Why are they all praying? The Errant-Event Syndrome.
The book's title reflects the question a little boy asks his mother in the midst of the chaos and terror caused by the failure of nature’s critically important Principle of Causality as a group of sciewntist strive to correct the problem. Hold up an apple, then let it go --- if it didn't drop, you have experienced an Errant Event and belong in the story! Physically, it could happen.