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# CONCULTURE: First thoughts on Ayeri calendar system

From: Simon Richard Clarkstone Monday, November 15, 2004, 1:46
```Carsten Becker wrote:
> So for the time being, I thought it would be quite
> interesting to have two moons -- though I haven't done my
> homework about how long the moons' cycles must be and how
> far they are away from the planet etc. etc.3-body systems are chaotic and hence (in the general case) not stable.
Generally, the smallest of the three bodies ends up either hitting
something or getting flung away.  One _can_ have a reasonably stable
system if either:
* There is one huge body with much smaller bodies orbiting it. (e.g. the
solar system)  Both  moons would be too small to be easily seen.
* two bodies orbit each other closely with one much further away. (e.g.
the sun-moon-earth system)  Either one moon would be too small/far away
to be easily seen, or the moons would form a pair, and hence stay close
to one another in the sky (interesting but not what you are describing).

> Without any
> scientific justification, I assumed Moon A to have 24-day
> cycles and Moon B to have 60-day cylcles. Furthermore, I
> assumed that the moons both have irregular orbits, like
> when drawing something with the Spirograph if you know that
> thingy.The act of causing tides tends to make orbits
a) more circular
b) larger (energy is lost, so the moon recedes, as ours is)

> So Moon A needs ~1/4 year (455.75/4 = 113.9375
> days) to be at the same position where it started and Moon
> B needs ~1/2 year (455.75/2 = 227.875 days) for that. These
> second cycles s/would be best called "big cycles" I guess,
> the month cycles "small cylces".
>
> Distinctive points then would then be (S = sun; P = planet;
> A = moon A; B = moon B; yrs = years; ds = days):
>[large diagrams snipped]

I can see a problem brewing here, though there is nothing _per se_ wrong
with the above.  In general, make sure you know whether you are
measuring positions/angles relative to the fixed stars, or relative to
some existing line (e.g. planet-sun).  Find an astronomer to help with
all the difficult bits, being at university helps. (but I don't even
know if you're 8 or 80)

> That would mean there'd be a lunar and/or solar eclipse
> every quarter year?No.  That would only happen if the orbits of everything were exactly on
a plane.  In practice, the planes of all the orbits are slightly
different, so thing come (apparently) close to each other, but do not
eclipse.

--
Simon Richard Clarkstone
s.r.cl*rkst*n*@durham.ac.uk / s*m*n_cl*rkst*n*@hotmail.com
```