The Dyson Sphere (The Dyson Shell)

[Condottiere]

I don't think it's isolated, just that at this point, gravity is the only force that we know can have an effect there.

 

[Werner]

Thanks! I read it all the way you do... so I'm guessing one of the later versions of Traveller added that idea. I have the LBBs from 1977 and from 1981, and T5.

T5 DOES talk about "Straight Courselines" (pg 112 of BBB2): "Gravity Sources in Real Space affect Jumpline: a straight line course cannot pass through a bubble surrounding a mass of any appreciable size..." which to me completely contradicts page 118 BBB2, which says "A ship in Jump Space is totally isolated from Real Space," and "is undetectable." If the former is true, the latter cannot be... and in my mind (and in MTU) the latter is true, NOT the former.

They are trying to make it more like the Star Wars hyperdrive. In the novels, there was something called an interdicted which was used in the Thrawn Trilogy to yank Luke Skywalker's X-wing out of hyperspace as it passed by. Thrawn was good at making educated guesses and knew which region of space Luke's X-wing had to pass through and where to place the interdicted to yank him out of hyperspace.

 

[Condottiere]

They also had highways, which allowed the identification of chokepoints and approaches.

 

[Werner]

They also had highways, which allowed the identification of chokepoints and approaches.

Seems like Star Wars hyperspace is rather cramped. It was really confusing in the last Star Wars movie The Rise of Skywalker, apparently hyperspace was done up like a maze that a Starship had to travel through, there is no rhyme or reason for it existing except as a plot device.

 

[Condottiere]

I'm not sure if the Kessel Run qualifies, but it seems a retcon to explain why certain regions were isolated, and some prospered.

 

[aramis]

They are trying to make it more like the Star Wars hyperdrive. In the novels, there was something called an interdicted which was used in the Thrawn Trilogy to yank Luke Skywalker's X-wing out of hyperspace as it passed by. Thrawn was good at making educated guesses and knew which region of space Luke's X-wing had to pass through and where to place the interdicted to yank him out of hyperspace.

That goes back to an issue of JTAS (IIRC 22 - article "Jumpspace"

 

[mike wightman]

It doesn't say that in the Journal 24 article, there is nothing about jump lines or ships being precipitated against their will so to speak

In the article it specifically mentions (note that the exact quotes will come later) that the real universe gravity only affects a ship trying to enter or leave jumpspace, there is no mention of a ship in jump being precipitated out of jump space against its will.

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.

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 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.

At the end of the week in jump, the ship naturally precipitates out of jump space and into normal space. The exact time of emergence is usually predicted by the ship's computer and the bridge is well-manned for the event.

Note that the identical article appears in the new MgT JTAS so it is canonical for the MgT ATU...

So we have two sentences that make it clear that a ship must be actively engaged in leaving jumo space - i.e. the end of the week - for gravity to force the precipitation at 100D, and one sentence that mentions the rather ambiguous and contradictory final sentence...

 

[whartung]

So we have two sentences that make it clear that a ship must be actively engaged in leaving jumo space - i.e. the end of the week - for gravity to force the precipitation at 100D, and one sentence that mentions the rather ambiguous and contradictory final sentence...

An interesting quibble.

The quote you cited says "naturally precipitates out of jump space", which suggests that there is no activity done by the ship to leave jump, it just happens. The ship can't force it out, can't extend it, can't leave early. But natural forces of the phenomenon are what make you leave jumpspace, and it, naturally, will leave you at a minimum of the 100D mark.

But at the same time, while this is a natural phenomena, it's predictable. You know when you enter how long you'll be in jumpspace.

I haven't seen anything that says that if you misjump, you're in jumpspace longer, or shorter than normal, only that the real space distance traveled is unknown, at least at the start. Maybe once you enter, you can know not just when, but where you're coming out, even on a misjump.

"Cap'n, just as we jumped I accidentally spilled my smoothie in to the power feed and it looks like we're not ending up where we planned to."

As I've said before, I consider #24 the canonical reference to jump space. That doesn't explain the inconsistencies of everything after, which I write off simply to "best practices", but #24 I consider the singular reference and everything else viewed through that lens.

The biggest gap from #24 is not that it doesn't explain fuel use, it doesn't explain why massive fuel use is the most common way to use the jump drive.

