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Thursday, January 18, 2007

If The Sun Is So Hot, Why Is It So Darn Cold?

If the Sun is producing so much energy and burning at 15 million degrees Kelvin, why is it so amazingly cold in the winter?

First myth debunked: The sun does not get hotter or colder. The sun stays the same temperature.

Second myth debunked: The Earth goes around the Sun in nearly a perfect circle. Yes, you’ve been told it’s an ellipse, which is an oval, but the Earth's orbit is barely elongated and very close to a circle. It isn’t cold because we’re nearer or farther from the sun during the year.

Besides, when it’s winter here in the U.S., it’s summer in the southern hemisphere. Australia is just as far from the sun as we are, but they’re at the beach.

So how can it be icy-cold winter up here in the Northern Hemisphere, but nice and toasty warm south of the equator?

The Earth’s axis, the imaginary line through the center of the Earth through the poles, is tilted. That’s why globes lay back on their sides some instead of spinning straight like a top.

To simulate this, hold a pencil in your right hand, make a fist around it (thumb up), now tilt it until the top of the pencil is pointing to ten o’clock.

That’s the way the Earth looks from space.

Rotate your wrist forward and back around the pencil, so that the pencil doesn’t wobble. That’s the Earth spinning.

Now, whatever you’re drinking is the sun. Assuming you’re holding the pencil in your right hand, put it on the left side of the cup. With your knuckles closest to the pitcher, er, cup, you can see that the sun will strike your pinkie knuckles directly. This is summer in Australia. The sun’s rays are close together and strike Australia dead on.

Now look at your first knuckle. Though it’s farther away from the beer, um, coffee, that’s not what we want to look at. Think about the Sun’s rays striking your knuckle. Your knuckle is slanted away from the sun, so the rays are more spread out. There’s more space between each ray. This is winter in the northern hemisphere, where the Sun’s rays are spread out, and the same amount of sunlight hits a bigger area of land, so it isn’t as strong.

Now put your hand on the right side of the pitcher and look at summer in up here and winter in the Down Under. The top of the pencil should be pointing toward the Corona . . . or latte.

To feel the effect of spread-out rays, try this with a light bulb: feel the heat with your hand flat in front of it, then slant your hand back and feel that it is cooler when the same amount of light spills over more of your hand.

Don’t you wish you were in Australia, catching some rays?

TK Kenyon

For more literary pursuits, try TK Kenyon's column Recommended Reading at Suite

For very literary pursuits, try reading the first chapter of RABID: TK Kenyon's blockbuster novel coming in April, 2007. Read starred reviews of RABID here.

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