All this talk of the LHC has me thinking. I know matter is made of various subatomic particles, but then what are those particles (leptons, quarks) made of? Is matter simply a form of energy? I know this is very reductionist thought, but it seems odd to me that fundamental units of matter would stop at leptons, quarks, and the other particles. Also, I know that matter can be converted to energy (nuclear fission for example.) But is the reverse true? Can energy be converted into matter? Are there any examples of this happening? Combining the two questions, if matter and energy can be converted from one to the other, wouldn't this at least imply that perhaps one is made of the other? I've done a little light research into this on the web but it popped into my head on my way back from class and it'll bug me for the rest of the day :P If there's a previous post on this, I'm sorry for the double post, I didn't see anything in the search. And feel free to link me to other answers/sites, or explain it here. Thanks in advance.