unlucky for some? Friday the 13th – also known as Black Friday – has long been considered an unlucky day.
where did the fear come from… and what is it all about?
Should we all be on guard?
As part of the Science Foundation Ireland Science Week, Dr. Richard J. Smith of the UCD School of Mathematics and Statistics compiled a list of thirteen fascinating facts about the number thirteen:
Paraskevidekatriaphobia is a fear of Friday the 13th.
2. Calendar Conversation
According to the Gregorian calendar, the 13th day of the month is more likely to be a Friday than any other day. In 2015, Friday the 13th occurs three times: February, March, and November. The next time this happens is in 2026.
3. Bad luck for some
Bad things happened that day – on Friday, October 13, 1307, the French king Philip IV ordered the arrest, torture and subsequent burning at the stake of hundreds of the military order of the Knights Templar. Several modern authors, such as Dan Brown in his novel The Da Vinci Code, have succumbed to the erroneous association of superstition with this grisly story!
4. Horse Tips
Taking ties into account, there are exactly 13 ways in which the top three horses in a horse race can finish.
5. Uncanny figures
The number 13 is considered a somewhat sinister number in several cultures, a bearer of bad omens compared to its much-vaunted neighbor 12 (the months of the year, signs of the zodiac, sons of Jacob, apostles of Jesus, and days of Christmas glory, to name a few). .
6. Number facts
13 is a prime number, meaning a number greater than one that can only be divided by itself and one. For example, six is not a prime number because it can be divided by two and three and by six and one. In fact, 13 belongs to the much more respected group of so-called Wilson primes, of which only three are known. If there is a fourth, it must be greater than 20 million million.
Prime numbers have fascinated mathematicians for millennia because they are the building blocks of all numbers, and nowadays they are used every second of every day around the world – whenever a credit card transaction is made online, prime numbers are used by computers to keep those details hidden from prying eyes.
7. Creepy creepy crawlies
Many species of the planthopper insect in the US have a life cycle of 13 or 17 years (another high point). Some believe these prime lifecycles help them avoid predators that periodically appear in their habitat.
8. Introduction to Fibonacci
13 is also a member of the famous Fibonacci sequence introduced in the 13th century. This sequence starts with zero and one, and the next number in the sequence is always the sum of the previous two, so we have 0+1=1,1+1=2, 1+2=3, 2+3= 5, 3+5=8 and so on. If you want to know why rabbits reproduce so quickly, look no further than the Fibonacci sequence.
Fibonacci is also responsible for introducing the decimal number system in Europe. Developed by Indian mathematicians centuries earlier and adopted by the Arabs, it revolutionized European banking and business because decimal numbers are much easier to calculate with than clunky Roman numerals.
9. Lucky for Some!
In certain countries, such as Belgium, some workers receive a 13th month paycheck. month”, so the number 13 can actually be quite a lucky number.
10. Horror Movies
There have been 12 movies in the Friday the 13th horror franchise. Maybe it’s bad luck there’s a 13th coming out in 2017?
Unfortunately, the origin of Friday the 13th superstition appears to be much more mundane – it doesn’t appear to be much older than a hundred years and may just be a combination of two things traditionally associated with bad luck, namely Friday and the number 13.
12. Hotel trivia
Fear of the number 13 means that hotels and hospitals often skip the 13th floor, and even airports sometimes silently skip gate 13.
Triskaidekaphobia is the fear of the number 13.
https://www.independent.ie/life/superstitious-13-things-you-might-not-know-about-friday-the-13th-34197054.html Superstitious? 13 things you might not know about Friday the 13th