Large blue light seen sweeping over Townsville in fast, erratic movements.Large bright blue light sighted from a balcony facing the radio towers in Townsville, passing from south to north. The light performed a sweeping loop near Castle Hill, before travelling quite fast in a northerly direction. It would be erratic and perform huge dips. It was almost as bright as Venus and was flashing blue. It would occasionally go behind low lying clouds. It made no sound.It was in view for about 3 minutes before dipping towards the horizon and behind the ground lights. It almost looked as if it was travelling on the winds and falling through air pockets, but it was far too big to be so susceptible to that.