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Lieutenant
Posts: 1535
"Sicilian", or Extirpation
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The Standard Jump Points in a Star System are about as far from the star, as its Habitable Zone. Now, within all stellar Habitable Zones, the flux of star-light is about ~1400 W m -2 (as on Earth, at 1 AU from the Sun), since that flux will warm planets up enough to keep water from freezing, but w/o boiling either. And, the received flux of star-light, at a given distance, is equal to that star's Luminosity divided by (4 pi) that Distance squared. Thus, for all stellar Habitable Zones: L* / D2 = constantSo, DHZ ~ L*1/2But, the Luminosity of a star scales roughly as the fourth-power of its Mass (Bowers & Deeming. Astrophysics I: Stars, pg. ~28). So, a star twice as massive, shines some 16 times brighter (roughly). So, L* ~ M*4And so, DHZ ~ M*2Now, the Gravitational Potential Energy (U) at that distance is: UHZ = - G M* / DHZ ~ - 1 / M*Thus, since bigger stars are so much brighter, their Habitable Zones are much much farther away, where the pull of gravity is extremely weak. Conversely, since smaller stars are so much dimmer, their HZs are extremely close in, where gravity is comparatively stronger. So, consider some M-Class star, with a mass of 1/4th MSun. At its HZ, and at its Jump Points, the Gravitational Potential is about 4 times as negative. That is, the JPs are about 4 times deeper down, into the star's Gravity Well (as compared to those of the Sun). GAME FX for KF-DRIVES:KF-Drives work by warping space. Their performances are boosted, by ambient Space Curvature, which (crudely) scales with the Gravitational Potential. Thus, Jumping to, & from, the standard JPs, of low-mass stars, is easier, w/ KF-Drive technology, than Jumping to, or from, the S-JPs of high-mass stars. Therefore, although most Jumps are about 30 light-years long, Jumps from, and to, low-mass stars could conceivable exceed 30 light-years, while Jumps from, and to, high-mass stars could conceivably be restricted to less than 30 light-years. Assuming that KF-Drive efficiency is proportional to the product of the Space Curvatures (ie., the Gravitational Potentials ), of both the Departure & Destination stars, then the maximum Jump Distance will scale as: 30 light-years x UDept. x UDest. ~ 30 light-years x MDept.-1 x MDest.-1And, borrowing the basic figures from here, we have the following rough guidelines, for maximum Jump Distance (in light-years): Star-Type O B A F G K M
O 0.008 0.03 0.16 0.29 0.45 0.63 1.67
B 0.09 0.52 0.98 1.51 2.08 5.56
A 2.93 5.51 8.53 11.72 31.25
F 10.38 16.04 22.06 58.82
G 24.79 34.09 90.91
K 46.88 125.00
M 333.33
According to this analysis, Jumps are only feasible from, and to, A-Class stars, and below. |
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Major
Posts: 3493
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Certain stars are unlikely to have Habitable planets.
Eg, Blue Giants are very short lived, emit massive ammounts of radiation, and no planet, even in a liquid water radius of the star would survive long enough to develop a biosphere.
Dwarf stars, though very long lived, have such a small gravity field that rocky planets like earth are unlikely to form, they simply don't have enough matter in orbit.
In any case, the habitable zone has no bearing on the jump points (other than being affected by the square root rule)
Jumpships range isn't affected by the gravity fields involved. They simply can't jump in or our of a certain gravity strength. If your argument were valid, then you could jump almost infinitely far if you jumped into spaces lightyears away from stars. It would also change the way distance was measured strategically. Basically it would set up a pseudo space lane system, which in itself isn't unattractive (I love Sins of Solar Empire) but would invalidate the canon universe.
Not a bad system, but it's certainly not battletech. I'm not adverse to the introduction of new or different jump technologies, but like all things in battletech, they need to have some drawbacks. This doesn't really in terms of in-universe ease of operations. Clearly M class stars would become transport centers. They would be used to get close to other stars that weren't so easy to jump to.
