Hello all:
I can not believe how many of you wrote back to answer my questions. Thank
you all so much! I think it was Roger who thanked me for asking a good
question. That must mean that he agrees with the theory that there are no
dumb questions, just dumb people who ask them!
If I had only taken the time to make a quick and simple drawing of the
earth and these longitudinal parallels, it would have disproved my theory of
direct proportions and given me close approximations of the answers I
needed. I learned a good lesson:
When in doubt, make a drawing!
(or ask you guys)
I came up with my flawed and doomed formula while flying back to Tucson from
holiday in Bermuda last week. Lacking a good book or a pencil and paper, the
only thing I had to look at for three hours, was the window and the bald
head of the man in front of me. I chose the window. Outside, the only
things visible were the deep blue sky, the thick white cloud layer below,
and the wing.
It was a late afternoon flight and the poor pilot was flying straight into
the sun. I couldn't see the sun directly from my window, so I couldn't
determine its altitude above the horizon directly. However, there was a
series of little fin-like things attached to the top of the wing. They were
about an inch tall and triangular, looking a bit like little gnomons, so I
used them as solar altitude indicators. As the sun was low when we started,
they cast about six inch shadows, but after three hours of flying, the
shadows had only grown to about eight inches. The sun just didn't want to set.
I wondered how fast the plane must travel to keep up with the sun. Well, if
we were at the equator, that was easy: circumference/24 hrs.=velocity. This
would be 40,053km./24hr.=1669kph or about 1000 miles per hour. But for
higher latitudes, realized that the plane could go slower to keep up with
the sun. Knowing that the average jet airplane flys at about 500 mph (800
kph), I wondered at what latitude it would have to be at, traveling west, to
exactly keep up with the setting sun.
Thanks to your answers and my little drawing, I now know the answer. But I
won't say what the answer is, I'll just leave it as a fun puzzle for someone.
Thank goodness for wing gnomons and dialists!
John Carmichael
http://www.azstarnet.com/~pappas
