Black holes

I remember checking some of this out once. The Traveller rules have stars
spaced approximately correctly. (Ie ave seperation in the range of a parsec
or two).

The problem is that the distribution of stellar types is such that the vast
majority of star are class M dwarfs. These require space based observatories
to locate if they are even a sector away!

At least it is fairly simple to determine stellar positions given a medium
sized (say 20 inch?) scope on a jump capable ship. Do a full 360 degree
photo survey. Do a Jump-1. Take a second set of photos. Run them thru the
computers to see which images moved and how much. Plot the positions.
Continue.

Black holes and neutron stars require a supernova to form. These require rather
large (and thankfully rare!) stars. I've seen estimates that place the lethal
radiation zone around a supernova at 15-30 parsecs. So a supernova would *kill*
a sector in all directions! The effects include what amounts to a massive
EMP. So unless your whole planet is using Fiber backup electronics...

We do have a small nebula down in the Aslan area. Except for the small
nebula ("planetary" nebulas) they tend to be sub-sector to sector size. It's
not surprising that there are so few in the mapped areas.

An old neutron star or a "brown dwarf" would have interesting possiblities.
A brown dwarf might be able to keep a small *very* close in planet warm enough
to be habitable. And it would be dim enough that it might not have been mapped.
This would make a great adventure....

"The pirate base *has* to be close! Those ships can only do jump-2."
"But there isn't anything that close..."  :-)


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<Leonard>
> I remember checking some of this out once. The Traveller rules have stars
> spaced approximately correctly. (Ie ave seperation in the range of a parsec
> or two).
Yes, but the average seperation is also in 3D space, so we are losing a number
of stars for our 2D representation. There can be many excuses for this
simplification, but as I mentioned, I assume that these other stars are not
interesting, and (for a simple model) vertical movement is unnecessary.
>
> The problem is that the distribution of stellar types is such that the vast
> majority of star are class M dwarfs. These require space based observatories
> to locate if they are even a sector away!
The charts for star creation do not give this distribution, and a viewing a
sector at a time is good data collection, unlike the core exploration rules
in the Zhodani module.
> ...Do a full 360 degree photo survey. Do a Jump-1. Take a second set of photos.
> Run them thru the computers to see which images moved...
Perhaps a Jump-6 or two would survey the area faster.
>
> Black holes and neutron stars require a supernova to form. These require rather
> ... So a supernova would *kill*
> a sector in all directions! The effects include what amounts to a massive
> EMP. So unless your whole planet is using Fiber backup electronics...
The supernova doesn't bother us if it occured 500 Million years ago, there is
no data on the density of black holes as they are so difficult to detect, there
could be ones lingering arond from the big bang (assuming you subscribe to
that theory). There could be a blackhole/neturon star in every sector, or even
every subsector without any having been formed since the time of the Ancients.

Your last point was very good...i think I'll use it in my next campaign...

		-Dan

    [email removed] 				Dan Corrin
    [email removed]				System Manager
    [email removed]         			Dept. of Mechanical Engineering
    ...!watmath!julian!engrg!dan		University of Western Ontario
"That Lame-braned freeway idea could only	[address removed]
be cooked up by a 'toon" -Eddie (Rodger Rabbit)	[phone removed]





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In response to metlay:

Oops...Yes I had forgotten about the light-bending properties of blackholes,
and with a spaceship that can move over a wide area, it is quite probable
that they would be detected fairly easily.

> ... The problem with the
> current star system generation tables is that if they reflected the true
> population distribution of stars in the primary galactic medium, they'd bore
> the average gamer to tears, because on a 3D6 table you'd need to roll a 3 or
> an 18 to get anything other than a red dwarf ... it's unreasonable to ask
> Traveller for a "more realistic" star system population distribution

Yes I agree, however I was not discussing changing the star generation process
(which I would have left on the star generation list), rather coming up
with a reason for the generation as listed. I did want a sub table to
generate other stellar phenomanon used perhaps once or twice per sector.
The rules (scouts) even mention adding supergiants in at a very low density
(1 per sector or so).

My main points are/were:
1) Stars not represented correctly (2D, too many non-dwarf, no black holes...)
a) Assume all stars are projected into a plane. to get 2D board
b) a large number of stars are not mapped (usualy dwarfs) because of no
bodies in the system for bases/fuel.
c) Resultant stars provide density and composition we get from the star
generation tables. (I have a good reason for 2D as well which I haven't
brought up).
d) Add in other interesting stellar objects at a rate of a few per sector
(I like a lot of black holes myself...but see first paragraph).
e) this results in no changes to the maps (execpt where you want to mark
other stellar objects), nor to any rules, it is just a method of
perceiving the traveller universe so that it approximates ours more closely
(after all we have already assumed a 2D universe)

2) Obervation techniques don't seem to match today's standards.
a) Correct me if I'm wrong as I havn't dug up my Zhodani alien module, but
I believe that in the core exploration rules, you only get to see an
area 2-3 parsecs ahead of you.
b) if you subscribe to (1) above, identifying good stars may that difficult.
c) if not, (I was probably exaggerating when I said we could see the entire
imperium from one location.) but even the near star map at 50 ly radius
represents a circle with a 30 parsec diameter, which is approximately a sector
(24x40 parsecs). That is with tech 8 ground based telescopes, a good TL 15
scout in space with no light noise sould get at least 4 sectors. (double range)
d) additionaly as an jump-capable observer can more easily calulate positions
by virtue of being able to observe from different points (from Leonard)

	-Dan

BTW I haven't received any mail ([email removed]) complaining, so I will
continue this discussion on the list.


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[This came to [email removed], looks like it was
meant for [email removed].  Watch those automatic reply
headers! -- James]

[email removed] writes
>In response to metlay:
>
>Oops...Yes I had forgotten about the light-bending properties of blackholes,
>and with a spaceship that can move over a wide area, it is quite probable
>that they would be detected fairly easily.

Actually, at distances of parsecs, the light bending properties of black
holes are not significantly different from those of ordinary stars of the
same mass.  I won't bother you (unless provoked!) with the math, but the
point is that the Einstein ring diameter (=characteristic scale of lensing
phenomena) is far larger than the stellar radius so that it makes very
little difference whether the mass is concentrated within its
Schwarzschild radius or merely within a normal stellar radius.  The
differences get more impressive if you get close (say within about 0.01 pc).

On the general topic of stellar exotica in Traveller, one should not
overlook degenerate (white) dwarf stars which are certainly common enough
to appear in great numbers within the Imperium.  Although much less
exotic than neutron stars and black holes, their large surface gravities
and tendancy to produce enormous explosions (novae) when provided with a
bit of hydrogen fuel might allow for some interesting adventures.  BTW,
such stars often occur in binary systems which would allow for an
ordinary star supporting habitable planets in the near vicinity of a
degenerate dwarf.

Ed Turner


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Administrator: [email removed] (James Perkins)
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