Monday, January 09, 2006

Knowledge Tidbit

I love learning stuff. Someday, I’ll learn how to write well, but that’s for another day. Today is Myth Dispelling Day. While searching for a song, I stumbled upon a site at Penn State that debunks weather myths. So cool.

Here’s my myth of the day:

The greenhouse effect is caused by gases and radiation (heat) bouncing off the earth’s atmosphere.


Maybe I’m the only dumb one, but I’ve always believed that statement without question.

Silly me.

The earth’s atmosphere does NOT act as a blanket. A blanket prevents heat from escaping (convection). The atmosphere actually facilitates convection rather than prevents it, as incorrectly implied by the term greenhouse effect.

The surface of the earth receives heat from two sources – the Sun and the atmosphere. In the absence of an atmosphere, the surface of the earth would be almost 50 degrees cooler. Imagine the summer temperature being below freezing. That would put a damper on a nice day at the beach. So, the greenhouse effect is actually a good thing.

Both the Sun and the atmosphere have finite temperatures, i.e. they are not getting hotter or colder. However, the atmosphere does absorb radiation from the earth. What is commonly misunderstood is that upon absorption, this radiation no longer exists. Because it has a finite temperature, the atmosphere then emits radiation of an entirely different spectrum back to the earth, in accordance with the Laws of Thermodynamics.

Thus, all the pictures showing heat rising from the earth and bouncing off the atmosphere are completely wrong.

How’s that for a golden nugget of knowledge!

I know.

I’m a total geek.