DID HOMER DESCRIBE AN ECLIPSE IN THE ODYSSEY?
-------------------------------------------
John Pazmino
NYSkies Astronomy Inc
nyskies@nyskies.org
www.nyskies.org
2010 February 10 initial
2010 June 13 current
Introduction
----------
The Graduate Center, City University of New York, in February 2010
opened its new Initiative for the Theoretical Sciences. It began
staging public lectures on February 8 with 'Did Homer describe an
eclipse in 'The Odyssey'?' presented by Dr Marcelo Magnasco,
Rockefeller University. Future talks, both in evening and in noontime,
cover various sciences, including astronomy.
I with fellow NYSkies supporter Myrna Coffino attended the
Magnasco talk. It was in the Center's first floor hall, which was
filled to its 180 seat capacity many minutes before the talk began. I
suspect, due to strict seating rules, many latecomers were turned
away. Dr Magnasco stood at the podium and narrated his talk with
several slides, then took several questions.
The account here comes from the very lecture, the Baikouzis &
Magnasco article in Publications of the National Academy of Sciences
(1 July 2008), discussion with colleagues familiar with early Greek
history, and my own simulations of the Homeric skies. Dr Magnasco
collaborated with Dr Constantino Bailouzis, University of la Plata,
Argentina, on the Homer's eclipse project. Magnasco also reviewed the
previous version of this account and provided many solid suggestions
and improvements.
One point from Magnasco is that his first name is 'Marcelo' with
one 'l', for the Spanish name. It is routinely mixed up with the
Italian name 'Marcello' with two 'l's. So commonly was this mistake
that he had eaail aliases to map 'Marcello' to the correct 'Marcelo'.
I myself when composing this piece found the name cited both ways.
Homer
---
The author of the Odyssey, and the earlier Iliad, may not be a
real person! Altho by tradition the man, Homerus in Latin, supposedly
flourished in about 800BC, there is no supporting evidence for his
existence. In fact, by the time of the Classical Greeks, around 500BC,
there already was doubt about Homer with some authorities saying he is
a mythical person while others asserted he was real. And all assigned
discordant dates when he flourished.
Even if Homer was real there is no good evidence that he wrote the
two works. We are dealing with both a possibly fictional author as
well as a fictional litterature.
One common feature claimed of Homer is that he was blind. The word
for 'blind' could also mean 'a person who must follow'. While a blind
man pretty mmuch must have a leader, the meaning could apply to a
slave, captive, hostage. This gave rise to the idea that Homer was a
prisoner of war and then escaped or was released.
On the other hand, who ever did compose the Odyssey was definitely
an educated person. He knew geography, probably traveled around, and
fluent in language and poetry. He apparently knew astronomy!
In spite of the reasonable doubt about Homer and his authoring of
the Odyssey, it is prevalent to associate the man with the story. When
we speak of the period of Homer or of Odyssey, we really mean a
historical designation for the span of the 8th and 9th century BC.
One intriguing point, considered by Classical philosophers, is
that before about 600BC there are almost no individuals in the history
of astronomy. We know of the Egyptians, Chaldeans, Phoenicians,
Babylonians as a union. We know just about no particular Egyptian,
Chaldean, Phoenician, Babylonian astronomer, This supports the notion
that Homer is a fictional human like Paul Bonyan but not a full god.
He probably was not even a mythified real person like Davy Crockett.
The Trojan Wars
-------------
There was some massive calamity in and around the ancient town of
Troy (Ilium, Ilion) around 1200BC. This comes from archaeological
finds at the Troy VII site, But there are no vestigia of any of the
figures mentioned in the Iliad or Odyssey. No Achilles, Patroclus,
Hektor, Odysseus.
As fate fell to us, there is NO OTHER credible account of the Wars
beyond the Homer poems. Even the Classical Greeks owned up to the lack
of independent stories from the Wars. They relied on the poems,
knowing that they could be made up.
The date of the Wars, there being a series of campaigns lasting
some 10 years, is uncertain. It was under debate in the Classical era,
with dates ranging from the 1100s BC to 1300s BC. The physical
evidence favors the end of the Wars, when by the Trojan Horse the town
was sacked, to be in about 1200BC, plus/minus a couple decades. There
was no Troy culture after this era, the place being absorbed into
Greek rule by colonial expansion.
When I was in Turkey for the 1999 solar eclipse I visited Troy. I
saw a mockup of the horse and the waters now burying ancient Troy. The
shoreline migrated inland many hundreds of meters by the rise in sea
level over the millennia. No one knows what the horse looked like. The
mockup is about 7 meters tall with interioir stairs and benches to
show how soldiers could be packed into it.
I also saw many islands just off the Turkey coast that are
integral parts of Greece! I learned that on the Greece coast there are
many islands belonging to Turkey.
Turkey claims to have the most 'Greek remains', but this is
because Turkey is so much larger in extent than Greece. Greece is a
collection of islands, bays, and mountainous inland. Turkey, besides
being bigger, has vast flat areas, good river transport, long coasts
on Mediterranean ad Black Seas. The rougher mountain areas are in the
far eastern part of the country.
The Greek remains in Turkey are well cared for, as best as the
country's resources allow. Tourist may visit them under escort and
scientists may study them with no undue impediment.
The Odyssey
---------
Both The Iliad and The Odyssey are the oldest extant Western
written litterature. They marks a development of complicated
linguistic skill with deep mental gymnastics. The oldest written texts
of the poems are from about 800BC and this is often considered the
date of their creation.
There are several considerations here. First, a prime reason for
not having any earlier renderings of the works is that Greek writing
didn't start until about 800BC! Before then the Phoenician alphabet
was in use but there is no Greek original litterature from it.
