Radiation, just as a review, is energy in transit, either as particles or electro-magnetic waves. Here's a quick look at the electro-magnetic spectrum from about 1 to about 280 nanometers UV-C. Now, probably some of the UV-C reached the early earth, but none of it reaches the Earth today. Parenthetically, almost all the UV work that's done in the lab, like for molecular or medical reasons and so on, is done using UVC with about 254 nanometer lamps. So the idea is that if you get a response to 254 nanometers, you're going to certainly get a good signal on whatever effect that you're looking for. But just to drive home the point, UVC does not reach the surface of the earth today. UV-B does, to a very small extent. This is what goes from about 280 to about 320 nanometers. I say about because I notice some of the Europeans use 315 nanometers. Very little of this reaches the surface of the earth, but it's got a much more energetic wavelength than UV-A, which is about 320 to 400 nanometers. A lot of this reaches the surface of the earth. This is not affected at all by the ozone shield but it's less dangerous than UV-C.

Just so we'll point out right now, before I forget to say this, the UV-B and UV-A aren't total disasters. You need UV-A for vitamin D production. Vitamin D deficiency in young animals causes rickets, osteomalacia in adults, and muscle cramps and twitching in everyone. UV-A is actually used to some extent to repair UV damage, which is kind of an irony that it's the same wavelength range that causes damage as well as repairing it. So UV is not just a total disaster here in terms of life. There are good parts. In fact, there are people that have been found in old age homes in particular, who have their curtains closed and so on, who suffer from these diseases caused by a vitamin D deficiency because they're not getting UV radiation and thus producing vitamin D. That's the origin of making children drink cod liver oil, because they weren't getting enough sun or vitamin D from other sources. Here's the visible range, 400 to 750 nanometers and then you go into the near infrared. So for UVwe're looking for wavelengths shorter than visible. But remember, UV-C doesn't reach the surface of the earth, a tiny bit of this does, and then more and more in the UVA and then there's quite a bit in the visible range because a certain air connection.

Narrative Index

Table of Contents

BioForum Index

AE Partners Collection Index

Activities Exchange Index