Re: CONCULTURE: First thoughts on Ayeri calendar system

Sylvia Sotomayor wrote:

> On Monday 15 November 2004 10:36, Chris Bates wrote:
> [more moons & planets & orbits & tides]
>
>>different, perhaps you should have no moons? A world without tides and
>>without the moon at night would be interesting. :)
>
> I've thought about that, too. But, if the Earth didn't have the moon, we'd
> probably have 10 hour days, very high winds, all sorts of "unearthly"
> weather, and probably far far more meteor craters.
More importantly, we wouldn't have much complex land life, because the
Earth's angle of tilt would vary more.  Our Moon significantly increases
the stability of the Earth's angle of tilt.

[snip]
> Anyway, extra high tides would be a good reason for all my Keleni to live
> inland, though I suppose that with enough mass, any lunar system could
> noticeably effect lakes and rivers, too.
I'm not so sure about this.  In Earth's open seas, tides are only a few
cm verticaly.  What is important is the horizontal shift of water.  A
very rough example follows to show why, with my best understanding:

Suppose, in a 10km-wide strip of 10km-deep sea, the water shifts down
3cm (wild guess).  This makes it 3cm wider.  All the sea next to it must
move 3cm sideways to make room, and so on across the ocean.  But at the
coast, the sea might be only 0.1km deep.  Then, to move the same volume
of water, the sideways shift is 3m.  Thus, is a 1km-wide strip of
coastal water (of any depth) will shift 3m up.  Thus, the tides are much
bigger on Earth's coasts than they would be on a planet with deep seas
all over.

Also, tides are (mathematically) waves, so they can bounce off coasts,
producing unusual effects:
<http://www.quoddyloop.com/tides.htm#wonders>
Also, the real explanation is far more complicated than my summary above:
<http://www.linden-software.com/Explanation.html>

On a lake (except maybe a huge one), the water would not be deep enough,
and the difference in the Moon's gravity on the opposite sides of the
lake would be very small, so tides would be small to non-existent.

BTW, A tidal section of a river is the (only) British definition of
"creek".  The apparently wider American usage does not apply, AFAICT.

There you have it; more than you ever wanted to know about tides.  If a
conlang/conculture course were taught in University, it would cover a
wider _range_ of material than any other (though not in as much depth).
--
Simon Richard Clarkstone
s.r.cl*rkst*n*@durham.ac.uk / s*m*n_cl*rkst*n*@hotmail.com