Not very transferable to a Universe where the most successful House leader of the past century (Hanse Davion) fought a war run in waves rather than strikes at particular planets deep within the enemies territory. (which is even now stretched)
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Monsters in the Sky!
Moderator
Posts: 19068
Luft Konteradmiral, K.u.K. Luftflotte
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The Standard Jump Points in a Star System are about as far from the star, as its Habitable Zone. Umm ... wrong. The standard jump points for Sol are a lot further away than 1AU ... IIRC on the order of 10AU. So that's an incorrect assumption from the word go. Standard jump points are determined solely on the mass of the target sun - so standard jump points for a 2 solar mass red giant will be exactly as far from the centre of that star, as would the standard jump points for a 2 solar mass type A giant. KF-Drives work by warping space. Their performances are boosted, by ambient Space Curvature, Now, at this point you're making stuff up out of whole cloth. The 30LY limit is a fixed limit (subject to Interconnectedness' and WoB's research, neither of which work as per your hyppothesis). Now if you want to make stuff up, more power to your elbow. But please, you really fail to identify that your postulates and variations are not connected with the body of canon knowledge. For many of us, the statement According to this analysis, Jumps are only feasible from, and to, A-Class stars, and below really needs a qualifier like "provided you're prepared to abandon the canon description of K-F theory, and run with my alternative K-F-B (Kearny-Fuchida-Bismark) approach. I know I'd appreciate such qualifiers. W. |
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Writer
Posts: 16051
How's it sit? Pretty cunning, don't you think?
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really needs a qualifier like "provided you're prepared to abandon the canon description of K-F theory, and run with my alternative K-F-B (Kearny-Fuchida-Bismark) approach. I know I'd appreciate such qualifiers.
I second the motion. Just opening the post with, "This is a proposed home rule..." would save me an hour that I'd spend picking apart violations of canon in the post. The standard jump points for Sol are a lot further away than 1AU ... IIRC on the order of 10AU. Correct, about 10.2AU. Standard jump points and the associated proximity limits are illustrated in Strategic Operations on the map of the Sol system. DropShips & JumpShips, BattleSpace, AT2, AT2R, Explorer Corps, and Strategic Operations all provide detailed tables listing the distance of the proximity limit from the star, usually right beside the recharge time table. Bismarck: I noticed your rules do not address jumps to and from points in interstellar space. Your rules are entirely predicated on jumps from locations near stars. If low mass stars increase jump range, what happens when a JumpShip operates from space that is light-years from any star? |
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Major
Posts: 4216
Zakus FTW!!
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∞?
Personally I think the range is about fine, all one really needs it to be able to jump more than twice in a row.
Like being able to have like 3x LF batteries and then be able to charge them up all at the same time (with a 3x use of fuel).
After all ~1,500 - 3,000 xC is a fairly reasonable FTL speed. Not the fastest in SciFi but not all that slow either.
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Demi-Precentor Mu/Psi III
Moderator
Posts: 1869
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∞?
Personally I think the range is about fine, all one really needs it to be able to jump more than twice in a row.
Like being able to have like 3x LF batteries and then be able to charge them up all at the same time (with a 3x use of fuel).
After all ~1,500 - 3,000 xC is a fairly reasonable FTL speed. Not the fastest in SciFi but not all that slow either.
To be able to mount more than one LFB, I'd advocate making the LFB heavier... With a Compact Core, I could cram say 9 LFBs onto a Ship and have it be able to travel 300 lightyears in 5 hours or less while still being able to carry around 40% of it's mass as cargo. I'd personally like to see lighter K-F drives that can't jump as far. Also, a shorter-ranged Jump Drive that can charge faster, maybe? |
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Major
Posts: 4216
Zakus FTW!!
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To be able to mount more than one LFB, I'd advocate making the LFB heavier... With a Compact Core, I could cram say 9 LFBs onto a Ship and have it be able to travel 300 lightyears in 5 hours or less while still being able to carry around 40% of it's mass as cargo. I'd personally like to see lighter K-F drives that can't jump as far. Also, a shorter-ranged Jump Drive that can charge faster, maybe?
