http://abyss.uoregon.edu/~js/cosmo/lectures/lec08.html http://en.wikipedia.org/wiki/Quantum_mechanics http://en.wikipedia.org/wiki/Planck_constant http://dictionary.reference.com/browse/quanta http://en.wikipedia.org/wiki/Planck_constant So here we see reality is not continuous as it appears in the macroscopic world of Classical Physics, but it's true nature is discrete at the subatomic level as theorized by Max Planck and Neils Bohr.
Here is what the proponents of Digital Physics have to say: http://en.wikipedia.org/wiki/Digital_physics
Reality absolutely has to be discrete or else an electron would continue accelerating thereby losing energy and eventual falling into the nucleus, hence atoms could not exist.
Time. (And maybe space, which may or may not be continuous) No. Electromagnetism for example, is made up of photons which are quanta of light. While the strong force is made up of quarks.
any book on basic quantum mechanics. look for free electrons, free particles, positive energy particles,...