After death

The only possibility of "rebirth" is that the universe will one day be pulled together again by dark matter / dark energy and during another "big bang" some of your atoms / energy will end up on a planet that can sustain life, and those atoms / energy become part of a living organism once again... Since this (in theory) can happen infinite times, you will become alive one day... but saying that, it's also possible that we have been alive already, some infinite times ago! .

That doesn't really even mean anything though. The atoms in your body aren't you:

http://www.scienceofidentityfoundation.o...page=0%2C1

Recent studies at the Oak Ridge Atomic Research Center have revealed that about 98 percent of all the atoms in a human body are replaced every year. You get a new suit of skin every month and a new liver every six weeks. The lining of your stomach lasts only five days before it’s replaced. Even your bones are not the solid, stable, concrete-like things you might have thought them to be: They are undergoing constant change. The bones you have today are different from the bones you had a year ago. Experts in this area of research have concluded that there is a complete, 100 percent turnover of atoms in the body at least every five years. In other words, not one single atom present in your body today was there five years ago.

So even if this were to happen, it wouldn't really mean anything.