Superstitions and emergencies in the city.
Facts and myths about Fridays, Good Fridays,
the number 13 and the phases of the moon
in the Swiss capital
A. K. Exadaktylos MD, G. Sclabas, S. Eggli MD, J. Luterbacher PhD*,
H. Zimmermann MD
Dept. of Trauma and Emergency Medicine, Inselspital,
University Hospital of Bern, Switzerland
*Dept. of Climatology and Meteorology, Institute of Geography,
University of Bern, Switzerland
Keywords: Friday the 13th, full moon, new moon, superstition, trauma, emergencies
Correspondence to:
Dr. Aristomenis K. Exadaktylos M.D.
Notfallzentrum-Emergency Medicine
University Hospital Bern
Inselspital
3010 Bern
Switzerland
e-mail: exaris@hotmail.com
Phone: +41 31 632 2442
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Abstract
Purpose—To examine the superstitious believes of having an increased risk for accident on
the rare occasion of Full moon, Friday 13th of October 2000 and Good Friday, 13th of April,
2001, compared to full moon days and nights between January 2000 and April 2001 and
compared to any day without a full moon. Historic and scientific review of superstition.
Design—Retrospective analysis of Emergency Unit data using new ER software.
Subjects—Minor and moderate trauma, multiply injured patients
Results—Compared to the previous eight full moon shifts of the year 2000 and 2001, we
noticed no significant increase in trauma- emergencies. Fewer trauma patients were seen on
Friday the 13th in October 2000 compared to other full moon days and nights. On Good
Friday 13th 2001 the number of admitted patients was slightly but not significantly increased.
Conclusion— It seems that full moons, Friday the 13th and a full moon and Good Friday the
13th in defiance of all superstitious beliefs, are not associated with a higher risk for injury.
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Introduction
What is a superstition? It is defined as a "belief in, or fear of, what is unknown, mysterious, or
supernatural; religion, opinion, or practice based on belief in divination, magic, omens, etc."
Superstitions have been with mankind since the beginning and will undoubtedly remain until
the end. Superstitions are woven into every culture and cover almost everything that one
might think of. One of the oldest superstitions links Friday, the number 13 and the full moon.
There exists a very popular belief in a relationship between the number 13 and Friday as well
as the moon’s phase and the incidence of bad luck . One of the most influential writer of
Renaissance esoterica has been Heinrich Cornelius Agrippa (1486-1535) . His “de occulta
philosophia” appeared in three books. Written from 1509 to 1510, it circulated widely in
manuscript form, and was eventually printed in 1533. It is a "systematic exposition of ...
Ficinian spiritual magic and Trithemian demonic magic (and) ... treatised in practical magic"
In our times various scientific studies examined the correlation between the moon’s phase and
major trauma or the relation between Friday 13th , health and behaviour of people 1,2,3,4,5
The very rare occasion of Friday 13th and full moon in the year 2000 inspired us to
investigated the amount of emergencies on such superstitious over an eight month period. But
we could not proof any significant change in medical emergencies 1. This year another very
rare constellation of the calendar attracted our interest, Good Friday the 13th of April, as rare
as the previous Friday 13th and a mysterious date for Christians all over the world.
The purpose of this new study was to examine exclusively the risk of having an accident on
a Friday 13th in comparison to a full moon day and in comparison to an average day over a
fourteen month investigation period . An other aim of this publication should be to explain in
greater detail the religious and scientific background of these superstitions.
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Scientific background
Full moons are defined as three-day periods in the 29,531-day lunar cycle, with the middle
day being described as the full moon in the World Almanac2. Every year has at least one
Friday the 13th, but as many as three can occur in a 12-month period. Over the last 100 years
(1901 to 2000) this combination occurred 171 times. Occasionally the full moon phase
coincides with a Friday, and very rarely with the 13th day of a month. During the 20th century
this constellation arose nine times: March 1903, October 1905, June 1919, January 1922,
November 1970, July 1984, February 1987, March 1998 and October 2000.
