Is the Australian currency different from the US currency?

Yes, both curencies are substantially different from each other in both value and appearance. Australia uses the Australian Dollar (AUD) and the USA uses the US Dollar (USD). Both currencies have 100 cents to the Dollar and they are both traded on the world market. One Australian Dollar almost never equals one US Dollar, their respective values change on a minute by minute basis with respect to each other and with respect to other currencies.