Some Christians believe Friday is unlucky because it’s the day Jesus was crucified, and 13 signifies the number of guests at the Last Supper, with the infamous Judas being the 13th person seated at the table. The answer is unclear but our aversion may have religious origins. Lisbett Lindstad/CNN iReportĪ glowing (but mini) harvest moon will light up Friday the 13th Lisbett Lindstad took this photo of the harvest moon early Saturday morning in Vikersund, Norway.