Real-universe jump distances

[aramis]

@Aramis: Did you get the impression that he meant that not all systems are on it because some systems are unimportant (i.e. nobody generally has a reason to go there, so they are no on the map), or that some systems are not on it because they are unreachable by Jump? If the latter, is there only a single "Jump Plane", or are there effectively a large number of planes based upon the angle of Jump initiation relative to the galactic plane (i.e. are there alternate distinct Jump planes, for example, along perpendicular or 45^o angles to the galactic plane as compared to the "standard plane" parallel to the galactic plane?

There is one jump plane. It's not exactly flat, and systems not on it are accessible only via sublight.

 

[aramis]

Objects larger than the ship can pull it out of jump...
So I'm going to guess that this doesn't mean larger ships, as that would really mess up jump travel throughout the galaxy, particularly if a 100-ton Scout and a 2,000-ton Carrier were headed to the same place at the same time.

No, larger ships are explicitly included. Any solid or liquid body, even if hollow.

I'm assuming that this means astral bodies not known to be between the entry and exit points: a comet with a particularly long orbit, an asteroid knocked into a previously-clear jump route, a rogue planet, a stellar ignition or collapse, and so on.

it also includes ships in N-space for various reasons.

I've played this up before, having Travellers on the way to a given system only to "fall out" of jump because of high-energy spatial anomalies, a rogue planet, and even an previously unknown Dyson shell.
Now I don't claim to know if that's actually what Mr. Miller meant, but it works well in my games, particularly when you want to introduce something to temporarily sideline the Crew (for whatever reason).
Just a thought.
mactavish out.

In your games, do what you want.
In the OTU, big ships can pull little ships out. Marc hasn't cleared up the issues of if it's only at entry and exit times, or any time during the week.

 

[whartung]

A course plot is 162:00:00±16:12:00 H:M:S
Ships sharing a course plot vary by ±1:37:12 from each other.

Just for others sake, as I had to do the math. The time discrepancies are 10% and 1%.

Courses can be reverse engineered in a few hours if the exit flash is captured on sensors.

So, if observed on entry, it can be computed as to which system the ship original jumped FROM?

Everything bigger than the ship can pull it out of jump.

So, if all of the system listed on a subsector map share the Jump Plane, and Jump is effectively 2-D, does that suggest that when a ship jumps, they are on a straight line course from entry to exit, effectively "under water", for lack of a better concept? and "going really fast".

That is, for example.

If you have Jump 1, 1 Parsec. 3.26 light years. Jump time is 162 hrs (for this discussion, we'll ignore the plot variance). So, 3.26 LY / 162 hrs is ~0.02 LY/hr. That's 189,216,000,000km/hr, or 5,2560,000km/s.

So, let's say there's a 1000 ton ship, out by Jupiter, that Just So Happens to be In The Way. Jupiter is 588Mkm away, so, that's ~100s away at 5.2Mkm/s.

Does the ship precipitate back out of jump a week later? or 100s later?

More importantly, when does the larger ship have to be "in the way". Does it have to be there at the 100s mark? What happens if it crosses 3 days later?

That's quite a adventure seed of a ship trying to get away finding itself a week later popping out in the outer system, in the "middle of nowhere" since the ship that popped it out has been long gone.

But, no doubt these are some of the nits that you're trying to clarify.

 

[aramis]

Just for others sake, as I had to do the math. The time discrepancies are 10% and 1%.



So, if observed on entry, it can be computed as to which system the ship original jumped FROM?

I've a bad habit of describing jump out as exit. From the source, you can calculate the destination, and follow. The source is implied by your exit motion... except that in T5, non-gravitic thrusters can change your N-space vector during jump...

 

[Grav_Moped]

No, larger ships are explicitly included. Any solid or liquid body, even if hollow.

it also includes ships in N-space for various reasons.
In your games, do what you want.
In the OTU, big ships can pull little ships out. Marc hasn't cleared up the issues of if it's only at entry and exit times, or any time during the week.

Going through my post history, forgot this one.

Other than it being Word of Marc, it snaps my disbelief suspenders.
The logical effect (if it exists) shouldn't be to yank the smaller ship back to the starting point, but instead to force the smaller ship to have misjumped (since it initiated Jump within what turned out to have been within the 100D limit of the larger ship, though it wasn't when they left).

 

[aramis]

Going through my post history, forgot this one.

Other than it being Word of Marc, it snaps my disbelief suspenders.
The logical effect (if it exists) shouldn't be to yank the smaller ship back to the starting point, but instead to force the smaller ship to have misjumped (since it initiated Jump within what turned out to have been within the 100D limit of the larger ship, though it wasn't when they left).

