  Due to common misconceptions about the Church-Turing thesis, it has been
widely assumed that the Turing machine provides an upper bound on what is
computable. This is not so. The new field of hypercomputation studies models of
computation that can compute more than the Turing machine and addresses their
implications. In this report, I survey much of the work that has been done on
hypercomputation, explaining how such non-classical models fit into the
classical theory of computation and comparing their relative powers. I also
examine the physical requirements for such machines to be constructible and the
kinds of hypercomputation that may be possible within the universe. Finally, I
show how the possibility of hypercomputation weakens the impact of Godel's
Incompleteness Theorem and Chaitin's discovery of 'randomness' within
arithmetic.