And cost a lot of funds (with "HMA rules" your looking at over 80 billion C-bills -I don't know what the new rules are like) and use some 3,555 tons of fuel per jump, -if you use all of the LF bats. |
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Lieutenant
Posts: 1535
"Sicilian", or Extirpation
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I thought that BT Jumpships required, and utilized, the Spacetime Curvature around stars (I thought Jumping was a Space-Folding technology). But, according to Wikipedia, Jumpships must actually avoid "the danger of Jumping while in a Gravitational Well" (Jumping is a "Hyperspace Transport" technology). That being the case, the 30 light-year limit represents the Deep Space, "zero-gravity", Theoretical Maximum. Surely, however, in practice, Jumping from stellar Gravity Well to stellar Gravity Well, that limit is never reached, as those stars' gravities actually impair Jumping. BT is fully consistent as is. The only caveat, of my aforesaid analysis, would be that Jumping to, and from, low-mass stars might actually be more restricted. Thus, while a Jump from gravity-free Deep Space to gravity-free Deep Space might reach 30 light-years, and Jumps from around O-Class stars might reach 29.5 light-years (say), Jumps from M-Class stars might max out at 28 light-years (say). ADDENDUM:Note that I only argued from Scaling Laws. Thus, even if the JPs around G-Class stars are at 10 AU -- to wit, 10 x DHZ -- as long as that ratio is the same for all stars, my aforesaid analysis is valid. Assuming that that is the case, being seemingly required by the need for Recharging combined w/ the increasing dimness of smaller stars, then the JPs around smaller, dimmer stars would still be comparatively deeper down into their Gravity Wells. And so, Jumps to, and from, such smaller, dimmer stars would be more impaired, and more limited in range, than those from bigger, brighter stars. |
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Writer
Posts: 16051
How's it sit? Pretty cunning, don't you think?
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I'm still not clear. Were you proposing home rules or were you seriously trying to interpret canon?
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Lieutenant
Posts: 1535
"Sicilian", or Extirpation
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According to Sarna-dot-net, "a JumpShip must operate in zone where gravity levels are below a certain minimum". The Proximity Distances listed for BO- and M9-Class stars suggest, that this limit is defined by: G M* / Dprox.2 < thresholdIf so, Dprox.2 ~ M*Now, the Stellar Flux received at the (innermost) JP is proportional to L* / Dprox.2. Thus, Stellar Flux ~ L* / M* ~ M*3Thus, there is much more starlight available, at the JPs around bigger, brighter stars. Such stars should afford faster Recharge Times, as, indeed, they do. |
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Writer
Posts: 16051
How's it sit? Pretty cunning, don't you think?
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I'm still not clear. Were you proposing home rules or were you seriously trying to interpret canon?
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Lieutenant
Posts: 1535
"Sicilian", or Extirpation
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Not clear about what ? I thought KF-Drives used Spacetime Curvature to "fold space". Were that they case, then, clearly, being deeper down in Gravity Wells would facilitate longer-range Jumps. In such a case, you could conceivably use Neutron Stars to Jump 1000+ light-years; or Black Holes to Jump even further (perhaps Galaxy to Galaxy??).
However, according to canon, KF-Drives are "gravity-limited". So, the 30 light-year limit is the "gravity-free" maximum; delving down deeper into stellar Gravity Wells surely actually impedes Jumps, limiting them to less than that 30 light-year limit.
GAME FX:
It is my understanding, that the Spacetime Curvature (K) caused by a Central Mass (M), at a given Distance (D), is (roughly) proportional to the Average Volume Density caused by that mass:
K ~ M / D3
But, the Proximity Distance (Dprox) scales as M1/2. Thus,
Kprox ~ M-1/2
Thus, the Spacetime Curvature, at the JPs, of bigger & brighter stars, is somewhat less than those around smaller & dimmer stars. But, the dependence is weak, and the effect not noticeably profound. Never-the-less, Jumps to, and from, smaller & dimmer stars are probably more limited than those from, or to, bigger & brighter stars (or, theoretically, from Deep Space).
