Hello, first off, i'm not sure if i have placed this question under the correct forum, so i apologise for that. Secondly, i don't really know what quantum computing is, i'm basically guessing... To give you an idea of what my understanding of certain ideas might be, I start my undergraduate physics degree in about 2 weeks, so i am not exactly an expert. There is a kind of thought experiment that says we can never compute what the universe looks like, in it's entirety. By this i mean, we can't build a computer model of what every single electron, neutrino and photon etc is doing, going and how it behaves. (I think this is where quantum computing comes into it) The argument goes somewhat like this; Only "1 bit" of information can possibly be stored on a (fundamental?) particle. I think that the idea is the direction of spin, can count as either 0, or 1. Therefore if you had 50% of all the particles in the universe, you could encode the information about the other 50% on them. But since they have been used to hold this information, there is now not enough particles to hold information about the original 50%. (i hope this makes sense, or that you are already familiar with what i am attempting to explain). So my question is this; why can't the other half of the universe be used to encode information about the original half, that is already being used to record information about the second half... I have been trying to answer this myself, and the most likely explanation i can think of is that if you did that, you would end up with 2 copies of information that still only describes one half... If you can shine any light on this, that would be great. It's a puzzle that is really bugging me! Thanks, lntz.