Friday, December 21, 2007

Winter Solstice--Nerd Style



The earth's axis is pointing away from the sun.

The sun's angle of insolation or where the sun's rays hit the earth is approximately at the Tropic of Capricorn, the furthest tropic line from the northern hemisphere.

Incidentally, the word insolation comes from parts of three different words: in-coming solar radation. Cool, huh?

So you can see that if the angle of the sun's rays are skewed to the south of the equator that we would not have an equal day, but a shorter one or of course my favorite way of putting it: a longer night. Of course when the sun's angle of insolation is at the equator then we get an equal day and equal night, but we're not in the season of either equinox so I won't go into it at this time.

The reason for the season is not actually for giving as they say in a consumer based nation, but because of the tilt of the earth's axis, which is 23. 44 or so degrees. I always found it interesting that both tropics, each on the 23.5 lateral of opposite sides of the equator, and the tilt of the axis were very similar in numbers. It makes sense, but I do wonder if the exact or approximate degree of the tilt of our axis was found after noting the sun's angle of insolation to the tropics. I'm sure smarter people probably wouldn't ask that question because it would be too obvious or even easy to find the answer in an encyclopedia or the internet for that matter, but I like to put those questions out there before checking my sources, because without the question then it's all answers and what fun is that?

Ironically the earth is closest (perihelion) to the sun during our winter, more specifically, I've read it to be the closest around Jan 3rd. It is also true that our winter is warmer than that of the southern hemisphere. It has to do with the Antarctic and the placement of continents and I suppose that the earth's proximity to the sun plays a factor in that too, but I haven't read that yet. I believe the that the placement of continents play a role, because water has a higher heat capacity than soil and rock (continents)........

Enough said! From Nerdville--enjoy the winter solstice!

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