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Monsters in the Sky!
Moderator
Posts: 19068
Luft Konteradmiral, K.u.K. Luftflotte
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Not clear about what ? I thought KF-Drives used Spacetime Curvature to "fold space". Your understanding is incorrect. Spacetime curvature inhibits formation of the KF field, preventing a jump initiating or terminating at that point. It has nothing to do with the 30LY limit of the jump. In canon, that is. As you keep describing things (in this and other posts) that don't connect with known canon facts (as far as anything in a purely fictional universe can be a 'fact', admittedly) it looks to us that you might be trying to describe alternate rules. If so, fine, but we'd appreciate your understanding that your suggestions are indeed alternate rules (aka 'house rules'). If you're suggesting that your posts describe the way the BT universe works, then they are unfortunately in many cases wrong, because they directly contradict canon fact. Cray and I tend to pick up on these - me because I'm an old fart with a moderately encyclopediac knowledge of trivia, and Cray because he's provided much of the theoretical framework which in the last 5-10 years has underpinned our understanding of the BT universe. Cray's work has involved trying to cope with a lot of arbitrary and occasionally contradictory material from 25 years of game development - eg. 'Mech fusion engines 'stackpoling' (they won't), or the 30LY KF limit (up until recently, an arbitrary one). One can't casually change these underpinnings without potentially changing the entire way the BT universe would have evolved, or rendering all the fiction and sourcebooks printed to date at variance. So, as we've indicated, if you wish to put forward your personal theories - fine. If you wish to put forward house rules - perfectly acceptable. In both cases it's helpful to others to mark your posts as such. If you wish to say however "this is the way the BT universe really works" - in the face of in-universe facts to the contrary - you're making a bolder assertion, and bold assertions require substantive proof - and substantive examination. W. |
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Writer
Posts: 16051
How's it sit? Pretty cunning, don't you think?
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Not clear about what ? Whether your are proposing house rules or trying to analyze canonical rules. Which are your posts here, Bismarck? House rules? |
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Lieutenant
Posts: 1535
"Sicilian", or Extirpation
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Your understanding is incorrect. Spacetime curvature inhibits formation of the KF field, preventing a jump initiating or terminating at that point. It has nothing to do with the 30LY limit of the jump. In canon, that is. I've acknowledged that at least three times, yes ? I quoted Wikipedia, Sarna.net, and said, of my original suggestions, " were that the case..." What is the confusion ? I thought KF-Drives worked one way (helped by Gravity), but, upon double checking, canon claims they work the other way (hindered by Gravity). I really don't understand what is so confusing. When I re-worked my original suggestion, for the canon KF-Drives, I found that " the effect is weak, and not noticeably profound" (paraphrase). The effect is opposite of what I thought at first, and essentially agrees w/ the canon Recharge Times from Dropships & Jumpships. What still needs clarification ? |
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Monsters in the Sky!