At the same time, in the absence of a full writing system, stories
were handed down by oral tradition, much like they are in primitive
cultures today. In order to preserve the 'text' in its correct form,
the stories were told by song, dance, music, poetry, not by ordinary
discourse.
Spoken words can too easily mutate, distorting the text on each
instance of narration. In the poem, song, music, dance, the action and
sounds must be in proper order and kind, else the whole performance is
derailed. The erroneous part has to be replayed in the correct manner
in order to resume the story. It takes only one wrong note, step,
rhyme, cadence to louse up a performance.
The Odyssey is likely the first Western effort to put into writing
a long established oral story. The way this was done is unknown. The
author could have listened to an oralist and transcribed the story
onto paper. The oralist himself may have tried his hand at putting on
paper the story he so laborously recited. Perhaps he wanted to
instruct others to tell the tale to more audiences and needed a script
for them to follow.
The first appearance in around 800BC coincides with the
development of a true Greek writing system. The Odyssey could in this
case be about the very first major litterature by the newly exercised
writing skill. This notion is supported, by some scholars, by the
first appearance of comments and derivatives of The Odyssey (and
Iliad) within a few decades after 800BC. There are no such texts from
before then, showing that Odyssey probably wasn't yet in written form.
On paper it could be circulated faster, easier, cheaper to a wider
audience.
That no one prior to 800BC wrote about the oral story may simply
be due to the lack of a writing system capable of handling poetry. An
interesting theory I heard is that the Greek writing split off from
Phoenician IN ORDER to deal with poetry and put the Odyssey and Iliad
in paper. This may be pushing the envelope.
The work is a poem in hexameter, a common poetic cadence still
used today. It requiring fluency in the language and the arts to
select words and grammar to fit the cadence. The author clearly was
well lettered for this task.
The antiquity of the Odyssey was appreciated by the Classical
Greeks, who revered it as a great work of history. Recall that in
Classical times, the interaction of gods and humans was casually
accepted. Being that they chronicled the Trojan Wars, a signature
event in Greek history, they were preserved thru their era and into
ours.
As with any written instrument, there was some tinkering with it
over the centuries. The text we use today is the 'final' version from
about 100BC. It was neglected during the Roman years and resurfaced in
Europe in the late mediaeval period. There after it was in continuous
circulation thruout the Western world, being even today a reading
exercise in classical languages.
Culture
-----
There are several remarkable features of the Odyssey and Iliad that
only in the 20th century were revived in mainstream litterature. The
Trojans and Greeks, enemies in a brutal war, are treated in about the
same evenhanded manner. For a story composed from the Greek side, the
Trojans are not portrayed as monsters, hideous beasts, or otherwise
demonized. Due credit is given to bravery and heroism on both sides.
Modern war stories from the Cold War or the more recent regional
flareups are grotesquely, uh, slanted and biased.
Many major effective characters are women and lower-class men,
slaves, or workers. Not every thing is done by or for the kings and
court. Decisions and suggestions from women and slaves are treated
seriously by their higherups.
Today 'odyssey' means a long complex journey with adventures and
dangers overcome by the traveler. Other episodes became modern
sayings. The Trojan Horse incident in the Iliad, as one example,
became our 'Beware of Greeks bringing gifts'. It is also a type of
computer malicious code, appearing harmelss (the gift taken in) but
then damaging the computer (the soldiers pour out)
The contention over Helen is our 'She has the face that launched a
thousand ships'. A person may be defeated thru a single weak factor,
his 'Achilles heel'.
The ordinary modern person, learning such phrases in his daily
life, usually has no inkling that they came from a story almost 2,800
years old in written form and potential quite 3,200 since its original
oral composition.
The geography in the poems is not quite in line with modern times.
Ithaca may not be the present island by that name. Since the concept
of proper geography didn't exist yet, deviations of place names can be
expected, as they are in other cultures of Homeric and earlier times.
Some scholars think that certain places not obviously tied to current
places actually may be fictional.
Some scholars consider the eclipse as an anchor event in 1178BC
and trace back to the fall of Troy. They note the eclipse is the one
secure landmark in the looseness of other historical evidence. By
archaeological exploration at Troy, there was a mass destruction in
about 1200BC. Taking Odysseus's ten-year travels off of the eclipse
year yields 1190BC, which is, by chance or what, right on the money.
Homer's eclipse
-------------
The section relating to the eclipse is in the 20th book, chapter,
of the poem when Odysseus is traveling home to Ithaca island. Because
the story is a fictional work, the allusion to a solar eclipse was
formerly taken as a litterary feature with no real astronomy in it.
In Classical times several pundits claimed that the description is
that of a real eclipse, but no one suggested a particular one. Eclipse
mechanics weere not yet in hand.
In 1926 Schoch and in 1929 Neugebauer worked up that there was a
total solar eclipse over Greece and Turkey on 1178BC April 16. This
was a decade or so after the usually accepted date of Troy's fall and
within the time Odysseus spent in travel.
Classics scholars at first generally dismissed the idea that Homer
spoke of an actual eclipse. The poems are madeup stories. Astronomers,
on the other hand, accepted the idea, to the extent of calling this
eclipse 'Homer's eclipse'.
There was in fact a total solar eclipse on April 16th of 1178BC
passing over the Aegean Sea and lands of The Odyssey. While a manual
computation would be tedious, requiring parallel work by several
computers -- clerks who did maths on paper -- and careful crosschecks,
today the home astronomer can duplicate this eclipse with any goof
full-featured planetarium computer program.
