Quote from : The Etymologicon: A Circular Stroll through the Hidden Connections of the English Language Book

If Jupiter was in the ascendant when you were born, you are of a jovial disposition; and if you're not jovial but miserable and saturnine that's a disaster, because a disaster is a dis-astro, or misplaced planet. Disaster is Latin for ill-starred. The fault, as Shakespeare put it, is not in our stars; but the language is.