Moderator
Posts: 19068
Luft Konteradmiral, K.u.K. Luftflotte
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I assume you mean this post: I thought that BT Jumpships required, and utilized, the Spacetime Curvature around stars (I thought Jumping was a Space-Folding technology). But, according to Wikipedia, Jumpships must actually avoid "the danger of Jumping while in a Gravitational Well" (Jumping is a "Hyperspace Transport" technology). That being the case, the 30 light-year limit represents the Deep Space, "zero-gravity", Theoretical Maximum. Surely, however, in practice, Jumping from stellar Gravity Well to stellar Gravity Well, that limit is never reached, as those stars' gravities actually impair Jumping. BT is fully consistent as is. The only caveat, of my aforesaid analysis, would be that Jumping to, and from, low-mass stars might actually be more restricted. Thus, while a Jump from gravity-free Deep Space to gravity-free Deep Space might reach 30 light-years, and Jumps from around O-Class stars might reach 29.5 light-years (say), Jumps from M-Class stars might max out at 28 light-years (say). ADDENDUM:Note that I only argued from Scaling Laws. Thus, even if the JPs around G-Class stars are at 10 AU -- to wit, 10 x DHZ -- as long as that ratio is the same for all stars, my aforesaid analysis is valid. Assuming that that is the case, being seemingly required by the need for Recharging combined w/ the increasing dimness of smaller stars, then the JPs around smaller, dimmer stars would still be comparatively deeper down into their Gravity Wells. And so, Jumps to, and from, such smaller, dimmer stars would be more impaired, and more limited in range, than those from bigger, brighter stars. Specifically, this paragraph: BT is fully consistent as is. The only caveat, of my aforesaid analysis, would be that Jumping to, and from, low-mass stars might actually be more restricted. Thus, while a Jump from gravity-free Deep Space to gravity-free Deep Space might reach 30 light-years, and Jumps from around O-Class stars might reach 29.5 light-years (say), Jumps from M-Class stars might max out at 28 light-years (say). THey don't. Standard KF jumps to or from Wolf-Rayet, O, B, A, F, G, K, M, R, N and S sub-dwarfs - at whatever point in their evolution - have a maximum range of 30LY. They might have a maximum range of 10LY with orange jump-ships, but that's just as made up. Frankly, if all you're doing is asserting that things might be the case, what's the point? Particularly when the canon demonstrates that things aren't what you're proposing. Now you are doing one of two things here: 1) proposing that stellar mass might have an impact on jump range in some hypothetical re-arrangment of the BT universe. This is a "what-if", or a "house rule" if you prefer. 2) proposing that stellar mass might have an impact on jump range in the canon BT universe, where it demonstrably doesn't and there is no body of in-universe data to suggest this. Can you identify which of these you believe you are doing? Thanks. |
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Writer
Posts: 16051
How's it sit? Pretty cunning, don't you think?
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What still needs clarification ?
Whether you're proposing home rules or not. Please, tell us: home rules or your interpretations of canon. |
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Major
Posts: 6082
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If I may make an observation; It is possible that Bismark is making an analysis of what he thought was the canonical way CBT KF drives work based on the non-canonical information found on wiki and sarna.
Canon sources are published by Catalyst, Fanpro, FASA or Battlecorps. Other sources are not canon.
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Lieutenant
Posts: 915
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If I may make an observation; It is possible that Bismark is making an analysis of what he thought was the canonical way CBT KF drives work based on the non-canonical information found on wiki and sarna.
Canon sources are published by Catalyst, Fanpro, FASA or Battlecorps. Other sources are not canon.
Having contributed to the relevant articles on sarna.net I can assure you that they are meant to show the canonical facts, as derived directly from canonical material. No original theories or non-canon rulings in there. There are even contributions from Cray in there. The entries on Sarna.net are correct (as in canonically accurate), as far as I can tell. Bismark's quote is also correct. But his deductions from the quote are but one of many possible interpretations. |
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Major
Posts: 6082
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Let me rephrase: they might cite canon sources, but they are not directly canon. There are canonical descriptions of how K-F drives jump from almost 20 years ago and it is absolutely clear that stellar mass or gravity has nothing to do with jump distance; you can jump just as far from an itty-bitty star than from a massive supergiant. This statement, in the first post, goes directly against canon: According to this analysis, Jumps are only feasible from, and to, A-Class stars, and below. Thus, the analysis of the data is faulty because the data used is either incomplete or faulty. I cite AT2R (pp. 86-9) simply because it is the one book I have available to me and clearly indicates that jumps from all star classes are not just feasible but equal in terms of distance (30 LY). Nowhere in canon (until the Manassas drive) does it say that there is any variance in jump distance for any reason. Heck, even the earliest chronological references indicate that until the development of the HPG the size of the Terran Alliance was pretty much dictated by the 30 LY jump distance. BTW> Nothing personal, Bismark, just a bit of peer review. I'm using the premise that you are trying to analyze what you interpreted as canon (which is the way the post is presented), not that you are offering an alternative set of house rules for review. |
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Lieutenant
Posts: 1535
"Sicilian", or Extirpation
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Let me rephrase: they might cite canon sources, but they are not directly canon.