Magnasco used Starry Night Pro, but any of the better ones, free
or commercial, may be applied. I myself used Starry Night Backyard and
Dance of the Planets, using Istanbul/Constantipolis as a general
location. Troy isn't listed in the choice of home locations. The
ancient Troy is actually offshore under water due to rising levels in
the Black and Mediterranean Seas.
The ground track of the Moon's umbra touched Libya, Tunisia, south
Greece, west Turkey, west Black Sea. The zone adjacent to this track
saw a deep partial eclipse. In the Aegean Sea the totality was at
about 12:15 local time, with a duration of about 4m30s.
During this eclipse, Jupiter and Saturn were left, east, of the
Sun, near a mutual conjunction. Mercury, Mars, Venus were lined up in
sequence to the west, right. Of the stars, likely only those in the
Winter Hexagon, plus Betelgeuse, would be visible. The Pleiades, a
couple degrees north of the eclipsed Sun, would be too dim.
This ASCII diagram clarifies the scene:
----------------------------------------------------------------
Saturn * * Jupiter :: Pleiades
O Sun
* Betelgeuse * Mercury
* Aldebaran * Mars
* Venus
* Rigel
* Sirius
# # # # # # # # # # # # # # # # SOUTH # # # # # # # # # # # # #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
----------------------------------------------------------------
Of special note is the set of all five classical planets within
the witness's field of attention. With but slight swing of the eyes,
they could be contemplated during totality with some appropriate
cultural significance.
No one disputes the existence of this eclipse. It's in Oppolzer's
and Meeus's compilation of solar eclipses and is routinely cited in
astronomy works about eclipses. Calling it 'Homer's eclipse' is by now
so embedded in the astronomy litterature even tho we don't know if
such a Homer ever lived.
Other evidence
------------
In addition to the specific comment that relates to an eclipse,
Magnasco found several other astronomy allusions that he believes
strengthen the case for the 1178BC eclipse. The items are:
-----------------------------------------------
* the Moon is new just before arrival in Ithaca
* watching Bootes, Pleiades, and Great Bear
* seeing Venus as morning star
* Mercury (Hermes) passes west by Sun (inferior conjunction)
* Posuidon crosses equator at vernal equinox
--------------------------------------------
All of these are in poetic language and use peripheral phrasing
into which their meaning is imputed. Magnasco pointed out that the
connection of Hermes, the Greek name for Roman Mercury, is
conjectural. More so is the relation of Poseidon to the equator
crossing of the Sun at the equinox.
Eclipses
------
A total solar eclipse is seen only along the ground path of the
Moon's umbra, at best some 200km wide. Globally, most eclipse paths
are over ocean or uninhabited lands. Until the late 20th century, the
ordinary home astronomer had little hope to see a total eclipse unless
he was within reach by regular travels to the path or was favored to
join an observatory trip. Public excursions to chase eclipses began in
the early 1970s.
Only if very near the totality path would a partial eclipse be
casually noticed with no foreword about the event. A slight darkening
of the sky could be treated as a weather factor and the Sun to the
bare eye still looks whole. An observer has to be within at least a
85% partial zone to see that something funny is going on with the sky.
But there is no excessive fear or dread and within a couple hours the
sky returns to normal.
In Homer's time and before total solar eclipses were events of
immense civil threat. They came with no warning as an act of the gods.
No one had the skills to predict when and where the next one comes.
Thales, living about 600BC, seems to be the first to say that an
eclipse was some natural event, altho he probably did not understand
the mechanics of Moon and Sun. The solar eclipse of 585BC was predicted
by him, with some probability that it would occur within that year.
There was nothing close to a modern computation of circumstances and
ground track. This 585BC eclipse stopped the battle of the Medes and
Lydians, but they know utterly nothing about the Thales prediction.
A competent eclipse theory requires that the Earth be spherical,
else the location of the ground track, or set of places under the
umbra, is all wrong. The Greeks at that time went along with the
Babylonian picture of a flat disc.
It wasn't until the 400s BC that serious effort began to organize
the motions of the planets using newly development maths. But eclipse
prediction were still far too crude, being good only to the year or
season. There seems to be no way a person, Homer or else, in 800BC
could figure out the eclipse for the Trojan Wars.
Simulations
---------
When simulating celestial events far in the past or future, a
properly constructed computer program must be employed. Many simpler
programs use 'trolley track' orbits. The planets circulate on a single
path with no regard for distortions by other planets. Such a program
is useless for a date even a century from the present. It should be
discarded and replaced with a astrodynamic model of the solar system.
Study the program instructions! It may give the span of validity,
like 'between 1000BC and 4000AD'. The program may reject a date entry
outside of this range or blithely accept it. It the latter case the
program will return ridiculous results.
Some astronomy programs ask if the date keyed in is Gregorian or
Julian. For simulations in the remote past the date MUST be Julian. A
Gregorian date before 1582AD is nonsense.
Astronomy programs may ask for early dates in BC form or negative
form. Read the instructions, else you will bo one year off in your
results.
delta-T
-----
An other feature of a good program is the delta-T factor. Because
of the secular slowdown of the Earth's rotation, calculations based on
a constant flow of time give discordant results for faroff dates.
delta-T is the offset between atomic time, which so far is the best
realization of a mathematical time, and Universal Time. UT is tied to
the rotation behavior od the Earth that carries the Sun across the sky
in the day-night cycle.
For past dates delta-T is known reasonably well for the last
couple thousand years and less certainly known before then. It is
worked up by comparing actual observations, like of solar eclipses and
occultations, with those computed by a uniform time scale. The
difference is the slippage of Earth rotation due to its secular
deceleration.
The problem is that in early eras events were poorly documented.
