# Stargazing About the wave nature theory In the case of Lunar Eclipse

1. Jul 12, 2010

### El-Korek

About the wave nature theory !! In the case of Lunar Eclipse

Hello all :)
First I'm glad to be a new member of this forum ..
Anyway .. as I noticed that if someone thought about a theory or a physics inquiry
you share your thoughts and solve the problem ..
So what came to my mind months ago some aspect related to optics ..
We studied that there are two theories about the nature of light :
- That it's made up of particles
- Made up of waves ..
the geometric theory and .. i donno the notation ..
anyway ..
so they found about the superposition of waves and explained the dark spots (fringe)
If there is a ball directing light towards it, it leave its shadow on the screen ..
BUT we would find a bright spot in the very middle of the screen
right ?
so i guess that verifies the wave nature of light

So my question lies here .. during lunar eclipse . when the sunlight is being blocked from earth by the moon
when the moon lies between the sun and Earth
the moon will leave its shadow on the earth causing the absence of light (eclipse) ..
So why isn't there the bright spot in the center of the screen of vision ( shadow of moon on earth ) ??
Any help ??

2. Jul 12, 2010

### Integral

Staff Emeritus
Re: About the wave nature theory !! In the case of Lunar Eclipse

The light from the sun is not coherent.

3. Jul 12, 2010

### El-Korek

Re: About the wave nature theory !! In the case of Lunar Eclipse

mmmmm
Well thank you !! I searched for the incoherency of the sun after your remark
and i found that :

As a consequence of this argument regarding point sources, one can show that a larger (or closer) thermal source of light produces light of smaller coherence area than a smaller (or more distant) thermal source of light. Sunlight therefore has low spatial coherence, while starlight has significantly higher spatial coherence.

Problem Solved !
Thanks to You ! :)
Cheers