The AUD/USD news can be seriously affected by the decisions taken by this organizations and people: Reserve Bank of Australia (RBA) that issues statements and decides on the interest rates of the country.
However, the most important defense is the dissertation defense which comes at the end of a long and arduous process and which may have unfolded over a number of years. The dissertation defense is a significant milestone signaling closure on your graduate student career.
1 A thesis is a hypothesis or conjecture.  A PhD dissertation is a lengthy, formal document that argues in defense of a particular thesis. (So many people use the term ``thesis'' to refer to the document that a current dictionary now includes it as the third meaning of ``thesis'').