Waverly Hills sanatorium where Dean and Sam collected the ghost souls is in Louisville Kentucky
Rowena's response, "So that was a gun in your pocket," when Dean draws out his gun and aims it at her is a humorous response to the infamous Mae West quote, "Is that a gun in your pocket, or are you just glad to see me?"
Out of all the season finales, season 11 has been rated the lowest.
The episode name refers to the first and last letters of the Greek alphabet, respectively, alpha and omega. The idiom "the alpha and omega" means something that encompasses the totality of its subject. It translates to the first and the last or the beginning and the end.
Brit twit astronomer discounts an overnight 6% reduction in solar output, mentioning the sun's periodic cycle. For perspective.. The 11 year solar cycle gives a total varience in output of 0.1% and it takes over 5 years to make that change. A permanent 6% drop approachs the trigger point for a global ice age.