The next combinations of a full moon and Friday the 13th will be in June 2014 and August
2049. Together with the Earth’s force of gravitational attraction, the gravitational forces of the
moon and sun also act externally upon the Earth’s ocean waters. These external forces are
exerted as tide-producing, or as the so-called “tractive” forces. Their effects are superimposed
upon the Earth’s gravitational force and act to draw the ocean waters to positions on the
Earth’s surface directly beneath these respective celestial bodies. The moon, being much
closer to the Earth than the sun, is not only the greatest influence on our tides, but its phases
also greatly affect their character. The tide-raising force of the sun is only about half of that of
the moon. As the moon orbits the Earth, it aligns with the Earth and sun semi-monthly, during
the full moon and new moon phases. At such times, we have extremely high and low tides
(spring tides).In various cultures, the combination of Friday the 13th and a full moon is
thought to bring bad luck or “bad weather” connected with natural disasters. However, except
for November 13, 1970, when a tropical cyclone connected with a huge tidal wave killed
around 400,000 people in Bangladesh, no severe catastrophe was reported during the 20th
century. In contrast to the moon’s obvious effect on the ocean, its gravitational effect on the
Earth’s atmosphere and thus on the daily weather is minute and can be ignored. There is no
influence and no connection between the moon’s phase and the Earth’s daily weather and
extreme events such as natural disasters.
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Historic and superstitious background
Friday has its semantic roots in the old German language, and means the day of God “Frija”,
who was comparable to the Greek goddess Aphrodite 7. Friday as a sad day derives from the
Christian religion, as the day of Jesus Christ’s crucifixion. Friday is the day of Armageddon
(“judgment day”) and the day of Judas’ death.
The number 13 was believed by the Greeks and Romans to be a symbol of death and
destruction. Agamemnon, the leader of the Greek assault on Troy, died on a 13th, as the saga
says. 700 years B.C. Hesiod warned to harvest on such a day. For the Christians the number
13 symbolises misfortune, mainly pertaining to the Last Supper, when Jesus dined with his 12
apostles 6. Predating Christianity, the Romans associated the number 13 with death and
misfortune. They believed that the number 12, the number of months in the year and the
number used to designate the hours in a day, suggests a natural cycle. To go beyond 12 meant
to be past natural limits.
Other sinister associations with 13 from the middle ages include that it is the number of
members of a witch's coven, one leader and 12 followers. In a Tarot card deck, the trump
numbered 13 is the Death card, a skeletal figure with a scythe. Friday the 13th is also the title
of a very popular horror movie from Hollywood (with nine, hopefully not more, episodes) 8.
Many hotels still do not have a 13th floor or the room No. 13, hospitals do not use this
number, and airlines try to avoid the number 13 as well. It was impossible to find previous
publications who describe the event of Easter Friday and the 13th day of the month.
The Moon’s phases and superstitious beliefs vary from region to region over the world. The
appearance of the moon changes because we on Earth see different parts of its surface lighted
by the sun. As the moon revolves around the Earth, the lighted side appears to us at different
angles. The phase you see on a particular night depends on the position of the moon in
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relation to both Earth and sun. Mostly the moon is honoured as a “Sun of the Night”,
brightening the darkness, especially when it appears as a full moon.
Various tales and myths are created around the full moon, such as the preferred time for the
appearance of vampires and for transformation into a werewolf. The transformation of a
human being (“wer” is an old Anglo-Saxon word for man) into a wolf during a full moon is
for the American Indians a symbol of our own life-long transformation 9.
In the Middle Ages the optimum time for blood letting could be predicted from the moon’s
position relative to the signs of Zodiac, which corresponded to human body parts 10.
The moon as a cold force has been described in many poems, such in this one :
“The moon has but a borrowed light, a faint and feeble ray;
She owes her beauty to the night, And hides herself by day.
No cheering warmth her beams conveys, Though pleasing to behold
We might upon her brightness gaze, Till we were starved with cold” 11
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Material and Methods
The aim of our study was to find out whether on Friday the 13th during a full moon people or
on a Good Friday the 13th are at a higher risk for injury .
From January 1,2000 to April 13, 2001, we compared the number of overall trauma
admissions to our emergency department on all full moon days and nights with the average
admission rate per day and the admissions of Friday 13 2000 and Good Friday 13 2001 .
