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« on: March 29, 2007, 06:38:30 AM »
So here are the standard facts observable by anyone would find difficult to explain with a flat Earth hypothesis:
Pay attention now children,
(1) When ships put out to see, they sink below the horizon gradually.
First the hull goes down, then the masts, like so:
o
-+-
|
. / \ .
. .
. . /
. here you can still see the mast . |\ /
but the hull is below the horizon \ \/
\ \
This suggests that the Earth's surface curves away and downward from
wherever you stand. It's hard to observe this effect on land, because
mountains and trees and so forth get in the way when something moves
away from you before it dips below the horizon.
(2) If you climb higher, you can see further. On top of a mountain or
lighthouse, or in an airplane, you can see things that are invisible
-- below the horizon -- when you are on the ground. For example, if
you watch the Sun set, and at the very moment when the Sun is just
below the horizon you climb quickly up a hundred feet, you will see
the Sun again. It is hard to explain why you can see further when you
climb higher unless the Earth's surface curves downward away from you
wherever you stand.
(3) The Earth casts a shadow on the Moon during a lunar eclipse. The
shadow is round.
(4) When the Sun is directly overhead in any place, it is NOT directly
overhead at the same time in any place a few hundred miles away:
Sun's rays are parallel because the Sun is very far away.
| | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | |
V V V V V V V V V V V V V V V V
this stick ||
casts no ||
shadow || this stick
|| casts a shadow
. .
. . //
. . //.
. . //...
//....
. EARTH ....
...
If you were to put a stick in the ground sticking straight up at noon
in New York City, then telephone a friend in Chicago to ask him to
also put a stick in the ground sticking straight up, he would see a
shadow, and you would not. This is hard to explain unless ``straight
up'' (away from the Earth's surface) points in different directions
when you are at different places on the Earth's surface. That is, the
Earth is not flat.
(5) If you travel North, you can see stars at night which you never
saw before. Since there are so many stars, you only need to travel a
hundred miles or so. The new stars are stars that were hidden below
the horizon before you walked North. This couldnt be true if the
Earth were flat.
(6) There are tides in the oceans, which you can see at the shore,
that repeat every 24 hours or so. If the Earth were flat, then there
would be no tides, because the tides depend on their being a
substantial distance between the near and far sides of the Earth, from
the point of view of the Moon. This is kind of complicated, however.
Observation of the Earth from outside the planet shows it to be round,
nearly spherical.
if you look at the stars, the sun, and the moon, you do not see
any of them to be non-round. Since you observe them at different times and
from different angles, it seems plausible to say that they are round. Why
should the Earth be an exception?
Class dismissed.