168 Hours plus or minus 10 percent

[atpollard]

Have you ever had one of those moments when everything suddenly makes sense. I was re-reading the article on Jumpspace by Mark Miller in the JTAS No. 24 and thinking about all of the debate on the inaccuracy of Jumps given the Time uncertainty inherent in a Jump (if you don’t know WHEN you will emerge from a jump then you don’t know WHERE the target world will be when you emerge). Four sentences from the article caught my attention:

“Jump takes 168 hours (+/- 10%) to complete. This time is related to the nature of the alternate space being traveled in, and to the energy applied. Where time is a variable in travel in normal space, energy consumption is a variable in alternate space; time is a constant.”

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

What if the time required for any particular Jump is a constant that is calculated just prior to the jump. The exact value for the constant “TIME” varies from 151.2 hours to 184.8 hours for all possible jumps (excluding misjumps), but the time for any particular jump is known with great precision. I find nothing in CT or the article to suggest that this is not exactly what Mr. Miller had in mind when he wrote the article.

With this understanding, virtually all of the controversy evaporates and peace is restored to the Imperium. Is there anything in any other published source which specifically contradicts this interpretation?

Arthur

 

[Whipsnade]

Originally posted by atpollard:
What if the time required for any particular Jump is a constant that is calculated just prior to the jump.

AT,

It isn't. The crew has an estimate of a jump's duration after jump is intiatied.

Is there anything in any other published source which specifically contradicts this interpretation?

Various descriptions and checklists scattered across CT and MT for starters. All them state plainly that estimated jump duration is only known after you enter jump.

It can also be inferred by the 'color text' we have regarding the OTU. X-boats don't squirt an ETA message just before the jump for instance.


Have fun,
Bill

 

[aramis]

Bill:

squirting it just prior to jump would make no difference.

After all, the source system has no way to communicate the information to the destination system... and no way to verify it before a second jump anyway.

On the other hand, MTJ has, in the MTQ&A (official answers) a process which allows a group to jump on one nav plot. They arrive within an hour or two of each other, rather than the 30 hour window of a normal jump.

This implies (but doesn't state) that the plot itself is greatly responsible for time taken to jump.

 

[Whipsnade]

Originally posted by Aramis:
squirting it just prior to jump would make no difference.

Aramis,

You misunderstood what I was saying.

If a ship knows the duration of it's jump before it jumps, it can then squirt out an ETA on the basis of that information.

If a ship knows the duration of it's jump before it jumps, it can then adjust it's exit point on the basis of that information.

Both actions rely on the same information; knowing the duration of a jump before you jump.

AT was suggesting that the latter may occur. I pointed out that, because the former doesn't happen, the latter cannot happen either. This is because both actions depend on the same prerequisite knowledge.

On the other hand, MTJ has, in the MTQ&A (official answers) a process which allows a group to jump on one nav plot. They arrive within an hour or two of each other, rather than the 30 hour window of a normal jump.

And the same passage says nothing about knowing the jump duration before you jump. All it talks about is how squadrons can 'synch' their jump plots.

This implies (but doesn't state) that the plot itself is greatly responsible for time taken to jump.

It implies nothing of the sort. All it implies is that vessels can share jump plot information in order to 'synch' their arrivals with regards to one another. They arrive close in time with regards to each other within the same 'band' of temporal uncertainty. The group's combined arrival time exhibits the same temporal uncertainty and the individual members of the group merely deviate from the group arrival time by a certain amount.

Also, any implications, if they do exist, are not enough. No version of Traveller links jump duration to the navigation roll. No versions, as in none.

T5 may do so, but it hasn't been released yet.


Have fun,
Bill

P.S. I've been holding off responding in the T5 forum thread regarding jump masking. I wanted to check with my friend who teaches semantics and get her opinion again. Guess who I had lunch with today?

 

[TheEngineer]

Hi !

I just can agree with Bill.
In any ruleset I know jump duration is a dice throw result...

MT ruleset also clearly specifies, that the jump duration is not modifiable by any navgation roll.

Jump space is a b....!