There are canonical descriptions of how K-F drives jump from almost 20 years ago and it is absolutely clear that stellar mass or gravity has nothing to do with jump distance; you can jump just as far from an itty-bitty star than from a massive supergiant.
This statement, in the first post, goes directly against canon: Don't you understand, that I retracted that comment ? After re-reading Sarna.net et al, I realized that Jumpships work best in Zero-G, not High-G. Thus, by being out past stars' Proximity Points, where Gravity is micro-low, all Jumps are ~30 ly, as per canon, as repeatedly stated, over and over and over again. The only minor caveat is, being technical, you could argue that Spacetime is comparatively more curved, at the Proximity Points, of low-mass M-Class stars. That being the case, then, since Spacetime curvature impedes Jumping... Jumps from M-Class stars might max out at, say, 29.7 ly, instead of the full, theoretical maximum, of 30.0. But that smidgeon of an effect does not, to this author, warrant all this hooplah. |
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Master Sergeant
Posts: 252
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... Spacetime is comparatively more curved, at the Proximity Points, of low-mass M-Class stars...
Could you please explain this in more detail? AFAIK, the proximity limit tables for any star type (notwithstanding the fact that the luminosity class should also be considered to infer the mass of a star) determine the distance at which the gravitational force acting on an object of ~2.5Mt is less than a certain (arbitrary) threshold, such that the star type considered has no effect on the local curvature of spacetime. |
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Lieutenant
Posts: 1535
"Sicilian", or Extirpation
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Could you please explain this in more detail? AFAIK, the proximity limit tables for any star type (notwithstanding the fact that the luminosity class should also be considered to infer the mass of a star) determine the distance at which the gravitational force acting on an object of ~2.5Mt is less than a certain (arbitrary) threshold, such that the star type considered has no effect on the local curvature of spacetime.
I looked around for some definitive answer. According to a post on Physics Forums, Spacetime Curvature ("K") is proportional to the Gravitational Potential ("U") around massive objects, U = - G M / R. Thus, in symbols, and speaking only of proportionalities, while ignoring all constants: K ~ M / RIf you run the numbers, from the PP Table in Dropships & Jumpships, I think you'll find, that High-Mass Stars have slightly greater K scores than Low-Mass Stars. Now, Spacetime Curvature impairs & impedes Hyperspace Jumps, "Spacetime curvature inhibits formation of the KF field, preventing a jump initiating or terminating at that point" (DPWT). So, I suggested, that the slightly greater Spacetime Curvature around some types of stars might mean that Jumps to/from those systems are slightly more limited in range -- say, 29.8 ly vs. 30.0 ly. DPWT seems to say, that it affects Jump Success Probabilities more than Range. Perhaps, thinking along the lines of BT, where weapon Ranges & Hit Probs are related, it affects both. Either way, I think the affect is surely very slight, and is not really worth further consideration. It only would have been worthwhile, if my original mis-understanding -- to wit, that (1) KF-Drives work better in more strongly curved Spacetime; and (2) that JPs are, therefore, as close as they can be to the central stars -- had been correct. In that incorrect case, since small stars are so much dimmer (L* ~ M*4), you can get so much closer to them, that your K-scores can get huge, and then you could jump ~300 light-years. But, that is completely backwards from canon. Way out at PPs, all K-scores will be very low; and, so they won't change th 30 ly canon rule Jump limit much at all. The only thing worthwhile, for the game, from my OP, is this discussion of Spacetime Kurvature, which could help generate ideas, or appear elsewhere. |
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