Friday the 13th and a full moon can lead to real fears for some

If you’re a selenophobic— people who fear the moon— or suffer from friggatriskaidekaphobia—fear of Friday the 13th— you may not want to leave the house today.

For the first time in nearly a century, there will be a full moon rising on Friday the 13th. And for some, superstitions of these two phenomena are very real.

“In the U.S. there are millions and millions of people who just want to stay home and not take any chances on either one of these – Friday the 13th or a full moon – and here they are both together,” said Mike McKee, a psychologist at the Cleveland Clinic in Ohio.

Fear of Friday the 13th goes all the way back to medieval times, when it seemed like a lot of bad things — hangings and executions — occurred on Fridays, McKee said. The fear of the number 13 may derive from the 13 people who attended the last supper of Jesus.

The words “lunatic” and “lunacy” come from the word “lunar,” the Latin word for moon. The June moon is also called the “Honey Moon” because of its color and the high number of weddings held this month.

Some believe a full moon’s gravitational pull may also influence people’s behavior.

“There are some people who really believe that it pulls water in the body the way it does tides in the ocean and that that somehow makes people behave oddly, or makes them more prone to accidents,” McKee said.

However, many scientists have noted that the moon’s gravitational pool on the body is so exceptionally minor, you can’t even notice it.  Additionally, there are tons of other gravitational forces – most notably from the Earth – that have a much stronger, more obvious effect on our bodies than the moon’s pull.

Still, combining a full moon and Friday the 13th may be stressful for some, so if you are feeling anxious about today, your best bet is to attack it head-on.

“All of these superstitions only have the power that you give them,” McKee said. “Otherwise, they are absolutely zero.”

The next time a full moon rises on Friday the 13th will be in the year 2049.