Re: Planets and Stars - an idea

"Terence Nesbit" <TerryKidd@xxxxxxx> wrote:


"Wayne Throop" <throopw@xxxxxxxxx> wrote

The sun shins on exactly half the planet, all the time.
This is required by the simple fact that the earth is a sphere
(more or less), and the sun is far, far away and can be treated
as a point source at a great distance, to a first approximation.

And this is completely and utterly compatible with a 16 hour
day, and it's easy to depict. Trivially easy.

Not even this makes sense to you, does it?

A 12 hour day along a given latitude requires 12 hours of daylight along
that latitude. A 16 hour day requires 16 hours of daylight along that
latitude. Whether the Sun actually shines for that long does not matter.
But at no point can a 16 hour period be depicted by seeing only one half of
the sphere unless it is balanced by an equal distance on the unseen half of
the planet. That half will show just as much sunlight as the visible half
does were that side looked at instead.

No. If there is 16 hours of sunlight (16/24 of the lattitude line is
exposed to the sun), then there is a matching lattitude line where
there is 16 hours of DARKNESS (16/24 of the line is dark). In your
paragraph, "unseen" means you are looking from the sun's position. So
that half will show just as much NIGHT as the visible half shows
daylight.


This is all that I was saying, and it has not been depicted properly.
Viewed from one side, where both shadow and sunlight can be seen, it appears
to look like that Earth is 2/3 to 3/4 covered in Sunlight.

Viewed from the north pole as we approach June, it looks like 2/3 to
3/4 of the earth is covered in sunlight, sure. So long as you
remember that from the other pole it's 2/3 to 2/4 darkness.
--
Tomorrow is today already.
Greg Goss, 1989-01-27
.

Relevant Pages

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  • Re: Planets and Stars - an idea
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