Is Hop Space the same as Jump Space?

[Grav_Moped]

all it would take to capture pirates or enemy fleets that jumped out of the system would be to move a large ship onto the space they jumped from within a week, and they would be forced to precipitate back there at the end of the jump.

Here's how to use that to send a message at jump-28 speed across a 1-xboat/day network.
(On a 1 per day J6 network, it'd be jump-42...


Which is why it was nerfed in T5.1.

 

[whartung]

The important thing to remember is: You are NOT traveling through the intervening space. You are in a different space entirely. Either a wormhole or a different universe or whatever.

GT has Jump Shadows and Jump Masking. Specifically, if Star X is directly between where you ship is in System A and your destination is in System B, then a week after entering jump space, you emerge 100D from Star X. So, while you may be in a different space, "normal" space is punching through at the gravity/tidal level to pull you out if you stumble 100D from something big enough.

 

[TheDS]

GT has Jump Shadows and Jump Masking. Specifically, if Star X is directly between where you ship is in System A and your destination is in System B, then a week after entering jump space, you emerge 100D from Star X. So, while you may be in a different space, "normal" space is punching through at the gravity/tidal level to pull you out if you stumble within 100D from something big enough.

(slight edit above for clarity)

But this intersection between spaces ONLY happens in the moments you're entering or leaving Jumpspace (according to pre-GT descriptions), not at any other time in the Jump. That's the Jump shadow affecting you. When you're IN Jumpspace, you have no connection to normal space at all. There is no jump-mask to keep you from going "through" things, because those things aren't in the universe you're now in.

Look at it this way: most people think of space two-dimensionally, like walking from Denver to Las Vegas, and gravity wells are the mountains between those places. Sure, walking is going to be hard, but you've got access to the 3rd dimension: your own airplane! You just fly over those mountains at an altitude of 30,000 feet like they aren't even there, BECAUSE THEY AREN'T THERE.

Except even that isn't enough. You're on a whole-nuther-plane of reality. There is no spoon... erm... mountain. You SEEM to fly through a star because you were on one side and now you're on the other, but you in fact went around it by folding space and creating a shortcut.

 

[whulorigan]

(slight edit above for clarity)

But this ONLY happens in the moments you're entering or leaving Jumpspace (according to pre-GT descriptions). That's the Jump shadow affecting you. When you're IN Jumpspace, you have no connection to normal space at all. There is no jump-mask to keep you from going "through" things, because those things aren't in the universe you're now in.

According to pre-GT, perhaps. (I do not recall if any of those ideas were actually discussed anywhere in JTAS or Challenge prior to GT).

But I would still argue that spacetime curvature (or some "transformed mathematical component" of mass-energy) still may have some sort of "projection" regarding jumpspace, as the effect of shadowing implies that the masking effect on jump may be a thing, and not simply be local to the initiation and termination points, but to the entire jump-course from the perspective of the initiation point at the moment of jump-initiation (even if there is only a "chance" of affecting the jump-solution). The difference between the airplane-flyover analogy you make and the jumpspace analogy is that gravity (or spacetime curvature) is just that - a topological curvature of dimensionality. It is entirely reasonable (or at least possible) that a "course" thru even an entirely extradimensional path may be warped (even if only slightly) by the mass-energy in some way just as it does the other 4 dimensions in which masses are imbedded. So it would be as if the canyons and mountains of your analogy still created small topological stretches and compressions above their geographic locations due to their "gravitational" presence in the model I am suggesting.

So if those masses are imbedded in our N-Space spacetime, our N-Space either could impinge on Jumpspace in some mathematical transformation (as in GT/T5), or mass-energy has an existence and extension that goes beyond our 4D Spacetime in some way, mathematically (possibly). But it need not, obviously, if that is not what you prefer.

The whole idea of jump-masking (not to be confused with jump shadow) completely destroys the game. If jump-masking was real, all it would take to capture pirates or enemy fleets that jumped out of the system would be to move a large ship onto the space they jumped from within a week, and they would be forced to precipitate back there at the end of the jump. Or put some big masses in the outer system between two stars and you can force ships to precipitate far away from any hope of rescue and rob them (if you're a pirate) or destroy them (if you're an SDB) at your leisure. Furthermore, it would become possible to communicate with a ship in jumpspace by use of gravity waves.

It doesn't under T5. The rules are explicit in that it is the spatial configuration of things IN ALL LOCATIONS at the instant of Jump Initiation that governs the Jump. So moving a ship or object somewhere after the Jump has commenced will do nothing. It also means that Jumping to uncharted locations is more dicey, as your lack of information concerning in-system and mid-transit objects creates potential (if rare) Jump issues, and even that information will initially be months or years out of date due to light-lag issues during initial astrogational observation. Scouts will want to initially keep Jump-rutters concerning uncharted locations.

 

[mike wightman]

Marc's article has several references to gravity affecting jump:

"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."

This is the 100D distance we have all come to know and love. Now things get interesting:

"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."

"When ships are directed to exit jump space", the ship must be being directed to exit jump space for the gravity well to have its effect, which is precipitation at the 100D threshold. This is repeated:

"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 result unpredictable. In some situations, the 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."

"For ships trying to leave jump space" so if a ship is not trying to leave jump space within 100D it is not automatically precipitated at 100D.

The GURPS authors got this wrong, and somehow convinced Marc. His article is explicitly clear - gravity only affects a ship when it is trying to enter jump space and when it is trying to leave. It is not in our universe while in jump and only when the ship is "directed to exit" or "for ships trying to leave jump space" does the 100D safety precipitation kick in.

Entry and exit are where gravity matters, the gravity at A and B, nothing inbetween matters in the slightest.

According to the article, which is reprinted in Mongoose Traveller JTAS 2, and still doesn't mention jump shadows or jump masking or intervening object shenanigans.

 

[whulorigan]

Marc's article has several references to gravity affecting jump:

"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."

This is the 100D distance we have all come to know and love. Now things get interesting:

"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."

"When ships are directed to exit jump space", the ship must be being directed to exit jump space for the gravity well to have its effect, which is precipitation at the 100D threshold. This is repeated:

"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 result unpredictable. In some situations, the 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."

"For ships trying to leave jump space" so if a ship is not trying to leave jump space within 100D it is not automatically precipitated at 100D.

The GURPS authors got this wrong, and somehow convinced Marc. His article is explicitly clear - gravity only affects a ship when it is trying to enter jump space and when it is trying to leave. It is not in our universe while in jump and only when the ship is "directed to exit" or "for ships trying to leave jump space" does the 100D safety precipitation kick in.

Entry and exit are where gravity matters, the gravity at A and B, nothing inbetween matters in the slightest.

According to the article, which is reprinted in Mongoose Traveller JTAS 2, and still doesn't mention jump shadows or jump masking or intervening object shenanigans.

Thanks for doing the search for the reference.

 

[mike wightman]

I didn't have to search... what took the time is the lousy formatting of the JTAS pdfs...

I should really save the above as a word document.

 

[Condottiere]

I suspect it's done for practicality.

You won't be able to kamikaze into a sun, because the game mechanics won't let you see out of the windscreen.

 

[whulorigan]

I suspect it's done for practicality.

You won't be able to kamikaze into a sun, because the game mechanics won't let you see out of the windscreen.

Well, that Psionic Mass Indicator isn't overly popular among Hyperspace pilots in Imperial Space . . .