Time vs. Energy

I just had another thought in regard to my previous post. If you could accelerate mass to the speed of light, would it become energy? If time is stopped for something, what is it, then? It is never-changing. Static. Isn't energy like that? You can convert energy from one form to another, but it is never lost.

What *is* energy? What is matter, for that matter? I guess these are the questions that keep physicists busy their whole lives. Me? I just want to go eat something.