You're not the only one. I pointed out that it's actually a drastic change to the OTU.

It does, however, give a reason for battleships...

 

[Grav_Moped]

That it does.

But you don't need a battleship.
"Any solid or liquid body, even if hollow."
How about a 250m diameter mylar balloon, inflated with hydrogen vented from a ship's fuel tank?

 

[Ulsyus]

Also doesn't Near Stars use some sort of hypothetical dim stars or something to allow for Jump-1 usage?

No. Not in the original one T:2300 NSL. They used a 7.7 LY limit for the drive. Avoids that.

It's out on the fringes that they added some in a supplement - but it was because they wanted a Kafer arm

That reference was in the second Kafer campaign book. It involved using a brown dwarf as a navigational/Stutterwarp-charge-dump point midway between an system in the American Arm and a point way down a route inside Kafer space on the far side of the Kafer/Human front line at the end of the French Arm.

I've wondered at times why brown dwarf stars and any attendant planets, or even rogue planets out there between star systems, weren't used more in Traveller, but I suppose that except for in the Rift they aren't that necessary once J3 and higher is available.

 

[BwapTED]

Objects larger than the ship can pull it out of jump...

So I'm going to guess that this doesn't mean larger ships, as that would really mess up jump travel throughout the galaxy, particularly if a 100-ton Scout and a 2,000-ton Carrier were headed to the same place at the same time.

I'm assuming that this means astral bodies not known to be between the entry and exit points: a comet with a particularly long orbit, an asteroid knocked into a previously-clear jump route, a rogue planet, a stellar ignition or collapse, and so on.

I've played this up before, having Travellers on the way to a given system only to "fall out" of jump because of high-energy spatial anomalies, a rogue planet, and even an previously unknown Dyson shell.

Now I don't claim to know if that's actually what Mr. Miller meant, but it works well in my games, particularly when you want to introduce something to temporarily sideline the Crew (for whatever reason).

Just a thought.

mactavish out.

Charted space lanes!


Maybe this is another reason why they exist: to prevent ships in Jump from pulling other, smaller ships out of Jump.

Space is very big. Just don't aim at the same point.

Stay in your lane. :0

 

[Grav_Moped]

That reference was in the second Kafer campaign book. It involved using a brown dwarf as a navigational/Stutterwarp-charge-dump point midway between an system in the American Arm and a point way down a route inside Kafer space on the far side of the Kafer/Human front line at the end of the French Arm.

I've wondered at times why brown dwarf stars and any attendant planets, or even rogue planets out there between star systems, weren't used more in Traveller, but I suppose that except for in the Rift they aren't that necessary once J3 and higher is available.

Some calibration points and a "rogue star" have recently(?) appeared in Reft and Corridor sectors, denoted by red crosshairs. I'm not sure when they were added or why (do they come from the novel?) but they weren't there when I looked last year.

 

[whulorigan]

Some calibration points and a "rogue star" have recently(?) appeared in Reft and Corridor sectors, denoted by red crosshairs. I'm not sure when they were added or why (do they come from the novel?) but they weren't there when I looked last year.

Rogue Star was first mentioned in one of the MgT1e sourcebooks ( I don't remember which off hand), but was fixed in location by MgT: The Great Rift. Most of the other calibration points in Reft have a similar history, although some are mentioned at least as early as the TNE era.

 

[JimMarn]

Rogue planets, and likely stars to, may be more common than astronomers originally thought. Sometimes when I am watching 'How the Universe is Made' on Discoveery, one of the astronomers will mention them. The possible numbers are unknown.

 

[Grav_Moped]

Rogue Star was first mentioned in one of the MgT1e sourcebooks ( I don't remember which off hand), but was fixed in location by MgT: The Great Rift. Most of the other calibration points in Reft have a similar history, although some are mentioned at least as early as the TNE era.

Thanks!

 

[faherman]

Height & depth of jump plane?

There is one jump plane. It's not exactly flat, and systems not on it are accessible only via sublight.

Sorry for the necro, but is there any official word on about how thick the jump plane is? If not, does anyone know (or does anywhere name) the highest jump-reachable star "above" the galactic equator, and the lowest jump-reachable star "below" it?

 

[JimMarn]

I don't remember exact distances, but I vaguely remember some of the globular clusters in the galactic halo are significant distances away from the nearest galaxy solar system.

