Bent Light and a bit about Nick...

From: Dane 'Danger' Johnson <dane_at_frame.com>
Date: Tue, 20 Feb 1996 11:53:00 -0800


Nick, in an impassioned plee for tolerance, characterizes himself as:

>that racist, chauvinist, bigoted xenophobe (and effete,
>decadent shirt-lifter; not to mention demon-worshipping Satanist) Nick Brooke.

You forgot Unwashed and Hairy... :) I must, however, plead ignorance about the term 'shirt-lifter'. Not that this is particularly relevant to Glorantha.


Ian, in a post about what Moons look like, presented the following interesting fact and question:

> Add to this the known
>fact (Greg imparted wisdom) that light on Glorantha does not travel in
straight
>lines, but rather curves upward because of its afinity to the sky, and you
soon
>come to the conclusion that only the lower face of the moon can be seen from
>anywhere on the surface world.

[Snip]
>I think there must be other interesting effects due to the bending of light.

The thing which occurs to me about this, right off the bat, is that if Light is really going to curve up towards the sky, then Glorantha will have a horizon even though it's flat. All we have to do is tip Ian's triangle with the moon on it's side.

Consider a man standing in the middle of the Wastes of Prax. He looks out over the desert. Light from some distance away streams towards him, but in a curved path, attracted by it's affinity to the Sky Dome.

Light coming off of the nearby shrubs will be moving mostly straight, both because the "source" of the light is close (and so the light hasn't risen much towards the sky yet) and because the amount of curvature in the light's path can't be too weird, at least under normal circumstances (assuming, of course, that Glorantha light is at least similar to Earth light in most respects and that vision works more or less the same way).

Light coming off of a Morocanth standing, say, a mile away will be rather more curved. The light which the man uses to actually see the Morocanth travels in a curved path from the Morocanth to the man's eyes. Light leaving the Morocanth in the direction of the man would curve up and away into the sky, missing the man's eyes. Instead, the light the man uses to actually see the Morocanth would be that light which travelled somewhat more parallel to the ground, to begin with.

Really, it's like trying to make a basket in basketball. Instead of curving the ball overhand, however, because gravity pulls it down, you have to pitch it underhand, because the Sky Dome is pulling it up.

Anyway, my point is that, eventually, something will be far enough away from the man that all the light coming from it has been pulled up into the sky, and none of it hits the man's eyes and he can't see it. The closest point at which this happens would be the Horizon. Standing up higher allows you to see beyond this horizon, because by raising yourself up you'll be able to catch some of the light which was passing over your head...

Of course, this might make for some strange optical distortions of distant objects (it would tend to make it look like you're standing at the bottom of a bowl -- by looking straight ahead, you'd be picking up light from the 'ground' at the horizon. Also, the first thing visible about something crossing the horizon would be the part of it close to the ground, since light coming from above that point would be missing your head...), AND it assumes generally Earth-type vision and physics. Still, it is interesting....

Dane


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