In certain nations, the number 13 is considered unlucky. The conclusion of the Mayan calendar's 13th Baktun was feared as a foreshadowing of the cataclysmic 2012 phenomena. Fear of the number 13 has its own phobia, triskaidekaphobia, which was created in 1911.
The term "bad luck number" refers to any number associated with danger, death, or destruction. Although 13 is often cited as a bad luck number, it can be any single digit that increases the risk of something bad happening to you. Examples include 4 for death, 7 for illness, and 9 for accident. The only positive number associated with death is 6, because it means you will survive sine die (without dying).
There are several theories about why some numbers are considered bad luck while others aren't. One theory is that numbers contain energy at specific frequencies, and when these energies are combined they can cause problems if not balanced properly. For example, if you add up all the digits of a phone number, it will be an even number. If it's divisible by two, then it's safe to call someone back on that number; if it's not divisible by two, then there's a chance they won't pick up the phone. Another theory is that certain numbers are more powerful than others, and so should never be used in manufacturing equipment or applied to the face.
Everyone knows that Friday the 13th is a bad luck day. Jesus was killed on a Friday, and the day has since been connected with "general evil omens," according to Michael Bailey, a history professor at Iowa State University who specializes in the origins of superstitions.
In China, India, and Japan, it is believed that people should not kill any animals on this day because it will cause trouble for them. In Japan, it is recommended that people do not walk under a ladder or touch its legs. It is said that if you do so, you will bring bad luck to your family.
In Europe, South America, and North America, Thursday the 12th is also considered bad luck. This is because Thursdays are often associated with violence and tragedy: the assassination of President Lincoln, the World Trade Center attacks, and the Oklahoma City bombing have all occurred on Thursday. The idea behind avoiding tragedy on "bad luck" days is similar to that of doing something to prevent accidents, such as wearing a helmet when riding a motorcycle or using safety nets while climbing a ladder.
The connection between Thursday and bad luck began after the Norman conquest of England when French customs took hold in the country. During this time, it was common practice for soldiers to kill animals on Fridays in order to keep evil spirits away from them on battle days.
On Tuesday, the 13th, I'll be gone. Tuesday the 13th is considered highly unlucky in Spain according to a Spanish tradition. Apparently, their "Tuesday the 13th" correlates to our "Friday the 13th," and you should avoid getting married or traveling on that day. 14. Wishing a buddy "happy birthday" before their real birthday is considered bad luck in Germany. 15. In France, it's bad luck to wear red underwear on Thursday the 30th of each month.
In England, it's believed that if you see the moon on Tuesday the 13th, then something bad will happen to someone near you. The reason for this belief is that on January 13th, 1572, the Moon was completely covered by a total lunar eclipse. It was because of this event that Shakespeare used this phrase when talking about the death of Macbeth: "Out, damned spot! Out, I say!" (Macbeth vii, 7).
In Japan, it's considered bad luck to return home after midnight.
In Italy, it's not recommended to watch fireworks on Tuesday the 13th because it will bring misfortune to an unborn child.
In South Africa, it's believed that if you walk around with a red handkerchief in your back pocket on Tuesday the 13th, then you're going to meet your fate soon.
Thirteenth As a result, because the number 13 is considered bad, it is never used as a home number or a number in a storey structure. Opening an umbrella inside the house is considered unlucky. If it is closed, then someone close to the owner will not live long.
Twelfth The same thing happens here: opening a door with twelve and closing it is also considered unlucky.
Eleventh In the United States, Canada, and the Caribbean, the number eleven is considered bad luck. An eleventh hour visit from a friend or family member is missed because they are too late; an invitation for lunch or dinner is cancelled at the last minute. If you knock on a door at eleven o'clock, you will usually be told that nobody is home.
Tenth A similar story in the United Kingdom, Australia, and New Zealand: if you dial ten digits in America, only nine digits in Britain. If you leave out one digit when calling the police, you will be sent to the wrong number.
Nineth It is believed that if you see nine angels dancing, it means that your loved one will return home soon.
Eighth It is said that if you see eight balls into two pairs, it means good news will follow. If not, then it's bad news.
Why is the number '7' considered to be the most auspicious? The answer may surprise you: it's not 3 or 11, as many would assume; instead, it's 7. Here's why: all major religions have a special meaning associated with this number. Christians believe that Jesus was crucified on a Friday, which added up to Thursday plus Saturday equals Sunday, so they call March 31st "Good Friday" and April 1st "Easter Sunday". Jews celebrate Easter (or Paskha) on the first day of the month of Abib, which falls between April 11th and May 11th. Muslims celebrate Ramadan during the ninth month of the Islamic calendar, which begins when the sun enters Aries at sunset on April 20th and ends with the full moon after midnight on May 20th.
Number theorists have used their skills to create what are called "perfect numbers". These are integers that are equal to the sum of their proper divisors (factors). The only perfect numbers below 1000 are 6 = 2 × 3 and 28 = 7 × 7. Beyond this point, there are many more perfect numbers. The largest known example is π⁴ ≈ 1.246 * 10^238.