irrational numbers

Well, as the title asks, are the physical constants of the universe (such as plank's constant or the gravitational constant) rational or irrational numbers? I sure can't see a ready fraction in any of them, but then again these numbers are determined experimentally, so how can you tell for sure...

Pi is an irrational number, meaning it never ends. It's infinitely long, therefore it must contain every possible combination of numbers an infinite amount of times. Does this mean pi contains every piece of software (in 0's and 1's) ever written? And if we could reduce genetic code to numbers...

Do mathematical entities really exist? Wowbagger's thread "Why is pi an irrational number" diverged at times into this topic. I found this former math professor's (@ University of Hawaii) essay on the subject ( http://www.math.hawaii.edu/~lee/exist.html ) pretty cool. It includes ramblings on...