The setting of the sun is the prostration of the sun. That is a fact. The sun is mighty to mere humans. It too bows to the Lord of the Universe. The hadith helps us understand the blessing Allah swt has given us to keep track of time. The fantastic order of the universe as He devised its perfection. There is a place and time for everything, The sun is powerful. We depend on its heat and energy. Yet, this source of power sets.
The Prophet Ibrahim questioned this as well. Science comes from the Creator. He invented it.