Their own error of date and hour can smother the uncertainty in delta-
T. In the Trojan Wars, likely no one had the mind to clock off Homer's
eclipse, like by a sand clock started then and running thru the next
sunset. A general statement that the eclipse occurred 'in the middle
of the day' is about as good as we ever will obtain.
For events banked off of the horizon it may be wise to factor in
air refraction and twilight. Both influence the visibility of stars
and planets, as may be reported (or not!) by ancient observers. These
factors are at best only recognition factors but they try to simulate
the instant observing conditions. The Odyssey mentions some stars near
the horizon or in twilight, so Magnasco included refraction and
twilight in his investigations.
Calendar
------
There was no 'Greece' as such in the early 1st millennium and
earlier, much less a 'Greek calendar'. Ancient Greece was a loose
collection of separate towns, some on islands, others in sheltered
coves and hills, who frequently warred against each other. They are
known n archaeology by their town or region names, not simply as
'Greeks'.
There was no such a thing as 'April 16' in 1178BC! Each part of
Greece and other parts of the ancient world had its peculiar calendar
and chronology. Many are still not well established and linked to each
other. For historical studies the Julian calendar is extended backward
thru the ages from 8AD, when Augustus Caesar put it on track for good.
There was no '8AD' in Augustus's day. Our current year count
started in about 550AD and it was off by a couple years relative to
the birth of Jesus. By our count, Jesus was born in (maybe) 2 to 6 BC.
The current year count did not use a year '0', altho zero was well
known in the 6th century from dialog with India and Arabia. Perhaps
the leaders who promulgated the year count didn't understand it? The
year preceding 1AD is 1BC, not 0.
This throws off calendar maths! To rectify the math, astronomers
use an algebraic count that includes a year 0. Years earlier than 0
are negative numbers. The value of an astronomy year is ONE LESS than
the history year. Homer's eclipse occurred in 1178BC or -1177.
To regularize ancient dates, the proleptic, backward extended,
Julian calendar is employed, regardless of the local citation of date.
The month names and day count overlay all other calendars, going back
to the indefinite past.
1178BC April 16 corresponds to many local dates, some of which we
still don't fully decipher. It is the date returned by astronomy
computations when working up celestial events in the remote past.
Leapday
-----
By fabulous luck, the insertion of leapday, arbitrarily begun in
8AD, just happens to come when the year number is evenly divided by 4.
This algebraic scheme keeps intact the 'rule of 4' for leapdays with 0
being the crossover from the positive, AD, years and the negative ones
before then. Year 0, 1BC, was a leapyear.
Mind well that altho Julius Caesar invented the Julian calendar in
the 40s BC, it was misused thruout the Roman world for decades. Each
province added leapdays as it wanted, much like the situation with
Daylight Savings Time in the United States before the 1970s. The
result was a dispersion of dates for a given event recorded in various
parts of the Roman Empire.
Augustus Caesar put the calendar in order, declaring the year we
now call 8AD to be a leapyear. There after there was no further
trouble with leapdays added every fourth year without fail.
Precession
--------
The sliding of the equatorial celestial coordinate over the
ecliptic coordinate is sometimes confused with the Julian-Gregorian
calendar dispersion. Precession affects the physical location of the
Sun and planets along the zodiac. not the dates, if the Gregorian
calendar is used.
A calendar ideally keeps the date constant for each step of the
Sun along the ecliptic, regardless of which stars he stands against.
This assume a solar, not lunar or other, basis for keeping dates. The
calendar year coincides with the circuit of the Sun around the
ecliptic. The equinox falls on March 21st, even tho that point on the
ecliptic gradually slides westward thru the zodiac constellations.
The drift of the equinox in the Julian calendar comes from the
a year that's slightly TOO LONG. When the Sun returns to the vernal
equinox the Julian year still has a couple seconds more to run out.
The next calendar year starts a little downrange in the zodiac so the
next vernal equinox occurs a few seconds earlier on the calendar.
The Julian year is 365.25 days long, with a leapday every fourth
year to make up the 1/4 day slippage. The Hebrew calendar is based on
this year length, as was demonstrated in the Birkat Hachama of 2009.
In that ceremony the vernal equinox can occur only at the quarter
points of the day: 18h (sunset), Oh (next civil day), 6h, 12h. After
four years, with one added leapday, the cycle begins over again with
the sunset indexed back to the initial date.
The real year, the circuit of Sun around the Earth (for the
geocentric view), is a trifle LESS. Julius Caesar knew this but
figured the difference is too small to worry about.
The extra seconds in the Julian year accumulate to cause a slow
slide of the equinox to earlier dates by quite 3 days in 400 years.
For past years, the equinox comes later by the same rate. Counting off
these years backward gives the Julian date of the vernal equinox in
the 1100s BC at April 1st. The vernal equinox point was 1/2 between
omicron and pi Arietis.
This situation was fixed by Pope Gregory's reform. Among other
fixes, century years are lean years except when evenly divisible by
400. 1600 and 2000 are leapyears but 1700, 1800, 1900 are not. This
operation removes the Julian calendar's extra 3 days in 400 years and
very closely keeps the calendar date lined up with the equinoxes.
The Gregorian calendar was NOT adapted every where at once!
Astronomy programs assume the step from Julian to Gregorian was
instantaneous the world over. The answers returned by these programs
can be wrong when compared to actual records. The last switch of a
country from Julian to Gregorgian came in the early 20th century.
Hermes and Mercury
----------------
In Greek astronomy the attachment of a god to a planet wasn't
firmed up until around 400BC. Before then the Greeks usually worked
with the Babylonian planets and let their gods have independent lifes.