Regards,

TE

 

[atpollard]

Sorry to bother you Bill, but could you point out some of those "Various descriptions and checklists scattered across CT [and MT] for starters. All of them state plainly that estimated jump duration is only known after you enter jump."

I have been searching the CT CD but I have been unable to locate anything that doen't just say a Jump takes "about a week" - I can not even find a reference to 168 hours except the JTAS No. 24 article. (Of course with "3,000 pages and more than half a million words", I have not read everything).

 

[atpollard]

Originally posted by Bill Cameron:
If a ship knows the duration of it's jump before it jumps, it can then squirt out an ETA on the basis of that information.

If a ship knows the duration of it's jump before it jumps, it can then adjust it's exit point on the basis of that information.

Both actions rely on the same information; knowing the duration of a jump before you jump.

AT was suggesting that the latter may occur. I pointed out that, because the former doesn't happen, the latter cannot happen either. This is because both actions depend on the same prerequisite knowledge.

If the Travel time can also be calculated to "less than one part per ten billion" (a ten thousandth of a second) why bother "squirt out an ETA"? Anyone with a starship computer and a jump tape could calculate the ETA for themselves.

 

[TheEngineer]

Hi Arthur !

A reference example:
MT Encyclopedia, page 92, shows a checklist for space travel procedures.

8 Engage Jump Drive
...
9 Jumpspace
The vessel enters jumpspace and
travels to the world which the navigator
designated This ship remains in jump
space for about one week (under normal
circumstances)
Determine how much time the ship
spent in jumpspace by rolling 1D-
1 =6 days, 2 to 5=days, 6=8 days

And doesn't this "less than one part per ten billion" refer to the arrival point location ?
Guess it tells something about a perhaps 3 km variantion compared to the 31 billion km of the jump distance ?

Regards,

TE

 

[aramis]

Originally posted by Bill Cameron:
</font><blockquote>quote:</font><hr />Originally posted by Aramis:
[qb]squirting it just prior to jump would make no difference.

Aramis,

You misunderstood what I was saying.

If a ship knows the duration of it's jump before it jumps, it can then squirt out an ETA on the basis of that information.

If a ship knows the duration of it's jump before it jumps, it can then adjust it's exit point on the basis of that information.

Both actions rely on the same information; knowing the duration of a jump before you jump.

AT was suggesting that the latter may occur. I pointed out that, because the former doesn't happen, the latter cannot happen either. This is because both actions depend on the same prerequisite knowledge.
</font>[/QUOTE]And neither of which says it doesn't exist.

</font><blockquote>quote:</font><hr />On the other hand, MTJ has, in the MTQ&A (official answers) a process which allows a group to jump on one nav plot. They arrive within an hour or two of each other, rather than the 30 hour window of a normal jump.

And the same passage says nothing about knowing the jump duration before you jump. All it talks about is how squadrons can 'synch' their jump plots.

This implies (but doesn't state) that the plot itself is greatly responsible for time taken to jump.

It implies nothing of the sort. All it implies is that vessels can share jump plot information in order to 'synch' their arrivals with regards to one another. They arrive close in time with regards to each other within the same 'band' of temporal uncertainty. The group's combined arrival time exhibits the same temporal uncertainty and the individual members of the group merely deviate from the group arrival time by a certain amount.
</font>[/QUOTE]No, it does imply it if one isn't so hidebound determined to say traveller is broken that one can't accept implications logically.

Because, if two shipps don't sync plots, each rolls separately. If they do, they arrive in a far smaller time window relative to each other.

A rolls Variability from b = up to 33.6 hours
A&B share the same plot, then variability is (IIRC) only 11 hours.

So, the jump plot itself accounts for some 22 hours.

Note, I said (both times) the jump plot, not the skill roll.

the implication is there in the math presented in MT, SSOM, and MTJ.

 

[aramis]

Arthur: MTIE, in the encyclopedia section, lists the 168 &plusmmn;10% hour figure. On page 92, it lists a shorthand that TE quotes.

SSOM provides a randomized multi-dice roll. I can't check it at the moment, but ISTR 6d6+145 hours.

