Re: Fw: [FT] Islamic Federation ships and request to Nyrath

On Mon, 23 Aug 1999, Roger Books wrote:

> Tom Anderson wrote:
> 
> > 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.
> 
> Try a tide locked planet where due north points at the sun.

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
> say this can't happen.  Well, it doesn't have to be tidelocked to
> the sun...

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