I was chargin mah lazer to counter your post, but then you countered it for me at the end.
Numbers are man made. If you ask someone, "What are numbers?" chances are they can't give you an answer. With numbers, it's easy to make things infinite. The graph of x squared goes off to infinity, but you could never draw out the complete graph because of that. Just the same way, 1 divided by 3 in decimal form would go on infinitely.
But since the question is about physical things, numbers don't count. I think time would be more likely to be applicable, but you run into the same problem of clearly defining it.