How many universes are there?

[wstein]

I'm sorry but being not a very smart person myself, knowing next to nothing about what is described here and English being my second language....this is kind of impossible to understand...can you explain this in a dumb person friendly way please?

Can't dumb it all the way down. Truthfully, no one alive today understands Quantum mechanics in full. In fact, though its put forth like its a theory, it actually a description based on observations. It works well in predicting outcomes but does not explain what is happening. Some of the smartest people in the world are using the biggest equipment ever built, and they still haven't figured it out. SO, don't feel like this reflects badly on your 'smarts'.

I will try to explain the basics. In the classical world (the one you know) things have a definite parameters (in terms of frequency, position, energy, momentum, etc). When things meet, some singular result happens (though you may not know what that is).

In the quantum world the everything is probabilistic. First particles (includes light) are actually a spread of possibilities (in terms of frequency, position, energy, momentum, etc). The possibilities are similar to the conventional ones you expect however, its all of them not a particular one. When these spreads of possibilities called particles meet, the result a new spread of possibilities.

So a more tangible analogy. The classical way of looking at things is like tossing two balls at each other. They either pass near each other continuing on their way or they collide and bounce of at an angle. There is a clear outcome to this event. The quantum view is more like throwing two buckets of water at each other. Water goes all over the place, some continues on, some bounces of at angles. If the original trajectories of the water are more or less a head on collision, more of the water will bounce off at angles. If the water is not well aimed, more of it will continue along its original trajectories. Some always passes by and some always bounces off. This happens regardless of the original trajectory of the water, even if the water tossed in opposite directions away from each other. Based on the original vector of each bucket of water, quantum mechanics can very accurately predict how much will pass through and how much will bounce in various directions.

The more accepted interpretation is that in the quantum view, 'things' are actually more like waves than particles. They bounce, refract, and pass through each other all the time, no big deal. Think ripples on the surface of a lake. The up and coming interpretation is that particles are real things but there is not one copy of everything, there are lots in parallel worlds. In each world 'that' particle is in a slightly different situation. When two particles meet, there are actually a vast number of very similar particles all meeting in nearly (not not exactly) the same way. As each is slightly different, the outcomes are slightly different. So in sense, 'that' particle meets another in all possible ways. The multiworlds interpretation is that actually each particle meets in a singular specific way but it has many twins that simultaneously meet in slightly different ways.

Its all counter intuitive. Either way, quantum mechanics suggest something that defies experience. Did one thing do multiple things at once or are there vast quantities of parallel worlds doing almost but not exactly the same thing at each instant?

Don't know if you are more or less confused at this point. Perhaps this will all be cleared up when the theory is complete. Right now all we have is a bunch of experiments that clearly show something really odd is happening at the smallest scale. Quantum mechanics is one explanation and possibly not the right one. All we know for sure is that its equations have allowed us to build all sorts of high tech devices (includes computers).