Why does light bounce of objects?

Question

canislupus · Answer

Oops. Don't know how to 'edit'. Should be 'Why does light bounce oFF objects?

kyanthedoodle · Answer

http://www.ivyroses.com/HumanBody/Eye/Light-on-objects.php

anonymous · Answer

just try to do research on reflection of light

canislupus · Answer

Mizam, that is not exactly the focus of my question. I am wondering how the 'bouncing off' works. What does a photon 'bounce off' from? Richard Feinman mentioned the dynamic in QED, but even he couldn't explain it. I was wondering if anyone in here knew.

aaronq · Answer

if Feynman couldn't explain something i'm afraid none of us will be able to lol

I mean you could look at the opposite process, when does light NOT bounce of objects?

>when it is absorbed, right?

why does light bounce of objects?

>because it's not absorbed

So that's the short answer.

rvc · Answer

awesome @aaronq

anonymous · Answer

Yes sadly Feynman was famous for admitting that no one really understands this stuff.  However, roughly speaking light "bounces" off of things because most things in the universe have some probability to reflect light and some probability to transmit it.  Of course, light can be absorbed, but, again roughly speaking, that is the same as transmission (past the surface layer).  
Light "bouncing" off of objects can most easily be understand as light waves reflecting.  As an electromagnetic wave, it is a true embodiment of a fluctuating electromagnetic field.  This field interacts with the fields surrounding the atomic structure of the object (for instance the electrons of the atoms) which causes them to respond inducing further fluctuations.  Now this is quite a complicated matter even though I am making a bunch of severe simplifications, but thankfully there are tools and techniques that exist for us to su up the infinite amount of possible ways these fields and particles dance together to give us those two useful numbers I mentioned earlier, the reflection and transmission coefficients.  Using these it is possible to tell, how much light a given object will reflect or transmit; however it is truly impossible to say why a given photon wants to "bounce" off the object or be absorbed, or if that is even an appropriate way of thinking about how they interact.