Piracy by Walt Smith (a time capsule re-post from the 1999 TML)

[Condottiere]

Gravity well(s).

Which, apparently, do exert an influence into jumpspace.

So, if you're passing near enough one, your gravity based device would have something to bite on.

 

[whulorigan]

Gravity well(s).

Which, apparently, do exert an influence into jumpspace.

So, if you're passing near enough one, your gravity based device would have something to bite on.

Yes, but a gravity-well shadow in jump space is not a 1-to-1 spatial correspondence with real space, as the 1 week regardless of distance jumped, premature precipitation at less than full range after 1 week due to jumpline-blockage, and the random time-emergence factor demonstrate. An M-Drive or a G-Drive may not be able to meaningfully interact with the jump space "shadow" of a gravitational field (however that appears mathematically in jump space).

(You can of course hand wave it however you wish).

 

[whartung]

Apparently, you could change your realspace vector while in jumpspace.

That's a great point. That's a really good point. It's not a new idea at all, as I understand it, and it gives the ship an extra week(ish) of maneuver to fine tune their arrival vector at their destination.

Since the crew knows their exit time, they can take that into account as well. While jump arrival is +/-17 hours, as soon as you enter jumpspace, you know what that time will be and how long you will be in jump, and when you will arrive. Giving you all the information you need to maneuver as best you can to optimize rendezvous time once you exit.

 

[aramis]

That's a great point. That's a really good point. It's not a new idea at all, as I understand it, and it gives the ship an extra week(ish) of maneuver to fine tune their arrival vector at their destination.

Since the crew knows their exit time, they can take that into account as well. While jump arrival is +/-17 hours, as soon as you enter jumpspace, you know what that time will be and how long you will be in jump, and when you will arrive. Giving you all the information you need to maneuver as best you can to optimize rendezvous time once you exit.

Imperium's Sub-light interstellar travel makes reaction drives implausible, assuming one accepts it as canon (Marc does)...

 

[Straybow]

... While jump arrival is +/-17 hours, as soon as you enter jumpspace, you know what that time will be and how long you will be in jump...

I don't think I've ever seen such a description of the variability. No way could you know in advance, there is no communication between jump bubble and normal space, except the influence of the 100D gravity well. Gravity precipitation may take a few hours and a change in the jump drive behavior would give you that much notice.

 

[aramis]

I don't think I've ever seen such a description of the variability.

It is implied strongly with the rules in TNE, as a crit on navigation results in a "bingo jump" - one that drops one into a zero thrust to orbit exit point. That's an event which requires foreknowledge of jump duration in order to know where to place the exit point. That said, for those who consider each edition a separate canon, it's ignorable. Marc isn't exactly one of those people.

For example, Earth's orbital speed googles as about 30 km/s... There are several variable durations listed in canon... And let's use AC-Earth as our baseline... someone on reddit puts it at 24.8 km/s. S... speed is about 54.8 km/s, since A/B Cen are not on the eccliptic nor parallel motion... but hyp gives about 40 km/s or 144,000 km/hr

Time	Source	T Min	TMax	Dev
168 ± 10% hours	CT	151:12:00	184:48	±2,429,200 km
1d6: 1=6 days, 2-5=7 days, 6=8 days	MT Imp. Encyclopedia	144	192	±3,456,000 km
120 + (2d6 × 6) hours	MT: SSOM	132	192	±4,320,000 km
148 + 6d6 hours	MGT 1E CRB	154	184	±2,160,000 km

100 diameters is 1,274,600 km; hitting a bingo jump is unlikely without knowing the duration. Not impossoble, but definitely really hard. Especially given different ecliptics.

No way could you know in advance, there is no communication between jump bubble and normal space, except the influence of the 100D gravity well. Gravity precipitation may take a few hours and a change in the jump drive behavior would give you that much notice.

If the jump field slowly & steadily loses charge while in J-Space, then a few minutes in, the strength drop can most likely be determined to within a few minutes for exit time... but it there's a relativity error, experienced time aboard may be different

MTJ (which is canon, & GDW owned the rights, per the notice in the books) gives rules for group jump, so the variability is not inherently individual - tho' group jumps have normal variability for the group, and a very reduced variability to each other.

https://www.reddit.com/r/askscience/comments/30tvy8

 

[Condottiere]

Assuming, the time variability is based on some universal constants, such as distance, rather than randomization within a margin of error.

Also, that time experienced, dilated or compressed within the Zweiverse, in relation to the Einverse.

 

[mike wightman]

It boils down to the answer to this question - is jump duration meta-game information?

Do the 'in game' crew of a trader know from their jump cassette, generate program and or navigator the duration of the jump as it is enabled?
Or are the crew unaware as the duration of the jump is unknown to them, it is meta-game data.

Weighing canon sources the most likely answer is the first one.

 

[whartung]

No way could you know in advance,

JTAS 24 says that as soon as you enter jump, you know the duration of the jump. Obviously that precludes coming out early because you hit the 100D mark, but the crew knows how long the trip will be for a normal jump, but only after it starts.

The duration of a jump is fixed at the instant that jump begins, and depends on the specific jump space entered, the energy input into the system, and on other factors. In most cases, jump will last a week.

The exact time of emergence is usually predicted by the ship's computer and the bridge is well-manned for the event.

 

[Straybow]

I call BS. In order for jump duration to be known upon entry would require faster than light transmission of conditions on the far end of the jump path. Whoever wrote those JTAS and TNE rules didn't think that through. You might have an hour or so notice before end of jump as the jump field starts to interact with the precipitation or exit point.

 

[mike wightman]

Tosh and piffle, not to mention much straw catching.

I know where the moon will be in the sky in a week, a month, several years from now. Do I have causality breaking FTL foresight?

The conditions at the far end are known.

The destination system was mapped over a thousand years ago but telescopes and a computer simulation set up. This simulation is corrected every time new data arrives from the telescopes. When you have sufficient data to generate a jump cassette you send a jump ship to survey the system at close range and compare it with the model you have.

You jump back to your home system with an updated model that now allows for jumps to any generate equipped ships,

 

[kilemall]

Tosh and piffle, not to mention much straw catching.

I know where the moon will be in the sky in a week, a month, several years from now. Do I have causality breaking FTL foresight?

The conditions at the far end are known.

The destination system was mapped over a thousand years ago but telescopes and a computer simulation set up. This simulation is corrected every time new data arrives from the telescopes. When you have sufficient data to generate a jump cassette you send a jump ship to survey the system at close range and compare it with the model you have.

You jump back to your home system with an updated model that now allows for jumps to any generate equipped ships,

That’s assuming it’s only large stable gravitic bodies involved.

 

[mike wightman]

I'm assuming telescopes at least as good as the ones we have now - by TL9 they will be capable of so much more:

Space is called space for a reason.

Your first jump ship to a distant system will aim for the 100D limit of either the star or a gas giant. Every body that could pose a risk to your jump calculations will have been mapped for a long time.