If Homer was in this mind, the identity of Hermes the god in The
Odyssey with Mercury the planet is false. It's good agreement with
real astronomy events of 1178BC is then a complete fluke.
In the 800s BC Mercury was not yet recognized as a single planet
for both morning and evening star. It was still believed that one
thing shined in the evening and some other in the morning. It took
many centuries to figure out that it's one star that shifts sides
around the Sun.
Only after this was sussed out, along with the similar case for
Venus, were the pieces in hand for the Greek invention of a mechanical
and mathematical model for the solar system came about. That was in
the 300s BC and culminated with Ptolemaeus's work in the 100s AD.
Mercury's motion
---------------
I note here, for the common statement, that Mercury's greatest
eastern elongation is NOT the same as his entry into the retrograde
loop. I read in today's astronomy calendars that 'Mercury at greatest
elongation and starts its westward motion back to the Sun'.
The elongation is the maximum angular downrange distance from the
Sun. Mercury at this point is heading east at the same angular speed,
a degree per day, as the Sun. Then it slows to less than a degree per
day so the Sun catches up to it.
The station is when Mercury slows to zero degree per day. It then
in fact does turn westward to scoot around to the west side of the
Sun. It races thru inferior conjunction in the westward direction..
This retrograde motion is not well observable because it occurs in
daylight or strong twilight. There are no visible background stars to
track its motion against.
A parallel analysis applies to the elongation and station on the
west side of the Sun. Mercury's westward pace slows, and then stops,
to attain the station point. The planet begins a slow eastward
movement, less than 1 deg/day, but the Sun still outpaces the planet.
Eventually, Mercury's speed grows to 1 deg/day to stop the lead of
the Sun, this being the greatest western elongation. There after
he gains on the Sun with faster speed to decrease the elongation and
head for superior conjunction.
In the late 1990s the SOHO solar observatory was placed in the
Sun-Earth L1 Lagrange point. Its LASCO-3 camera continuously
photographs the Sun centered in a 7-degree radius field. The Sun is
blocked by an internal disc to reveal the corona, the main target for
this camera.
Background stars are in the field. When a planet is near
conjunction with the Sun it enters the field and can be followed for
several days. Mercury, and other planets, can now be watched in the
LASCO-3 pictures right thru their conjunctions.
For 2009-2010 are give here the key points in Mercury's wanderings
in the sky:
--------------------------------------------------
date in UT | event | elong | visibility
------------+-----------------+-------+-------------
04 Jan 2009 | East Elongation | 19 dg | evening star
11 Jan 2009 | East Stationary | 16 dg | morning star
20 Jan 2009 | Inferior Conjun | 0 dg |
01 Feb 2009 | West Stationary | 21 dg | evening star
13 Feb 2009 | West Elongation | 26 dg | evening star
31 Mar 2009 | Superior Conjun | 0 dg |
26 Apr 2009 | East Elongation | 20 dg | morning star
07 May 2009 | East Stationary | 15 dg | morning star
18 May 2009 | Inferior Conjun | 0 dg |
31 May 2009 | West Stationary | 17 dg | evening star
13 Jun 2009 | West Elongation | 23 dg | evening star
14 Jul 2009 | Superior Conjun | 0 dg |
24 Aug 2009 | East Elongation | 27 dg | evening star
07 Sep 2009 | East Stationary | 22 dg | evening star
20 Sep 2009 | Inferior Conjun | 0 dg |
29 Sep 2009 | West Stationary | 15 dg | morning star
05 Oct 2009 | West Elongation | 18 dg | morning star
05 Nov 2009 | Superior Conjun | 0 dg |
18 Dec 2009 | East Elongation | 20 dg | evening star
26 Dec 2009 | East Stationary | 17 dg | evening star
04 Jan 2010 | Inferior Conjun | 0 dg |
15 Jan 2010 | West Stationary | 20 dg | morning star
27 Jan 2010 | West Elongation | 25 dg | morning star
14 Mar 2010 | Superior Conjun | 0 dg |
08 Apr 2010 | East Elongation | 19 dg | evening star
18 Apr 2010 | East Stationary | 15 dg | evening star
28 Apr 2010 | Inferior Conjun | 0 dg |
11 May 2010 | West Stationary | 18 dg | morning star
26 May 2010 | West Elongation | 25 dg | morning star
28 Jun 2010 | Superior Conjun | 0 dg |
06 Aug 2010 | East Elongation | 27 dg | evening star
20 Aug 2010 | East Stationary | 21 dg | evening star
03 Sep 2010 | Inferior Conjun | 0 dg |
12 Sep 2010 | West Stationary | 15 dg | morning star
19 Sep 2010 | West Elongation | 18 dg | morning star
17 Oct 2010 | Superior Conjun | 0 dg |
01 Dec 2010 | East Elongation | 21 dg | evening star
10 Dec 2010 | East Stationary | 18 dg | evening star
20 Dec 2010 | Inferior Conjun | 0 dg |
30 Dec 2010 | West Stationary | 19 dg | morning star
---------------------------------------
The interval between the east elongation and station is about
twice that for the west, In the west case the Sun's own eastward
motion, carrying the planet with it, assists in 'pulling' Mercury back
on a eastward pace. The east case has the Sun 'pushing' Mercury
eastward, inhibiting his reversal to a westward direction against the
stars.
The rapidity of motion and interruptions by weather, twilight,
large Moon, closeness to the horizon all would impede routine
observations of Mercury. It was believed that the star of the morning
and that of the evening were two separate planets, given their own
names by ancient cultures
Great Bear
--------
Odysseus is instructed to sail with the Great Bear on his left..
