Posted 07 October 2013 - 10:18 AM
Posted 07 October 2013 - 11:15 AM
Posted 07 October 2013 - 11:50 AM
Posted 07 October 2013 - 02:47 PM
Posted 07 October 2013 - 03:52 PM
Posted 07 October 2013 - 05:40 PM
Note that some animals have evolved the ability to see in infra-red (pit vipers) and ultra-violet (many insects). So there is nothing magic about the human visible spectrum - we could have evolved sensitivity to wavevlengths slightly above or below what we have. It's get harder to go extremely far out of our range due to chemistry - you have to have a chemical receptor that will capture photons of the wavelengths we see. Extremely long waves (radio or lower) don't have enough energy to change a chemical bond, and extremely short waves (x-ray and higher) have so much that they tend to destroy the chemical when they are absorbed, or just pass right through.