The premise is incorrect. The sun does not "travel north" in Australia or anywhere else. Its apparent daily motion is east-to-west due to Earth's rotation. Seasonal changes in the sun's path (higher/lower in the sky, rising/setting positions shifting north/south) result from Earth's axial tilt and orbit—not the sun moving. In Australia (Southern Hemisphere), the sun is generally to the north at solar noon, but it doesn't "travel north" as a distinct phenomenon.