, it can be added later by someone else, and if so then it can't be.

The only significance of the "asteroid belt tests" is that you're beyond the 100D limit when you jump. It's not that it's "zero-g", it's just that you have are beyond 100D which gives you the minimum chance of failure which presumably is more important for prototypes. The tests would have worked at the L4 point of Mars' orbit, or 180 degrees from the planet around Neptune's orbit for all it makes any difference, just so long as it's beyond 100D. Once the tech is developed a bit more then presumably you can try jumping out from within 100D of an object but will have a greater chance of failure.

Note that despite going on about how gravity is all important, he still says "within a gravity field of more than certain specific limits based on size, density, and distance" which is presumably his excuse for the 100D (radius-based) limit.

Also, I treat all the pre-HG2 stuff as questionable for the OTU, simply because most of it has a small-ship universe in mind with a darker, more Star Wars like, Imperium, and the idea a unified canon seems to arise around 1981... with HG2 and 2nd Ed Classic Traveller.

Well that's great, but last time I looked HG was canon. So whether you like it or not, Traveller is not a small-ship universe.

 

[Ishmael]

.... But from the parts quoted at me here, it seems that actually you need a mass to pull you out of Jump. However, if that is true then it's not unreasonable to suppose that the ability to exit jump beyond the 100D limit (or with no mass there at all) could have been developed later via better technology or different calculation techniques or whatever. ...

I'm afraid that I don't follow your reasoning as to why the quotes shown indicate a need of a mass to pull you out of jump. I saw nothing that forces that conclusion.
On the other hand, mis-jumping ships have a good chance of coming out of jump in an empty hex, which proves that mass is not needed.

Note that despite going on about how gravity is all important, he still says "within a gravity field of more than certain specific limits based on size, density, and distance" which is presumably his excuse for the 100D (radius-based) limit.

I'm not sure of your intended meaning here.
The gravity field strength is determined by size,density and distance, of course. I'm sure thats what he meant. Yet I doubt people like to stop play to fool with a calculator over something like that, so a rule of thumb of 100d was pulled out of thin air to use with ordinary worlds ( rock, ~5.5g/mm^3, etc. ). At least, that's how I see it so far.

to recap;
Enter jump-space anywhere ( although a gravity field increases the risk of misjump as field strength goes up )
Exit jump-space anywhere ( as implied by mis-jump rules ) although a gravity field above a certain strength precipitates a ship back into normal space.

to add fuel to the fire.....
MT postulates a tech 16 'jump damper' which projects a 'pseudogravity well ' near a ship to prevent it from jumping out of combat.
This assumes that its possible to have gravity wells in the absence of mass. Clearly mass, in and of itself, means nothing to this whole debate... its the gravity_well/space_curvature that matters.

hmmmmm...
If gravity is propagated by waves, then perhaps a there exist areas where wave interferences cause standing waves representing strong gravity fields ( which affect jump drives ) or areas where the waves cancel each other out for no gravity or even perhaps areas of negative gravity( standing trough?). This probably isn't not possible, but hey...its sci-fi...space storms and the like, right?

come to think of it...how does negative gravity affect entry/exit and jump-space?
-------------------------

as always, its just my opinion concerning a game

 

[AKAramis]

So what can we get from that?

1) Jump is possible to initiate anywhere - from within a gravity well or from deep in interstellar space.
2) Ships are forced out of jump at 100D from a body.
3) Ships jumping out from within 100D is possible but the ship has a greater chance of misjump.

All from the pen of Marc Miller himself.

Most people interpret the exit bit not to be "you have to aim inside" but "If you aim inside, you come out at 100D."

Also, I treat all the pre-HG2 stuff as questionable for the OTU, simply because most of it has a small-ship universe in mind with a darker, more Star Wars like, Imperium, and the idea a unified canon seems to arise around 1981... with HG2 and 2nd Ed Classic Traveller.

Well that's great, but last time I looked HG was canon. So whether you like it or not, Traveller is not a small-ship universe.

Actually, Traveller is canon for both Small Ship and Large ship universes... but they are not both the OTU.

I'll grant that the OTU is clearly a Large Ship universe. But:

OTU is a subset of Canonical Traveller
Small Ship Universe is a subset of Canonical Traveller.
OTU and SSU are not a union, but do intersect.

Marc has never taken the effort to separate OTU from Rules Canon.

 

[EDG]

I'm afraid that I don't follow your reasoning as to why the quotes shown indicate a need of a mass to pull you out of jump. I saw nothing that forces that conclusion.

