more moonlighting

From: ian (i.) gorlick (igorlick@bnr.ca)
Date: Fri 23 Feb 1996 - 19:21:00 EET


Martin:
>If there is a horizontal axis relative to the surface of Glorantha, then
>there will be observers directly "north" and "south" of the axis. These
>people will observe an approximately half moon endlessly rotating diesel or
>widdershins. Hardly a true phase progression.

That is what they would see IF light moved by straight lines. My proposal is
that because of large curvature of the light, they will only see the side of the
moon that faces down, not the side that is geometrically towards them. The bent
light has the effect of apparently rotating the lower face of the moon towards
all observers anywhere on the surface. Or alternatively, you could think of it
as the bending of light makes the moon appear like a much larger object that is
much further away; if it is far enough away then everyone gets the same view of
it.

If one can observe the pole then one will not see proper moon phases. You are
correct. That is one reason why I don't like the vertical axis theory. People
inside the empire close under the moon (where the lunar way should be strongest)
will not see the most characteristic lunar phenomenon of phase changes. Only
those distant from the moon would see proper phases.

Nick:
Sorry if I sounded a bit testy. Now about your latest response:
> I think the best way to
>explore the theory is by looking at celestial phenomena and working out the
>curved-light explanation for why they look the way they do: not (as you seemed
>to be doing) to say that the Red Moon must appear weirdly distorted because of
>the theory. I think we can safely say she looks round from the ground.

Does she look round everywhere? Remember, the degree of distortion could be
fairly small, I haven't got enough data to really do calculations on how oblate
she would appear. From inside the empire she could appear perfectly round to
within limits of observation, but from far enough outside there could be a
detectable distortion. Maybe one of the effects of the Glowline is to alter the
curvature of moonlight so that she does appear more perfect inside, the
shimmering glowline might be caused by the change in refractive index for
moonlight at the border. (This is only a wild speculation, not a serious
suggestion at this time.)

As you have said, there are contradictory sources about the appearance of the
moon at this time. Are we sure that people outside the empire do see the moon as
a perfect sphere? Yes, I have no evidence that the moon does appear distorted
when viewed from Sartar; but I have an optical theory that says it might and I
have a good religious/cultural reason why the Sartari would like to see a
distorted moon. And I can still explain why the Lunars see a perfect moon. I
think it is a good fit.

>There's enough weird effects in the Gloranthan Sky to be getting on with, IMHO,
>without making us all put on thinking caps every time we want to look at the
>sky

I'll grant that thinking through weird physics may not contribute to MGF for
many people. If curved light is too hard to handle then it should be rejected. I
don't think it is really that complicated. You liked my description of the sun's
apparent motion, and some people liked the appearance of the moon. That is as
complicated as it gets. If you can get your mind around those two examples you
should be able to handle everything.
at night.

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