Don’t walk under any ladders today. Here’s why we don’t like Friday the 13th. | VailDaily.com

Don’t walk under any ladders today. Here’s why we don’t like Friday the 13th.

Fear of the number 13 stems from Biblical stories.
Casey Russell | crussell@vaildaily.com

It might not officially be Halloween season yet, but this Friday is set to be a spooky one.

Yep, that’s right. It’s Friday the 13th, and to top off a day of superstitiously avoiding misfortune by tossing salt over your left shoulder and ensuring that no destructive items come near the bathroom mirror, at night, there’ll be a Harvest Moon.

What’s the deal with Friday the 13th anyway?

“Friday the 13th” might be a horror movie franchise, but it got its name for a reason. With cultures across the world converging on the number 12, 13 has always gotten a bad rap. There are 12 days of Christmas, 12 zodiac signs in both Western and Chinese astrology, 12 ancient Greek Olympians, 12 ancient Nordic gods, 12 temples of Israel and 12 months in the Gregorian and Islamic calendars.

There’s a word for fear of the number 13 – triskaidekaphobia – and some say that fear was born out of Biblical traditions. At the Last Supper, Jesus was joined by his 12 apostles, meaning there were 13 total guests present. Judas betrayed Jesus, Jesus was crucified on a Friday and superstitions around Fridays and the number 13 were born. Those superstitions flourished, especially in Christian Medieval Europe.

One of those superstitions was that when 13 sat down to dine, the first to rise from the table will be the first to die. Medieval Christians believed that if a group of 13 met for a gathering, one was a witch.

In the 19th century, one New Yorker wanted to prove there was nothing to fear, so he started a secret society. Captain William Fowler founded the Thirteen Club: it met every 13th day of the month in the Knickerbocker Cottage, a watering hole he owned. The guests dined in room 13 and defied other superstitions by walking under ladders before entering. Several U.S. presidents were part of the club, including Grover Cleveland, William McKinley and Theodore Roosevelt. There was another Thirteen Club in London as well.

Triskaidekaphobia survived into the modern age: hotels and skyscrapers rarely have a 13th floor, jumping from 12 to 14, and in fiction, apartments numbered 13B are either bad luck, haunted or some combination of the two.

What’s a harvest moon and why is it scary?

Harvest Moons are full moons that coincide with the autumnal equinox – sometimes they happen in October, sometimes in September. Around the autumn equinox, when day is the same length as night, the amount of time between the sun setting and the moon rising is at a minimum. On average throughout the year, there are 50 minutes between sunset and moonrise, but during Harvest Moons, that time is only 30 minutes.

And because the Earth’s orbit is not a perfect circle, some years, the moon looks larger than usual because of its changing position on the horizon. That’s why we picture giant orange orbs when we think of Harvest Moons. This year’s moon isn’t expected to look like a giant orange orb, because it’s actually a micro-moon this year: it will appear distant and small. Prime viewing time is at 12:33 a.m. on Sept. 14, but it still rises into the sky on the 13th.

While Harvest Moons in history gave farmers more light to harvest crops after sunset on busy days and were therefore seen as a good omen, full moons can also bring bad luck.

The moon has significance in many cultures, but one possible origin story for when the moon became a bad omen comes from the ancient Greeks and Romans. Known as Selene in Greek and Luna in Latin, the goddess of the moon was believed to have a negative effect on man and made people crazy. Both Aristotle the philosopher and Hippocrates the physician subscribed to this theory. Ever wonder where the words “loony,” “lunacy,” “lunatic” and “moony” come from? There’s your answer.

Of course, werewolves transfigure into their true form on the full moon, but besides harvest time, full moons were sometimes seen as good luck. Some believe that the best time to conceive a child is five days after a full moon. Having a full moon on a Sunday is unlucky, but it’s lucky on Monday. Some even believe the full moon can impact marriage, relationships and childbirth.

The next time a Harvest Moon and Friday the 13th will coincide is on Aug. 13, 2049. That alone might be reason enough to keep an eye out for strange happenings today.