I thought there were virtual particles popping into and out of a existence...my thought process was that if we could know how many pop into/out of in a cubic meter of space you could multiply that times the volume of the universe and then get an interesting fact...e.g. the size of a baseball/every second ... or am I completely wrong in my understanding? from wiki, it seems that virtual particles do exist and act like real particles the longer they exist. I don't know.