Re: [asa] Rudwick does it again (back to Adam)

George Cooper wrote:
>
> [Don, I get about 0.87 miles for a 1.5 inches of sinking between them
> when they are at sea level. ]
>
>
>
> Coope
>
Maybe my earlier corrections on this weren't seen, but a two-meter tall
person could see about 3 miles (5060 meters) to the horizon on an
earth-sized sphere. Hence the inability to see an opposite shore line
on a lake more than 3 miles across. (disregarding refractive effects.)

Or the 1.5 in. height George notes above would have a horizon about 0.43
miles away, or you could get the 0.87 mi figure as the distance apart
that two 1.5 in. tall figures could see each other over the horizon
'hump' centered between them. But on that scale, even the slightest
waves overwhelm any precision. And for longer and larger heights &
distances refraction, atmospheric haze and such begin to impose their
limitations. But for intermediate distances, such as over a large calm
lake this effect is actually quite observable --especially with a good
pair of binoculars.

(When I email from school it comes through under mrb22667@kansas.net
--I hope those emails have been getting through.)

--Merv

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Received on Thu Aug 21 20:06:21 2008