Which is why I said I'm waiting for further clarification on that

But it seems that ships trying to exit within 100D of a mass WILL be forced out of jump at 100D. The question is whether that article says that a ship as HAS to come out of jump this way, or if it says nothing about it, or if it says that they can come out in empty space without being forced out of jump.

On the other hand, mis-jumping ships have a good chance of coming out of jump in an empty hex, which proves that mass is not needed.

Well no, it doesn't. It proves that if you have a misjump, weird things can happen that may not normally happen.

I'm not sure of your intended meaning here.

I mean it's a technobabble fudge for "I've arbitrarily decided that the jump limit is actually based on radius, not gravity, despite going on about how gravity is the limiting factor everywhere else".

Yet I doubt people like to stop play to fool with a calculator over something like that, so a rule of thumb of 100d was pulled out of thin air to use with ordinary worlds ( rock, ~5.5g/mm^3, etc. ). At least, that's how I see it so far.

One more table showing g-based jump limits in the book wouldn't have crippled anyone's games...

MT postulates a tech 16 'jump damper' which projects a 'pseudogravity well ' near a ship to prevent it from jumping out of combat.
This assumes that its possible to have gravity wells in the absence of mass. Clearly mass, in and of itself, means nothing to this whole debate... its the gravity_well/space_curvature that matters.

Yes, well, when you start bringing artificial gravity then things go right out of the window. Technically ships with a 1g artificial gravity should have the same effect on nearby objects as a planet with 1g. And yet somehow the field is constrained to be within the ship only.

My interpretation of this is that artificial gravity isn't really gravity at all - it's actually pseudo-gravity. You see this all the time in spinning objects - when you spin a bucket of water the water stays in the bucket because of centripetal forces - but it's not like anything outside the bucket is pulled toward it as well. The same sort of thing must be going on here.

The "jump damper" may just be a way to project the artificial gravity pseudo-force to a remote target.

If gravity is propagated by waves, then perhaps a there exist areas where wave interferences cause standing waves representing strong gravity fields ( which affect jump drives ) or areas where the waves cancel each other out for no gravity or even perhaps areas of negative gravity( standing trough?). This probably isn't not possible, but hey...its sci-fi...space storms and the like, right?

The way I see it is as the classic 'rubber mat' of spacetime - put a mass on it and it makes a dent. Around the dent, spacetime isn't flat - it has a slope. Jump needs to be initiated in flattish spacetime to work - the steeper the slope, the greater the chance of misjump. And you can't arrive in realspace above a slope of a certain steepness.

That'd work great if you had a g-based limit, but goes out of the window for a radius-based limit.

come to think of it...how does negative gravity affect entry/exit and jump-space?

Don't think it's ever been mentioned... I'm not even sure you can get a region of space (even artificially) in the OTU where antigravity would repel everything.

as always, its just my opinion concerning a game

Look, we all know it's a game. That doesn't mean we can't take what it says seriously for the purposes of discussion though, does it.

 

[EDG]

Most people interpret the exit bit not to be "you have to aim inside" but "If you aim inside, you come out at 100D."

Ah, but is it an interpretation, or is that explicitly said? If it's just an interpretation, then there's room for licensees to clarify that.

Actually, Traveller is canon for both Small Ship and Large ship universes... but they are not both the OTU.

I'll grant that the OTU is clearly a Large Ship universe.

That's all that matters. That you prefer a "small ship universe" interpretation is just your own personal preference, based on the rules you pick and choose to use. But it still ain't canon.

 

[AKAramis]

Most people interpret the exit bit not to be "you have to aim inside" but "If you aim inside, you come out at 100D."

Ah, but is it an interpretation, or is that explicitly said? If it's just an interpretation, then there's room for licensees to clarify that.

A jump drive is both fast and simple. With one, it is possibe to move from here to there (where both places are at least one hundred planetary diameters out from any large masses) in a period of about a week.

CT, The Traveller Book, Traveller's Guide to the Universe, page 147. Emphasis mine.

Actually, Traveller is canon for both Small Ship and Large ship universes... but they are not both the OTU.

I'll grant that the OTU is clearly a Large Ship universe.

That's all that matters. That you prefer a "small ship universe" interpretation is just your own personal preference, based on the rules you pick and choose to use. But it still ain't canon.

Do you EVER stop trying to put words in other people's mouths that were not said?

