This is scientific Americans 60 second science. I'm Karen Hopkins. This will just take a minute.

It's Friday the 13th.

You could ask yourself a questioniskay Decophobia.

That's a fear of the number 13.

Napoleon, Herbert Hoover, and FDR are well documented Triskidecophobics.

But why do folks think 13 is unlucky, particularly when it falls on a Friday, as it will

three times this year?

The University of Delaware's Thomas Fernsler is known as Dr. 13.

He's an expert on the number's bad reputation, which may date back to biblical times.

After all, the 13th guest at the Last Supper was Judas, and you know how that worked out for Jesus who was crucified on a Friday.

Other factoids from Fernsler, the first person to die in a car accident was killed in New York City

on September the 13th in 1899, although that was a Wednesday.

And the ill-fated flight of Apollo the 13th launched at the 13th minute of the 13th hour,

Central Standard time, on April 11th, 1970.

Can the numerals in the date for 1170 add up to Gasp 13, as long as you don't include the 19 in

1970?

Hey, sometimes superstition can be hard work.

Today, some tall buildings lack a 13th floor.

Well, they have a 13th floor, but they call it the 14th floor.

Because the purveyors of bad luck are apparently easily fooled.

Meanwhile, over in France, panicky Parisian party throwers can even hire a Kedtseum, a professional 14th guest.

Like Judas, Mark Twain was allegedly once poised to be the 13th guest at a dinner party.

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