How to Mentally Calculate the Day of the Week for Any Date
The so-called doomsday algorithm uses clever mental arithmetic and mnemonic tricks to enable a quick determination. Trick question: What day did September 6, 1752, fall on?
Every now and then a prominent religious zealot proclaims that the end is nigh. Harold Camping is the most recent example of such a doomsayer. He declared that judgment day commenced on May 21, 2011, and he also predicted that the destruction of the universe would follow on October 21. Wouldn’t it be nice to know which day of the week our universe would end? After all, if it were to fall on a Tuesday, why bother going to work that week?
It’s easy to declare that October 21 is a Friday, and many people can tell you that May 21 was a Saturday—because those are relatively recent dates. The real challenge is to determine the day of the week for an arbitrary date in history. One need not look very far for an arbitrary apocalyptic date.
In a book titled 1994?, Camping predicted that September 6, 1994, would be the end of days. Of course, that day came and went without incident. But what day of the week was it? While we’re at it, why don’t we raise the stakes further by rolling back the calendar a couple centuries: What day of the week was September 6, 1752, in England and its American colonies?