 

[mike wightman]

My interpretation of that 'natural precipitation' is that precipitation from jump space does not require any action on the part of the crew or the jump drive, the jump is fixed at the start and you precipitate back into our universe after a week. If, during that precipitation, you are too close to a star or planet you will precipitate at the 100D limit.

That said the exit from jump space is determined by the machinery at the start, not some intervening body in our universe that happens to be 3 days along an imaginary jump line...

 

[Werner]

My interpretation of that 'natural precipitation' is that precipitation from jump space does not require any action on the part of the crew or the jump drive, the jump is fixed at the start and you precipitate back into our universe after a week. If, during that precipitation, you are too close to a star or planet you will precipitate at the 100D limit.

That said the exit from jump space is determined by the machinery at the start, not some intervening body in our universe that happens to be 3 days along an imaginary jump line...

That seems to argue that you can precipitate back into normal space inside a Dyson shell so long as you are more that 100 Dyson Shell thicknesses inside the Dyson Sphere, and also more that 100 star diameters from the star in the center of the Dyson Shell. So the ship appears inside the Dyson shell, and can't figure out were it is because it can get a navigational fix as all the stars are blocked by the surrounding shell. By shell thickness I include the thickness of any atmosphere on the inside of the shell. Since its 1g of centrifugal force let's say a standard atmosphere is 100 km thick, the shell itself is about 10 meters thick, so we'll ignore that. Thus the Starship can precipitate out about 10,000 km inside the shell. The inner limit is 100 times the cube root of the Star's mass in Earth masses expressed in Earth diameters (12,800 km) which is 88,720,650 km. So its greater than 88,720,650 km from the star but less than 149,990,000 km if the shell's radius is 150,000,000 km, and also greater than 150,010,000 km to account for the thickness of the shell and atmosphere.

 

[Condottiere]

Either gravity from Einsteinian space has an effect in jumpspace, or it doesn't.

If it doesn't, involuntary precipitation only takes effect on exit, which could be well within a hundred diameters.

 

[mike wightman]

No, the natural precipitation at the 100D boundary occurs as you are exiting jump space, but only if you would be naturally precipitating as a consequence of your jump plot.

Since one of the explanations of general relativity that the illusion we call the force of gravity is due to the time dilation effect of the mass/energy 'gradient' it could well be that as the ship is transitioning from jump space to normal space it is affected by this dilation effect to pop it out at the 100D limit and no closer.

 

[Condottiere]

The Uncertainty Principle seems to apply.

Because you can't observe what's happening at the exit, when you calculate jump coordinates.

Velocity, if such can be applied in jumpspace, stretches to the length of the jump.

And we're not sure where the starship is within the confines of jumpspace.

 

[mike wightman]

The Uncertainty Principle seems to apply.

No, the uncertainty principle is for quantum phenomena, general relativity is not quantum.

Because you can't observe what's happening at the exit, when you calculate jump coordinates.

You observe from a distance and then plot future positions - which is why jump is difficult to compute. Note that once you have made a jump and you are in the destination system you can make your jump much more accurate, hence the difference between jump cassettes and the generate program

Velocity, if such can be applied in jumpspace, stretches to the length of the jump.

No it doesn't. The distance of the jump is determined before you enter jump space.

And we're not sure where the starship is within the confines of jumpspace.

That's because we don't understand the jump space dimensions or their physics.

 

[Condottiere]

It's possible jump technology partially utilized quantum physics.

String theory could be the connection between entry and exit points.

If there's a canonical explanation, it will be fun to deconstruct it.

 

[Werner]

It's possible jump technology partially utilized quantum physics.

String theory could be the connection between entry and exit points.

If there's a canonical explanation, it will be fun to deconstruct it.

As far as I'm concerned, it might as well be magic.

 

[Kobeck]

CT. In JTAS.

I think a passing nod was given in the original LBBs... let me check

YES. Book 3 page 9 mentions both righworlds & "sphereworlds"

 

[Kobeck]

I had a thought... why not make the useable land area even bigger by making the gravity say 1.1g's at the equator. I am thinking 1.1gs would suck long term but I doubt it would kill a person outright

 

[Kobeck]

I think a passing nod was given in the original LBBs... let me check

YES. Book 3 page 9 mentions both ringworlds & "sphereworlds"

of course I meant RINGworlds