These links might help. I didn't see actual distances on the first one.

https://en.wikipedia.org/wiki/Globular_cluster

This list gives location in our sky, but not distances from our galaxy.

https://en.wikipedia.org/wiki/List_of_globular_clusters


edit: hard to read for me light gray letters on a dark gray background, but this page has distance from our solar system and the galaxy core. I would think one of the measurements would be 'distance to the nearest part of the Milky Way galaxy' but they didn't do that.

http://www.deep-sky.co.uk/observing/palglobs/palglobs.htm

According to one page I looked at, scientists have just recently measured the distance to a few globular clusters.

 

[faherman]

Height & depth of jump plane?

I don't remember exact distances, but I vaguely remember some of the globular clusters in the galactic halo are significant distances away from the nearest galaxy solar system.[/url]

Oh, certainly. But I'm wondering specifically in regards to the Jump Plane aramis refers to Mark Miller talking about upthread, which if I read him right means a specific not-very-thick "horizontal" slice through the galactic disc that contains all the stars reachable by Jump. That is, where I've generally assumed that Traveller maps are flat rather than 3D because otherwise you'd go crazy trying to make them work, aramis/Miller seem to describe an *actual* 2D Jump Plane within which Jump drive works, with there actually being stars above and below the plane that Jump simply can't reach, but a sublight starship could (eventually). So I'm asking if this Jump Plane's horizontal thickness has ever been established anywhere, and or if any (ideally real-world) star named in Traveller is known to be the highest or lowest within it?

 

[whulorigan]

I don't remember exact distances, but I vaguely remember some of the globular clusters in the galactic halo are significant distances away from the nearest galaxy solar system.

Oh, certainly. But I'm wondering specifically in regards to the Jump Plane aramis refers to Mark Miller talking about upthread, which if I read him right means a specific not-very-thick "horizontal" slice through the galactic disc that contains all the stars reachable by Jump. That is, where I've generally assumed that Traveller maps are flat rather than 3D because otherwise you'd go crazy trying to make them work, aramis/Miller seem to describe an *actual* 2D Jump Plane within which Jump drive works, with there actually being stars above and below the plane that Jump simply can't reach, but a sublight starship could (eventually). So I'm asking if this Jump Plane's horizontal thickness has ever been established anywhere, and or if any (ideally real-world) star named in Traveller is known to be the highest or lowest within it?

Deneb^* lies 15.1pc above the parallel galactic-plane in which Terra lies.
Antares lies 44.2pc above the parallel galactic-plane in which Terra lies.
Muphrid (Aqilat/Bansadan/SolomaniRim) lies 10.9pc above the parallel galactic-plane in which Terra lies.
Arcturus lies 10.6pc above the parallel galactic-plane in which Terra lies, and is ~1.0pc distant from Muphrid.

^* - Note that Deneb on the Traveller Map lies at half its actual horizontal/planar distance from Terra compared to reality. It should be on the coreward edge of the Zhodani Consulate.​

 

[77topaz]

"It is known that there is an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the universe can be said to be zero. From this it follows that the population of the whole universe is zero, and that any people you may meet from time to time are merely the products of a deranged imagination."

I'd just like to point out that the bit I've highlighted isn't really mathematically correct: infinity with some finite number subtracted from it is still infinity, and even a fraction of infinity is still infinity (Hilbert's paradox of the Grand Hotel helps with visualising these sorts of things), so not all of the infinite number of worlds being inhabited does not necessarily imply the number of inhabited worlds is finite.

 

[faherman]

Deneb^* lies 15.1pc above the parallel galactic-plane in which Terra lies.
Antares lies 44.2pc above the parallel galactic-plane in which Terra lies.
Muphrid (Aqilat/Bansadan/SolomaniRim) lies 10.9pc above the parallel galactic-plane in which Terra lies.
Arcturus lies 10.6pc above the parallel galactic-plane in which Terra lies, and is ~1.0pc distant from Muphrid.

^* - Note that Deneb on the Traveller Map lies at half its actual horizontal/planar distance from Terra compared to reality. It should be on the coreward edge of the Zhodani Consulate.​

Hey, thank you! That suggests that the Jump Plane is somewhere around 45-50 pc thick, and Sol is somewhere near the "bottom" of it...

 

[JimMarn]

Saw a documentary that included our solar system movement a few years ago.

Don't remember the time frame, but as we orbit the galaxy, our solar system moves below, even with, then above the galactic ecliptic.

Hmmm. By time frame, I don't remember how long it takes to go from max below to max above. Likely over thousands of years.