The checklists Bill mis-cites are in MT Referee's Companion. They show none of what he claims, other than for certain elements of shipping, jump exit points are not at 100 diameters.

 

[Hal]

I gotta wonder if those PDF disks will prove more of a bane than a boon in the long run <g> Ok, I'm kidding there. I wish that searchable PDF's had been around back in the day so that authors could have looked back and read some of what they were writing versus what had been written - to avoid canon conflicts as it were <g>.

I was surprised to see that the 168 hours +/- 10% wasn't part of the CT material. I could have sworn I'd find it in the HIGH GUARD book - but it was not to be.

 

[TheEngineer]

Hm, I'm pretty sure the 168 h +/- thing is noted in "The Traveller book". I'll check this tonight.

 

[Andrew Boulton]

LBB2 says "about a week", HG says 150-175hrs.

 

[atpollard]

I am still convinced that both the LENGTH and DURATION of a jump are determined prior to entering jump space. Just as the distance between the point of departure and the point of arrival will be different for every jump (both worlds are moving) so too the time spent in jump space will be different for every jump. The fact that the game requires a roll to determine the time does not, in itself, prove that the time is a variable and unknown quantity – it just proves that all jumps are not the exact same duration. The JTAS article clearly implies that a jump is a highly precise (if not well understood) process and it clearly states that time is a constant in jump space and the exact time a ship departs from jump space is known to the crew. Unless someone can find a passage which EXPLICITLY states that the duration of a jump is unknown before a ship enters jump space, there is no reason to believe that the jump rules and description are broken.

TE: You are correct that the “one part in ten billion” refers to the precision with which jump distance is known. I was pointing out that if the jump duration is known with the same precision, the time error is a tiny fraction of a second. In fact, if the time error is one part in ten million (1000 times greater than the distance error) then the time window is still only 1 second. If the time error is one part in ten thousand (1 million times greater than the distance error) then the time window is only 1 minute. If the time error is one part in ten (1 billion times greater than the distance error) then the time window is 16.8 hours. It seems illogical to assume that jump distance is calculated with 1 billion times greater precision than jump duration without a VERY clear cannon reference to this fact.

 

[TheEngineer]

Hi Arthur !

You're not convinced by the jump procedure reference in MTE ?

The JTAS JUmpspace article tells:

...
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.
...

Well, I have agree that so far I found no other reference regarding the temporal sequence....

Anyway, lets just assume you know the duration before jump drive engagement.
Now, could the captain just use another jump plot and look how long this one would take, and another one, and another one .... until a preferable jump plot with minimal in-jump-time is found ?
Well, this would have some impact on the TU, but such is not noted AFAIK.

It seems illogical to assume that jump distance is calculated with 1 billion times greater precision than jump duration without a VERY clear cannon reference to this fact.

Why is it illogical ?
Have a date with a girl in Your favorite bar. I'm pretty sure she will be at this place, but "when" is a question.

Hmm, the reference is given with "one part in ten billion" refering to the location in the Jumpsapce article and all the 168 h +/- variations given in the rulesets.
?

Regards,

TE

 

[atpollard]

It seems illogical to assume that jump distance is calculated with 1 billion times greater precision than jump duration without a VERY clear cannon reference to this fact.

Why is it illogical ?
Have a date with a girl in Your favorite bar. I'm pretty sure she will be at this place, but "when" is a question.

It is the assumed magnitude of the difference that is illogical without clear evidence. Using the date analogy: I can know what room she will meet me in compared to the surface area of the earth (1 part in 10,000,000,000), but if I aim for a 1 hour time slot, she could arrive up to 114 years too early or late (1 billion times less accurate than distance).

 

[ravells]

Originally posted by atpollard:
I aim for a 1 hour time slot, she could arrive up to 114 years too early or late (1 billion times less accurate than distance).

Nothing illogical about this. My wife does it regularly.

Ravs

 

[TheEngineer]

Well, it could be right, that its illogical, because there is no correleation intended by the author between location accuracy and temporal accuracy

I guess Ravs and his wife are "Highlanders"

TE

 

[aramis]

Originally posted by TheEngineer:
[Well, I have agree that so far I found no other reference regarding the temporal sequence....
[/QB]

Take a look at MT IE page 30, top left (A continuation of the Jumpspace entry on page 29). 168 ±10%

The Activity checklists (which, counter to claims, contain NO timeframes AT ALL) are on MT Ref's Companion, pages 24-25.

Now, in TTB:
Interstellar Travel, page 49. Covers passages, and gives a parsecs per week definition, with a week in jump.

Required Starship Components, page 57. Reiterates the parsecs per week.
Main Compartment: The Bridge, p 57, states the requirement for the computer to equal or exceed the JNumber. Next column states that bis models are capable of supporting a Jn 1 higher.
Page 11 states that jump is an alternate plane.

Page 147: reiterates the 1 week per jump, and that point of entry and exit can be anywhere not within 100 diameters of "any large masses."

Also, interesting:
"Another central fact of interstellar travel is the fact that no method of information transfer faster than jump drive has been discovered. Ships can carry messages, but radio lags at mere light speed. Communication is always limited to the speed of interstellar travel." (p147)


Bk5 states the 150-175 hours on page 17.
Bk5 implies that combat doesn't occur in jump on p39, since jumping is a method of escape.

TTB neither states inviolacy of J-space, nor the contrary. It provides interactions only for N-space tho.

MT IE doesn't state the involacy of a ship in J-space. It does imply it, in that there is a 6-8 day block covered in a single step, a step which is omitted in misjumps. (MT IE p92-93)

Another side note: MT RM p46 states that most worlds are self-supporting
MT RM page 59 (craft design) states: "Any jump regardless of number, takes approximately one week; ships in jumpsace are untouchable and cannot communicate with other ships or stations. Although jumps are usually made at low velocities, the speed and direction which a ship help prior to jump is retained when it returns to normal space."

 

[Whipsnade]

Originally posted by atpollard:
I am still convinced that both the LENGTH and DURATION of a jump are determined prior to entering jump space.

AT,

And you are still wrong no matter what refernces have been cited here. There is no indication in canon that jump duration is known before jump initiation. What's more, no one in canon acts or behave as if jump duration is known before jump duration.

Aramis' increasingly pathological loathing for GT has nothing to do with jump masking or jump durations in particular. He 'infers' operational attributes of jump drive that run counter to 30 years of examples throughout Traveller canon, twisting or spinning the evidence and the concensus interpretation of it, in the pursuit of a certain aim. That aim is not to remove jump masking(1) but to use such a refutation of masking as way to decanonize GT in toto.

There's an ulterior motive at work here and you needed to know it.

Sadly, Aramis' efforts founder on the one fact he cannot twist or spin. Hans Rancke-Madsen wisely reminded us all of that fact in this thread. Let me quote Han's remarks:

What makes it canon for CT is that Chris specifically asked Marc Miller how it worked and Marc gave a definite answer. The paragraph Bill quotes could just as easily be interpreted to mean that the universe only affected jumpspace near the entry and exit points, allowing a ship to jump from one side of a gravity well to the other without being masked by it. That's the way I always assumed it worked, and I don't think there's anyting in any material prior to GT that contradicts the non-existence of jump masking. But neither is there anything in that previous material that rules out jump masking. And now that Marc has explicitly introduced jump masking, I'm pretty sure it's here to stay.

So, the truth of the matter is that jump masking and all the headaches it entails are not an invention of the GT team or any GT authors. They read the same canonical passages we have and they realized, as we do, that those passages could be interpreted in two different ways. In order to solve that impass, they asked Marc W. Miller what was the correct interpretation. He told them it was the interpretation that leads to jump masking.

All other claims, charges, inferences, and readings are now moot. The man who decides what is Traveller and what isn't Traveller weighed in on this specific topic years ago.

Jump masking is canon. Period.

You're free to ignore masking IYTU, but the OTU includes masking and all that flows from it.

This discussion is over. Mr. Miller has already spoken.


Have fun,
Bill

1 - Which is something I desire.