This puts him on a eastward course. It, our Big Dipper, is also called
the Wagon in the poem. It does look like a wagon with the bowl as the
wheeled box and the handle as the drawbar. This today would be real
bad instruction for sailing! The Great Bear now wheels around the
north pole to stand in the north (under and above the pole), northeast
(right of the pole), and northwest (left of the pole). When above the
pole from the Aegean Sea today the Bear is in high north sky. From a
tossing boat it may be hard to judge that the Bear is a bit to the
north.
The north pole in 1178BC was about 3/4 way from Dubhe to Kochab.,
Polaris was then a too-far-away 'North Star'. The Big Dipper was about
10 degrees from the pole, not the 30 of now, and did not swing so
widely around the pole. It was more clearly 'to the left' more than
'high overhead' and stayed always in the north.
It's a bit odd that the other stars, Pleiades and Bootes, are
called on. According to Magnasco's interpretation, the Pleiades set by
nightfall, losing them as a guide. Bootes during the night shifts from
about east to about south, ruining it as a direction guide.
The Dipper alone, visible at all hours for being circumpolar and
it is so recognizable an asterism, it is a sufficient and helpful
guide for sailing.
In the Odyssey the reference to these stars is quite explicit with
little wiggle room for meaning. Yet it is of the least help in pinning
down the date for an eclipse because their configuration in the sky
repeats during every year.
The best Magnasco could say is that the season for the correct
alignment of Pleiades and Bootes is spring, which does fit the eclipse
in April.
No one later seems to comment that precession carried the Great
Bear too far from the pole to be by itself a reliable indicator of the
north compass point. One reason may be that precession IS a slow
process. By the Classical era 400BC thru 1BC the Dipper was still
pretty close to the pole.
The table here gives the approximate location of the north pole
and some figures about the Dipper's Bowl
--------------------------------------------------------------
| | location of | Bowl | azm | max
year | era | pole | dist | +/- | alt
-------+-------------+--------------------+------+------+-----
1200BC | Trojan Wars | Dubhe 3/4 Kochab | 17 d | 24d | 58d
800BC | Homer | Mizar 3/5 Polaris | 19 d | 26d | 59d
400BC | Hellenist | Alioth 3/5 Polaris | 20 d | 27d | 61d
1AD | current era | Alioth 2/3 Polaris | 21 d | 30d | 62d
1000AD | Middle Ages | Alioth 3/4 Polaris | 25 d | 36d | 66d
2000AD | today | at Polaris | 30 d | 43d | 71d
--------------------------------------------------------------
The Bowl is the mean location between Gubhe and Phecda.
There is a substantial effect due to precession. However, the
effect is a slow one likely escaping notice of short-lived cultures.
Certainly within a few human lifespans precession may be neglected for
simple stargazing. A star-finding guide from the early 20th century is
still useful in the early 21st.
Long-enduring cultures suffered from precession, as evidenced by
perhaps thousands of star-aligned structures thruout Europe and
Mesoamerica. The earlier ones were in their time found to be out of
line after a few centuries.They were either rebuilt, show by their
remains today, or abandoned.
These long-lived peoples also were bedeviled by the westward
slippage of the Sun's location within the zodiac. The vernal equinox,
for instance, took place against farther uprange stars over the
centuries.
In spite of these effects we have not one single positive
indication that any one prior to the Helenist Greeks actually
recognized precession. The very best so far we found was a dull
awareness that 'something strange' happened to the stars that upset
their older scriptures and structures.
Hipparchus in about 140BC looks like the first to properly
describe precession. He did have the advantage of geometry to realize
that a sphere rotating about an axis orthogonal to the ecliptic
replicated the observed displacement of the stars. His value of the
drift, 1 degree per century for ecliptic longitude, was too low but
for a first-cut explanation based on bare-eye astrometry this is
amazingly good.
Agreement
-------
Dr Magnasco presented a graphic timeline showing the closeness of
fit of the astronomy factors. Some years match well certain items but
fail with others. The only year when all four reasonably good items
(missing out the Poseidon/equinox) fit well is -1177 or 1178BC. He
looked at years 1250BC thru 1115BC to cover the range of uncertainty
for the date of the Trojan Wars.
What Magnasco did, as distinct from other scholars, is apply other
astronomy citations of The Odyssey and not fixate on the words about
the eclipse. When applying these five (four good ones) items, he found
that they all are satisfied if the eclipse is on 1178BC April 16. This
eclipse, if it happened ten years after Troy fell to the Greeks, puts
that fall in 1188BC, well within the historian's range.
The interesting point is that Magnasco COULD have found there was
NO agreement simply because the astronomy items were all made up, Or
they were ineptly assimilated from different years, maybe closer to
Homer's time, or just plain misunderstanded. The references are not
concurrent astronomy at all but allegorical comments about the gods
Odysseus engaged on his trip.
In such a situation, the scatter of agreement would be far worse,
with no hint of a good match for any eclipse. But he did find a good
fit for the 1178BC eclipse. He noted that this close fit can happen on
the order of once in about 2,000 years, Any other matching date is too
far away from the Trojan Wars.
What's missing?
-------------
With the whole Odyssey dealing with war, where is Ares, Mars, the
god of war? Apparently he's missing. During Odysseus's trip Mars is
too close to the Sun to see well, being a 2nd magnitude star shortly
after superior conjunction. It would shine in morning twilight and
pretty tough to spot. Yet is is in a direct line between Venus and
Sun, so a sailor could have spotted him with this alignment.
It is in high sky during the eclipse! However, being of 2nd
magnitude it probably escaped notice by a witness. In all eclipses I
ever saw, the faintest stars and planets were of at least first
magnitude. On some eclipses with an extra bright totality, only zero
and negative magnitude objects were spotted.