I said both are part of the Traveller canon, but that the OTU is a subset of that canon. I didn't say I preferred one to the other. (in fact, at other times, I've said I prefer a mid-ship TU... to about 20KTd, as opposed to the 500KTd-750KTd Battleships of the OTU.)

The problem here is also conflation of rules and setting. Traveller is NOT JUST THE OTU. The OTU is a subset of Traveller.

Marc's canon list includes products with 1250 ton battlecruisers, 400 ton cruisers (CT core rules, CT Adv 1 & 4, Mayday.), and other such non-OTU items. Note that in later fan-handling, most of thse ships exist, but are redesignated. The Patrol Cruiser becomes a Patrol Cutter, for example, and the Merchant Cruiser of 1800 Td is just a exploratory merchantman.


So, by your apparent All Canon is Equal approach, in 1101, District 268 uses 1250Td cruisers, of a class which was in service in the SRW as frontline cruisers, while 100 years later, cruisers are more than 10 times as big...

talk about snapping the disbelief suspenders....

 

[EDG]

Do you EVER stop trying to put words in other people's mouths that were not said?

I'm not putting words in your mouth. You said that you treated all the pre-HG2 stuff as questionable for the OTU, but the reality is that it IS the OTU because it's canon.

I said both are part of the Traveller canon, but that the OTU is a subset of that canon. I didn't say I preferred one to the other. (in fact, at other times, I've said I prefer a mid-ship TU... to about 20KTd, as opposed to the 500KTd-750KTd Battleships of the OTU.)

IIRC you're one of the major proponents of "proto-traveller", aren't you? Which is all about how it should be a small ship universe using books 1-3?

The problem here is also conflation of rules and setting. Traveller is NOT JUST THE OTU. The OTU is a subset of Traveller.

It seems to me that you're just picking and choosing what you think is canon based on personal opinion rather than what is actually said. And in practical terms, Traveller is the OTU for precisely that reason - the rules and settings are too mangled up together to separate out.

 

[Ishmael]

On the other hand, mis-jumping ships have a good chance of coming out of jump in an empty hex, which proves that mass is not needed.

Well no, it doesn't. It proves that if you have a misjump, weird things can happen that may not normally happen.

I'm afraid it does. It proves that a ship in jump-space can make the transition back to normal space without any mass being present. Even if mass terminated jumps were normal, there does exist a condition where mass is not required. If one goes by the idea that initially mass was needed to terminate jumps, then this might be a way to explain "they solved that later" and explain a difference between j-1 at TL9 and j-1 at TL-10....but it's been solved by j-2 TL-11.

I mean it's a technobabble fudge for "I've arbitrarily decided that the jump limit is actually based on radius, not gravity, despite going on about how gravity is the limiting factor everywhere else".
.......
One more table showing g-based jump limits in the book wouldn't have crippled anyone's games...

It is technobabble fudge for " okay..figuring out gravity/tidal effects are a pain for people without calculators ( back in '77, calculators weren't as cheap or plentiful as they are now.), so just say 100d, which is far out enough and includes a safety margin too. Plus I don't have to write up lists for densities of different worlds/gas_giants/stars...which might show how wonky the atmosphere table is..."

I'm guessing its an 'ease-of-play' issue.

The way I see it is as the classic 'rubber mat' of spacetime - put a mass on it and it makes a dent. Around the dent, spacetime isn't flat - it has a slope. Jump needs to be initiated in flattish spacetime to work - the steeper the slope, the greater the chance of misjump. And you can't arrive in realspace above a slope of a certain steepness.

That'd work great if you had a g-based limit, but goes out of the window for a radius-based limit.

We agree on how things work at least.
I've already mention how I think it IS a g-based limit and that the radius part is for ease of play, so I'll drop that from this point forward.

I suppose negative gravity would be a bump where the rubber sheet is pushed upwards instead of downwards. Absolute value of the slope might be the limiter, so neg-grav makes for misjumps the same as regular grav.

But at the top of the bump, there would be a point where the slope was zero...no gravity at all...wouldn't Impie scientists want to find something like THAT! ( if it exists )
Hmmm zero slope in the exact center of worlds too ( bottom of grav-wells )...kind of hard to experiment there though.

Look, we all know it's a game. That doesn't mean we can't take what it says seriously for the purposes of discussion though, does it.

just reinforcing to all readers that I have no intention of going crazy here
Discussions about canon often devolve into jihads and inquisitions, I've found...its the reason I don't post so very often as I use to; I'm too old to foam at the mouth anymore.
:lol: