Did Xerxes invade Greece in 480 BCE because a phantom told him to do so?

A lot has been written on the Greco-Persian Wars. Was Herodotus' story that a phantom appeared to Xerxes at night true? Or did Xerxes have other, more tangible motives? Why would he take on the Greeks after his predecessor was so badly defeated by them. Perhaps the internal politics in the Persian court was a stronger motive than the appearance of a ghost. This source-based homework task is designed for students of the NSW Ancient History Syllabus for the Australian Curriculum
Higher School Certificate course
Historical Persiods: Option D: Persia - Cyrus II to the death of Darius III