Karma

Karma is centuries old concept that has to do with consequences of one's actions. In order to understand it we have to make few assumptions. First of all we have accept the existence of human energy field. For references of scentific validation of human energy field existence please refer to Barbara Brenan "Hands Of Light" and "Entangled Minds" by Dean Radin. By the way Radin's book was recommended by two nobel prize winners which really adds to its credibility.
We also need to dvelve into quantum physics a little bit. There is an interesting concept in quantum physics called "quantum entanglement" (http://en.wikipedia.org/wiki/Quantum_entanglement) In simple words the idea is that two tiny particles of matter separated by any distance continue to influence each other. The implications of this are very far reaching. What it basically means that everything is interconnected and interellated in the universe. Distance is irrelevant. It is actually another illusion. On astral plane the distance as such doesn't exist, your though will move you anywhere instantly.

Your every thought or action influences everything else and everybody else in the entire universe. What we call matter is nothing more than condensed energy. The famous Einstein equasion affirms it: E=MC2. Human energy field consists of multiple layers of energy/information. One of the famous physicists that spend his entire life studing elementary particles on his Nobel prize award ceremony said that after many years of research he concluded that there is no matter.

Suppose you do something bad to your fellow human. His/her response is intense negative emotion directed at you. That negative energy will distort your energy field and encode some future negative event in it. Pretty much like a software program would write something on the hard disk. In other words when you are wishing somebody bad, you actually creating this person negative future. This is pretty much what karma is. It works both ways the negative and the positive.

Your karma can span multiple lives. Not necessarily you would be paying for all the nad you've done in this life it can be pushed to one of your future lives. What is also important to remember is that if you wish for something to happen and it is impossible in your present life it may be programmed to occur in your future life. For example you would like to be a musican while you are a carpenter in this life. There is high probability then that you will be a musician in one of future incarnations.