The emergency department of the University Hospital Bern is the only tertiary emergency
unit in this area serving a population of about 750.000 and seeing approximately 30.000
patients a year. Sixty percent of all admitted patients are surgical cases.
Data collection was performed using the newly developed clinical software package
Qualicare™ (Qualidoc AG, Trimbach, Switzerland, www.qualidoc.ch). Qualicare is a
“relational database” which connects clinical data with categorised key words, thus allowing
immediate identification of patient groups with a defined diagnosis or other clinical aspect.
Furthermore the database provides links to academic and literature databases, medical
textbooks and statistic analysing programs. The data bank performed an automatic search
analysing all data of surgical and non surgical patients admitted on Fridays, Friday the 13th,
Good Friday and days with full moon using the built in computer calendar.
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Results
Between January 1, 2000 and April 13 2001 , 34,256 patients visited the University Hospital
Emergency Unit. Of those, 13963 were medical - ( average 29,9 per day ) and 20,293 surgical
emergencies ( average 43,5 per day ), 10,156 of them had either minor, moderate or major
injuries due to an accident .(See table 1)
On October, Friday 13, 2000, 16 patients and on April, Friday 13, 2001, 18 trauma patients
were treated in our unit. The average trauma admission rate on a full moon day and night has
been 19,3 patients. In comparison the average number of treated patients on a “normal
24hour shift “ has been 21,8.( See table 2 )
The accident data analysis showed no significant difference between full moon shifts and
Friday the 13th, compared to the average admission profile.
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Discussion
The superstitious coupling of Friday the 13th with calamity is very old in western culture. The
sixth day of the week and the number 13 both have foreboding reputations dating from
ancient folklore; their inevitable conjunction from one to three times a year portends more
misfortune than some credulous minds can bear. Folklorists say it's probably the most
widespread superstition in Switzerland and other parts of the world, as well. Probably the
same kind people believe in lunar myths because they have heard them repeated many times
by the mass media, neighbours , friends, doctors etc. Once many people believe something
and enjoy a significant amount of superstitious believes , they get very selective about the
type of data they pay attention to in the future. This a process by which a claim becomes a
strong belief through repeated assertion by members of a community. The process is
independent of whether the claim has been properly researched or is supported by empirical
data significant enough to warrant belief by reasonable people. Often, the mass media
contribute to the process by uncritically supporting the claims. More often, however, the mass
media provide tacit support for untested and unsupported claims by saying nothing sceptical
about even the most outlandish of claims. The superstitious person selects out favourable
evidence for remembrance and focus, while ignoring unfavourable evidence for a belief. If
one believes that during a full moon there is an increase in accidents, one will notice when
accidents occur during a full moon, but be inattentive to the moon when accidents occur at
other times. If something strange happens and there is a full moon at the time, a causal
connection will be assumed. If something strange happens and there is no full moon, no
connection is made, but the event is not seen as counterevidence to the belief in full moon
causality. Memories get selective, and perhaps even distorted, to favour a full moon
hypothesis. A tendency to do this over time strengthens one's belief in the relationship
between the full moon and a host of unrelated effects.
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In our study because of the rarity of Friday the 13th and a full moon occurring on the same day
or Good Friday on a 13th, and due to the absence of previous similar studies, a comparison
with other investigations could not be made.
We know from U.S and Dutch studies that the full moon phase does not significantly affect
the admission rate for trauma cases 2, 3. An other study proofed no relationship between traffic
accidents and the total or half synodic anomalistic lunar cycles and traffic accidents. No
sudden change on the day of the full moon or surrounding days was found 4.
Based on the results of our study, it seems that the same conclusion can be drawn once again
for the rare constellation of Friday the 13th and a concomitant full moon and Good Friday the
13th . Compared to the previous full moon shifts, we noticed no statistically significant
change in the hospital admission rate.
Fortunately or unfortunately for all “Fridophobics” and “lunatics”– those afflicted with a
morbid, irrational fear of Friday the thirteenth or full moons–a definitive conclusion can’t be
made because of the small study population. But it seems that our investigation supports once
again the “anti- theory” that Friday the 13th and a full moon and Good Friday the 13th in
defiance of all superstitious beliefs, are not associated with a higher risk for injury at least in
the Swiss capital.
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1983; 65(1): 21-41
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