Also missing are Jupiter and Saturn, then in the western sky in
twilight. Both were planets with important significance when close
together. They were then approaching their mutual conjunction, which
could have an extra substantial meaning. They would have been
prominent in the west, above the Pleiades.
Who saw the eclipse?
------------------
Was the 1178BC eclipse actually observed? Weather could have
masked it. The totality track misses every cultural center running in
the 1100-1200 BC span!. The Hittites, Minoans, Egyptians missed
totality. It passed over other lands where no cognizant people lived
or cared.
Bear in mind that in the 2nd millennium and for centuries later a
solar solar eclipse was a terrifying experience. It's most unlikely
that people would come out and marvel at it, much less make careful
notes of its aspect. This was specially so when an eclipse came
without warning for a given location and there were scanty reports of
prior ones to hand.
The sky with no apparent cause gradually turns dim and the Sun
wanes in brilliance. Eventually by squinting a person sees the Sun is
no longer a full disc but has a huge gouge in it. The feeling is of
failing eyesight.
The air starts to cool off from its normal warmth in the
Mediterranean area. This can be a shocking chill, calling for cloaks
and other cold weather covering. Birds and animals act up. A blustery
wind springs up.
Then with a rush a dark cape or blanket sweeps over the world,
engulfs the scene, and the sky falls into a deep twilight! Some stars
may shine thru. The Sun turns into a shimmering glory with a black
central dot. The horizon is bordered by orange and yellow like a
panoramic sunset.
Then suddenly, the Sun flashes out, dazzles the staring witness.
The cape flies away from the land. The glory shrinks. The sky
brightens. The air warms up. This is damn well a warning from the
gods. Next time, the Sun may stay blacked out and the world with
freeze in darkness.
Against this apparition, would a Bronze Age people take the time
to carefully document the locations of the planets around the Sun?
With no competent writing skills to hand, how would they pass on this
record to the future?
The Egyptians had a mature hieroglyph system that we decipher
today, but they missed the 1178BC eclipse pretty widely. For them the
sky probably never showed any change of brightness and the Sun was
still too brilliant to see the Moon overlapping it.
It is possible, but unproved as yet, that boats were in the
totality path and their sailors brought back reports. With the steel
mind and nerve needed to sail the open sea in flimsy boats, a sailor
could possibly be brave enough to watch the eclipse. A navigator would
know the planets and possibly note which were in the sky. The event
would pass into the lore and legend of the seas.
The composer of the Odyssey could have been a contemporary fellow
-- maybe a participant? -- of the Trojan Wars. He heard of or saw the
eclipse after the sack of Troy. The close following of the eclipse
after the War probably had some special importance. He weaved it into
the tale.
By poetry or song or dance the story carried into the future to
Homer's time. Then, by some unknown and perhaps unknowable, person, it
was set into writing.
Trojans in space!
---------------
In the early 1900s asteroids were discovered that paced Jupiter in
his orbit, keeping roughly 60 degrees ahead or behind him. These were
the first realization of the libration points where small bodies can
maintain a quasistable motion under the balanced gravity of Sun and
planet. They were first described as theoretical features by Lagrange
and Laplace in the late 1700s.
The L4 Lagrange point completes the equilateral triangle with Sun
and Jupiter on the ahead side, forward in Jupiter's orbit. The L5
point completes the triangle on the behind, rearward, side. There are
three other Lagrange points, L1, l2, and L3, that have no application
here.
One massive misunderstanding is that the L4 and L5 points sit on
the planet's orbit 60 degrees from the planet. It just so happens that
Jupiter's orbit is nearly circular so the points are near the orbital
track. If Jupiter had a more excentric orbit, this concept is grossly
invalid. The points are on the equilateral triangle formed by the
instantaneous positions of Sun and Jupiter.
In 1904 Barnard found what at first he thought was the newly
discovered moon Phoebe of Saturn. He soon realized it must be an
asteroid because he then spotted the moon separately. It was later
designated 1904-RD but it moved far more slowly thru the stars than a
regular asteroid, as known at that time. With only the brief look at
it, the asteroid got lost, perhaps forever.
In 1906 Wolf found an other slow asteroid. He recognized that it
paced Jupiter about 60 degrees ahead of him. Further study revealed
that it was in the L4 Lagrange point of Jupiter. It became asteroid
588 Achilles. Other similar asteroids were soon found and the practice
sprang up to name these Jupiter-pacing ones after persons in the
Trojan Wars.
Those in the ahead Lagrange point, the L4 point, would be the
Greek side; behind, L5, Trojans. The entire set of these asteroids
became the Trojan asteroids. In the late 20th century, with far better
equipment and automated searches for asteroids, planet-pacing
asteroids were found at Mars and Neptune and suspected for Earth. In
addition, some of the tinier moons of Saturn were found to keep pace
with other larger ones.
They are genericly the libration or equilibrium asteroids because
they do not sit rigidly at the Lagrange points. They meander around it
the Lagrange point in a lazy orbit as if there was a gravity seat
there. Their action resembles that of a pendulum that's displaced off
of center and then let go.
Barnard's asteroid was soon lost and forgotten. In 1999 a new
asteroid 1999-RM11 was found. By careful simulations, it was tied to
several previously found and lost asteroids, including 1904-RD. Thus,
Barnard, without realizing it, actually found the first of the Trojan
asteroids, but Wolf was the first to find one and know it.
Altho stricta mente only the Jupiter group are the true Trojans,
the term is frequently applied to any set of tiny bodies in the L3 and
L5 points of other larger ones. However, all proposed names from the
Trojan Wars are reserved for only the Jupiter Trojans.
