lazarus@athena.mit.edu (Michael Friedman) (02/27/88)
In article <3818@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes: >In this article I will show my calculations which show that, >if my calculations are correct (and I urge all interested to >check them), Michael Friedman must have been blatantly *lying* >when he claimed: > >>}In article <3060@bloom-beacon.MIT.EDU} lazarus@athena.mit.edu >>}(Michael Friedman) writes: >********************************************************* >* >}\I actually stood on the beach in Key West and >* >}\saw Cuba off in the distance. Think about that. >********************************************************* I. Re vision, I wear glasses. The wonders of modern science being what they are, myu corrected vision is something like 20/10. II. What do I know? I was in Key West for almost a month. We had been told that on a really clear day you could sometimes see Cuba. Therefore, on a beautiful sunny morning we went down to the sothern tip of the island and looked out. There, on the horizon, in approximately the right place, was something that can best be described as a smudge. We assumed it was Cuba. >What we are calculating first is the length of the line >from the center of the Earth to the line of sight. >This is 3,963.2/.9998 = 3,963.59 miles We need another digit here. The difference between .99980 and .99989 is large enough to matter. >.39 miles * 5280 feet per miles = 2059 feet >I.e. Cuba *could* conceivably be visible, given the >Earth's curvature and assuming miraculous visual acuity >*IF* it had a mountain 2059 feet high. >My conclusion: >it was absolutely *IMPOSSIBLE* even given a telescope and >rightwing "Vunderkind" miracle vision of the Pat Robertson/ >Ronald Reagan sort to see Cuba standing on the shore of >Key West. As far as I can tell, Tim Sevener's calculations are correct as far as they go. He omits two major effects however. I. My eyes were not at sea-level. I was standing on a jetty. My head was 10 or 15 feet above seal level. II. According to a poster on talk.origins the atmosphere refracts light downwards. This effect means that light-rays bend down as they travel from Cuba towards Key West. The light can go around the hump, basically, which means that it is possible to see further than Tim's analysis suggests. Comments from Sci.misc people? These are the official opinions Mike Friedman of my organization. So, TOUGH!!
todd@uop.edu (Dr. Nethack) (02/28/88)
There is a similar phenomenon in California... If you stand on top of Mt. Diablo you can sometimes see Mt. Shasta. This is not supposed to be possible due to the curvature of the earth. But sometimes is possible, as temperature inversions (my assumption) cause the light to refract around the corner enough for a view. This has happened more than once.
ray@cs.rochester.edu (Ray Frank) (02/28/88)
Sometimes, when standing on the shore of Lake Ontario, you can see the city lights of Toronto across the lake which is over 60 miles away. I realize that this is only an atmospheric phenomenon and that I am really only seeing a mirror image of the Toronto. ray