bent light & horizon

From: ian (i.) gorlick (
Date: Thu 22 Feb 1996 - 23:51:00 EET


I think I see where you are making a wrong assumption in your geometry. The
light from the top of the wall does not have to start off parallel to the
ground, it can start with a slightly downward trajectory so it approaches the
ground and then is on the upswing when it hits the observer's eyes. Light from
the base of the wall MUST start parallel to the ground or with an upward
trajectory, so it swings up sooner and passes over the head of the observer.

A flat surface and upward curving light should look almost indistinguishable
from a downward curved surface and straight light in near and moderate
distances, it will have weird effects for astronomical observations where the
distances are very large and the curvature becomes extreme.

Brian Curley's friend:

the discussion is mostly sound but there is one small bit of confusion. Optical
signals (mirrors, fires, flashlights) are still aimed directly at the desired
target. The light you send at the target will retrace the exact path of the
light coming from the target, so you still aim exactly where you see the target
to be.

There will be a need for interesting corrections for long-range artillery. I
would put this in the same category as Coriolis (sp?) force corrections in our
own world.

At the relatively short ranges achievable with bows and catapults, there should
be no measurable effect IMO.


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