With the huge armies on both sides of the Wars, there seem to be
an ample stock of names for new asteroids. By yearend 2009 we had
about 2,500 Trojans on the Greek, L4, side and about 1,400 om the
Trojan, L5, node. Most are not yet named and are considered 'neutrals'
in each camp. We don't know why there is such an imbalance between the
two sides, since all are captured during impartial searches.
The Greek-Trojan naming system was adopted in 1908, after one
asteroid in the Greek camp was named for a Trojan and one in the
Trojan node was named for a Greek. The list here gives the first few
Trojans, discovered up thru year 1930. The ASCII diagram below the
list shows the location of the Trojans nodes relative to Jupiter and
Sun.
-------------------------------------
year numb name Gk/Tj remarks
---- ---- --------- ----- -----------
1904 12126 --- Tj 1904-RD = 1999-RM11
1906 588 Achilles Gk 1st recognized Trojan
1906 617 Patroclus Gk in L5 Trojan node
1907 624 Hektor Tj in L4 Greek node
1908 659 Nestor Gk Gk-Tj segregation adopted
1917 884 Priamus Tj
1919 911 Agamemnon Gk
1930 1143 Odysseus Gk
1930 1172 Aneas Tj
-----------------------------
The high number for 1904-RD results from the late day when its
orbit was determined, 95 years after discovery.
When an asteroid is found it gets a discovery designation. Only
when it has a secure orbit does it get a serial number. Then it
qualifies for a name, first by the discoverer and then by outside
proposals. As at yearend 2009, Barnard's asteroid 1999-RM11 is not yet
named, altho it had its definite orbit for over ten years as #12,126.
---------------------------------------------------------------
- - - L4*Gk
/ \ orbit motion
Jupiter orbit--/ \ /|\
| | |
| O o Jupiter
| Sun | |
\ / |
\ /
- - - - L5*Tj
--------------------------------------------------------------
It is now, 2000s, becoming possible to inspect the Trojans in home
telescopes by CCD imaging. They are at best 15th magnitude when
Jupiter is near opposition. Their large numbers, lazy motion, and
dimness require accurate detailed finder charts.
Trojans in New York State
-----------------------
During the American Revolution the US Congress induced enlistment
into its army by granting each soldier a 100 acre (400,000m2) land
grant when he finished his duty. New York was falling short of its
enlistment goal and added for its soldiers the reward of an additional
500 acres (2kn2). Enlistment quickly picked up.
This land was in a large region, some 8,000km2, in central New
York set aside for the veterans. It, the Military Tract, contained
Cayuga, Cortlandt, Onondaga, Seneca counties, plus parts of adjacents.
It was divided into 28 new townships, each further divided into the
plots of 600 acres (100 + 500, 2.4kn2) for the demobilized soldiers.
This was the first attempt at organized rural development in the
new United States, with provision for roads, public works, and
services interspersed among the veteran lands. The veterans took their
lands during the 1790s.
The townships were purposely named for Greek (and Roman)
characters, some from Homer's time! A few were named for British
writers (in the Revolution?, go figure). The townships, surviving
today, are:
------------------------------------------------
Townships in the NYS Military Tract of the 1780s
------------------------------------------------
1 - Lysander 8 - Aurelius 15 - Fabius 22 - Ulysses
2 - Hannibal 9 - Marcellus 16 - Ovid 23 - [Dryden]
3 - Cato 10 - Pompey 17 - [Milton] 24 - Virgil
4 - Brutus 11 - Romulus 18 - [Locke] 25 - Cincinnatus
5 - Camillus 12 - Scipio 19 - Homer 26 - Junius
6 - Cicero 13 - Sempronius 20 - Solon 27 - Galen
7 - Manlius 14 - [Tully] 21 - Hector 28 - [Sterling]
------------------------------------------------------------
The British names are in bumpers. Since the Revolution, new towns
within or near this Tract often were named for Classical places and
people to continue the nomenclature pattern.
Conclusion
--------
Dr Magnasco's talk was a solid attempt to apply astronomy to a
litterary work of unknown authorship and unknown age. Is this valid,
if such works are made-up stories with freely embedded mentions of
real or plausible events?
In the lecture it seemed as if Magnasco demonstrated that link
between the eclipse and Homer. In the Baikouzis & Magnasco article
many of the conclusions are stated as conjectures. In the article the
two authors are careful NOT to declare the case solved.
News items about Baikouzis & Magnasco in summer 2008 read as tho
tho two were the first to uncover the eclipse and that its ties to the
Trojan Wars is a done deal. The allusion in th Odyssey was known as
Homer's eclipse long before the current work.
I came away with the feeling that the bulk of the audience lost
the essence of the talk for want of astronomy background. This came
from noticing that most attendees around me were daydreaming or
moping. Oh, yes, many others were listening intently.
The bulk of audience scooted soonest the applause died down,
leaving only a few to banter with Magnasco. He spoke for about a half
hour beyond his allotted time, yes, with the OK of the host. This
contrasts with many other overtime shows I attended that held a
substantial audience in its seats or around the speaker at the podium
long after doors were scheduled to close. In such cases it was the
facility crew that shooed the audience out to the street.
In spite of the apparent disconnect between the speaker and
audience on this instance, for astronomers, archaeologists,
anthropologists, historians, Magnasco's work could lead to some
fascinating new avenues of inquiry.
Let's suppose that, by some future means, The Odyssey does in fact
relate to a real eclipse, Let's further say it is the one of 1178BC.
Then our ideas of the astronomy sophistication in the Bronze Age, plus
the capacity to make sensible objective descriptions of so rare and
fearsome an event as an eclipse, must be revised.