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Just having a quick thought about light waves. Was reading a summary presentation on Einstein and the theory of Relativity and the fact that the speed of light is a constant when I was struck with the thought about light waves and space; A long time ago I remember doing an experiment on a wave machine that showed what happened when a wave hit an obstacle. When it hit the obstacle there was still water behind the obstacle but the wave carried on and eventually converged again a little further down the tank. This set me to thinking about light waves and was left wondering if the reason that the sky is black at night is because really we are looking up at a still patch in space. Where there should be light there isn’t because of the Earth’s mass. It is an obstacle to light waves from the sun. This would mean that the waves would then, following the physics of the wave machine, converge later on further into space. This then led me to think why cant we see that light? Is it just because that light is travelling away from our eyes? and therefore remains unseen and yet exists.

Due to our biology it is necessary for light waves to hit the back of our retinas for us to see and the reason we see objects is because light waves bounce off the objects and travel towards our eyes. So far all well and good. Looking up at the night sky you realise then that the light from the sun is travelling away from our eyes and therefore even though there is light we cannot see it. Then you realise that you only see the planets such as Venus etc because the light from our sun is reflecting off them. Also then due to direction the stars that we see we only see because their light is travelling in the right direction to hit our eyes. But from the wave machine we also know that when two opposing waves meet they cancel each other out. Could it be that the light from our sun is cancelled out by the light travelling from all the other stars? Is this another good reason why the sky is black at night?

Thinking about this makes you realise how limited we are. There is an awful lot that we just do not see. We really have a very small and polarized frame of vision. How different the world and our view would be if our eyes were different. This of course leads to thinking about other things that are unseen and yet exist! xP