[FT] Islamic Federation ships and request to Nyrath

[quoted original message omitted]

> On Sun, 22 Aug 1999, Laserlight wrote:

> From: John Atkinson <johnmatkinson@yahoo.com>

i'm not entirely sure which lines are from John and which from Laserlight,
but i think i'm arguing mostly with John - just like the good old days
:).

> >> contrast this to the >tug-and-lighter setup, where your

on a military ship, yes. civilian ships are somewhat less stressful, and it is
readily possible to replace most of the crew: only the skipper, chief
engineer, purser, etc have to stay with one ship, and they can rest up during
slack time or maintenance layovers. and, yes, that is pretty tough, but that's
pretty much how things are in the merchant navy today
(i
think).

> >>it's interesting that this breaks down for longer > trip

ym Alderson points. all my points are good for is stirring up arguments
:).

> >instantaneous, but slow within system, to the point that

iirc, in the Tuffleyverse, jumps are instantaneous and not restricted to
jump points - a ship can travel from any point outside a jump limit to
any other such point under FTL alone, making many jumps. thus, it can
essentially follow a straight-line course.

> (I'd have a station on each side of the FTL transit point.

this is functionally equivalent to a jumpgate, and is similarly only
economical if you have sufficient traffic through that one jump point -
it probably would be in the jump points in an industrialised system, but
unless you have a high density of developed systems, it is probably not
profitable in undeveloped en-route systems.

in the Tuffleyverse, since there are no jump points, this particlar
arrangement is not really feasible. however, you might have a shipping firm
operating a tug liner service between two fairly close stars, so that ships
rendezvousing with the tugs are lifted into the other system, much as the
channel tunnel trains carry cars between London and Paris.

nb: i mean liner in the technical sense - a ship which repeatedly goes
between two or more) fixed points (like the Earth - Moon helium
tankers), as opposed to a tramp, which travels about as contracts take it.

since this sounds like a good wheeze, i think i'll mention it in my Dutch
economic history.

> >Also, can I reserve a star for Uusi Soumi?

the name rings no bells, unless it's a misspelling (or a respelling) of Suomi,
meaning Finland. care to elaborate?

> > Tidelocked dirtball with no surface water and a

i wouldn't say that north and south are meaningless, and as for living
'slightly dark of the equator', i think you may have your wires crossed.

basically, a tide-locked planet is like a normal planet on which it is
always the same time of day at any given place. thus, 'darkward' and
'lightward' have the meanings that they do during dawn or dusk on a normal
planet: at dawn, light is east and dark is west, vice versa at dusk (provided
the planet spins anticlockwise when seen from above the north pole, as Earth
does). thus, lightward and darkward are parallel to east
and west; since the equator runs east-west, you can no more be 'slightly
dark of the equator' than you can be slightly north of the Greenwich meridian.

note that on a tide-locked planet, there are two regions of twilight, on
the border between the dark and light sides, which correspond to the dawn and
dusk regions on a normal planet (it's just that the day is a year long, and so
the terminators move at the same rate the planet is turning under them). thus,
the two regions will have different mappings of
light/dark to east/west; the situation would be analogous to the
big-endian vs little-endian conflict in 'Gulliver's travels'.

tom

> Tom Anderson wrote:

> basically, a tide-locked planet is like a normal planet on which it is

Try a tide locked planet where due north points at the sun. Wait, you say this
can't happen. Well, it doesn't have to be tidelocked to the sun...

NB. Sun refers to the star that provides energy for the system.

> On Mon, 23 Aug 1999, Roger Books wrote:

> Tom Anderson wrote:

or where due south points directly at the sun all the time; i say we do
this - give that m*********ing grinning mountie b*****d what for ... :)

> Wait, you

if it's not tide-locked to the sun, then it's sort of pointless. i did
consider end-on planets (like uranus, iirc), but i concluded they
weren't worth mentioning; i can't remember why, but i think it was partly
because they're rare (probably).

in any case, if a planet is end-on, it has permanent night and permanent
day areas, just like a tide-locked planet, even if it isn't tide-locked.

also, John A replied to my email and pointed out one or two holes in it.
firstly, north and south are obsolete not because they encode no geographical
information, but because they encode no climatic information,
as the light-dark climate difference overwhelms the north-south
difference. secondly, there are not, as i stated, two regions of twilight, but
one band of constant width encircling the planet; this can be split into two
halves according to whether it's dawn or dusk, but that's not really
important. so, whilst i was not wrong, John was more right:).

i do have answers to these points, though. i'll send my reply on to the list.

tom

Tom A said:

> in any case, if a planet is end-on, it has permanent night

No. A tide locked planet (tide locked through the north pole, say) would
present the north pole to the primary at all times. A planet which is (as Tom
puts it) "end on" would present the north pole in the same direction all the
time, but in reference to the universe at large, not the primary (in the same
way the Earth's pole always points towards Polaris).

> On Tue, 24 Aug 1999, Laserlight wrote:

> Tom A said:

i'm evidently not having a good day today.

Roger wasn't referring to this case, though: he specifically said "it
doesn't have to be tide-locked to the sun". but still.

i am having a slightly hard time imagining a planet with spin axis
parallel to the ecliptic and which is tide-locked to the sun: it would
involve the axis changing direction relatively rapidly (a comlete circuit once
a year). this means that the tidal force on the planet is enough to overcome
the precession effect due to the planet's angular momentum (my physics being
rather lacking, i lack the words to describe this properly).

given the size and mass of a planet, that is a very large amount of momentum,
and consequently would require huge tidal forces. i'd be skeptical about such
a configuration being possible for a planet of habitable size (although i have
a very strong suspicion i'm about to be proven wrong!).

tom

> On Wed, 25 Aug 1999, Tom Anderson wrote:

> worth mentioning; i can't remember why, but i think it was partly

1 out of 9 isn't that rare in my book.

> in any case, if a planet is end-on, it has permanent night and

No not permanent night and day, just about practically that... the length of
the siderial (one "solar cycle") period will be the length of one complete
orbit as the planet's pole will most likely be pointed in the same direction.
Of course the planet could precess.

> also, John A replied to my email and pointed out one or two holes in

depending on the distance of the planet to the star (stars?) this could make
it quite inhospitable in certain areas. There was a book called Diary of a
Space Person that among other things spoke of a planet that had Cities on
rails that worked their way around the planet to keep on the edge of the
twilight and at a steady hospitable temp. Crews would range ahead and fix any
damage to the rails that had occurred over the "night". If a city was unable
to progress due to a system outage, it would be blown off the tracks to allow
the other cities to pass....tough

luck for those in the city ahead of everyone else....:\

Ryan pens:
> On Wed, 25 Aug 1999, Tom Anderson wrote:

You're working with small number statistics here. With this small a sample,
and considering how said planet ended up being tilted, I'd call it reasonably
rare, if not fairly uncommmon.

You can probably extrapolate by examining the moon systems of the gas giants,
applying what you find there to planets around other stars.

Mk