Next message: Fred Hebard: "Re: Mirages, was: Refraction"
Fred,
An image sunk below the horizon could not be seen and thus could not be
an image. However, I think what you are getting at is a converse of the
classic mirage seen in hot, desert areas.
Low-latitude mirages involve light rays bending upwards very near the
ground, so that we see light from the sky apparently rising from the
ground. But high-latitude mirages involve the reverse bend, so that
surface light appears to come from the sky. They are perhaps most common
in the form of "ice blink", where sunlight reflected off ice beyond the
horizon is visible as a whiteness in the sky. However, there are reports
of people seeing, in the sky, inverted images of ships which, in
reality, are hull-down over the horizon.
I have characterized the two types as "low" and "high" latitude but they
are, of course, respectively the result of (1) intense solar heating of
a land surface under cooler air and (2) the presence of warmer air
overlying a very cold surface.
Trevor Kenchington
Fred Hebard wrote:
> OK ladies & gentlemen. We have the case of a mirage, where the image
> rises above the desert floor. Are there any counter examples of an
> image sinking below the horizon?
--
Trevor J. Kenchington PhD
Gadus Associates, Office(902) 889-9250
R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251
Nova Scotia B0J 2L0, CANADA Home (902) 889-3555
Science Serving the Fisheries
http://home.istar.ca/~gadus
