The Initial Singularity
 When the Universe was very young, the distances between
things were very tiny.
 Quantum mechanics is needed to describe very tiny distances.
 For instance Heisenberg's uncertainty relation should apply here.
 The equations describing cosmology come out of the theory
of general relativity which does not include quantum mechanics.
 The equations of general relativity are only valid when
describing distances larger than 10^{35}m.
 Or equivalently, general relativity only describes the
universe when it is older than 10^{44} s.
 In order to describe the earliest times, a theory which
combines gravity and quantum mechanics is needed (called quantum gravity).
 One theory which might work is called Superstring Theory.
 Superstring theory predicts that the universe is actually
10 dimensional, but that we only directly experience 3 dimensions.
 Superstring theory may be able to describe the earliest times
properly.
 This is still unknown territory!

