yes I could :)
but what research have you done for yourself so far ?
have you even tried to type your topic title into google ?
the first google hit was a wiki link that told you everything you would probably want to know
on Physics Forum, we try to encourage people to learn to do research, rather than have some one just spout out all the answers. You will learn much more that way :)
If there is something specific in that wiki link you don't understand, then ask specific questions
regards
Dave