Planets, Moons, Stars
& The Cosmos
5/15/2007 - The only portion of this Storyboard which is currently relevant to MWM's books is the section on the Moon and its Cycles. The other sections will not be developed as themes in MWM's works, they serve here mainly as collections of interesting stuff which are well worth wishing on passers-by. Mandeville has a ton of additional stuff which could be included, but this is a low personal priority. These sections initially will primarily be used to cut and paste in running notes on iway research "finds", thus the content in these subsections may lack integration, style, consistency, and coherent explanation.
Table Of Contents
The Moon & Cycles - Monthly Full Moon (Synodic), Monthly Perigee/Apogee (Anomalistic), 18 Year Saros Cycle
Summary of Major Findings
Background Information & Knowledge/Data Sources:
Every planetary body, including the Earth, is surrounded by its own gravitational field, which exerts an attractive force on any object. This field is proportional to the body's mass and varies inversely with the square of distance from the body. The gravitational field is numerically equal to the acceleration of objects under its influence, and its value at the Earth's surface, denoted g, is approximately 9.8 m/s². This means that, ignoring air resistance, an object falling freely near the earth's surface increases in speed by 9.807 m/s (32.174 ft/s or 22 mi/h) for each second of its descent. Thus, an object starting from rest will attain a speed of 9.807 m/s (32.17 ft/s) after one second, 19.614 m/s (64.34 ft/s) after two seconds, and so on. According to Newton's 3rd Law, the Earth itself experiences an equal and opposite force to that acting on the falling object, meaning that the Earth also accelerates towards the object. However, because the mass of the Earth is huge, the measurable acceleration of the Earth by this same force is negligible, when measured relative to the system's center of mass.
Nun - The Cosmic Background
Our Solar System - Ra's Boat Of A Million Yearsdigitized plates from Harmonia Macrocosmica
Very groovy and extensive University of Utah portfolio of digital images of ancient systems of astronomy
The Inner Planets
Courtesy Jet Propulsion Lab
The Inner Four Planets set inside the ring of the asteroid belt and the orbit of Jupiter. Each point of light is an actual representation of a planet, asteroid, or comet (plus the Sun of course), set within a true scale of distance as of April 1. The positions of all numbered asteroids and all numbered comets in JPL's small-body database are shown (as of April 1, 2007 ). Asteriods are yellow dots, comets are the pale blurry smudges. We are looking down on the Solar System, overlooking the "North Pole" of the Earth.
As can be seen, our Solar System is a pretty busy place.
The next pix is a view of our solar system seen from "the edge". The orange line is the plane of the ecliptic (Earth's orbit plane).
Courtesy Jet Propulsion Lab
Comparisons Of The Four Inner Planets (NASA)
Left to right: Mercury, Venus, Earth, Mars
Earth's Magnetic Bow Shock Formed Against The Solar Wind
The trail is MUCH longer, can extend out to the orbit of Mars
Earth's Orbital Variations
Chart above is a digital image in the Marriott Library at the University of Utah. copyright 2000 by the Library,all rights
from HarAstronomy; Stars -- Atlases; Astrology; Constellations; Planets -- Observations; World mapsOne of 29 double-folio plates digitized from Andreas Cellarius' Harmonia Macrocosmica. The second edition was published in 1661 and is a celestial atlas of the Ptolomaic, Copernican, and Tychonic wo
The Moon & Its 18 Year Saros Cycle
go here to integrate daily dynamic images about the moon
Introduction To The Primary Lunar Cycles
Like The Earth, the Moon repeats a very simple monthly orbital pattern as it spins in its never-ending swan glide through the solar system. Also, in the same manner that the Earth's orbit is variable, the Lunar Orbit fluctuates and varies in its orientation around the Earth, in its distance from the Earth, and in the tilt of its track around the Earth. These orbital variations combine endlessly to make each monthly orbit unique in its exact characteristics, even though superficially each orbit is much the same as all the others.
The three fluctuations of orientation, distance, and tilt in the orbit produce three distinct cycles of variation which can differ in length by as much as 8% and in the direct gravitational influence upon the Earth by as as much as 25%. This difference sets up a rapid rate of precession (orbit-speak for slippage) in their timing during which the cycles continually fall into and out of mutual synchronization every year.
This complex three-way precession pattern produces a complex influence over the Earth. The cycles create the tidal forces in the oceans, the crust, and in the Earth's spinning wobble and their precession makes the tidal forces wax and wane in strength by highly variable amounts day by day, month by month, year by year. Everything is always the same, in a certain cosmic sense, but not really exactly.
The complexity of the way the cycles interact makes the variations difficult to visualize. The charts and graphs provided below will help demonstrate these cycles and how they correlate with the tectonic activities in the Earth. To get the interconnection, it helps mightily to use the unique name of each of the three primary lunar cycles. The basic orientation of the orbit is called the Full Moon Cycle or the Synodic Month and its length is xxx days ). The distance of the orbit is called he Perigee/Apogee Cycle (technically called the Anomalistic Month with a length of xx days and a variation in distance between the Earth and the Moon of about 356,000 to 406,000 kilometers ). The tilt of the orbit is called the Nodal Month and the length of time for the Moon to orbit through two nodes back to its starting point is xxx days.
Comparisons Between Earth & Moon
Visible Size Comparisons Of The Moon At Perigee & Apogee
Libration Of The Moon - Apogee
Careful comparisons reveal that the southern crater appears to shift to the north and to the left during Apogee.
The Perigee Cycle and the Orbital Tilt's Nodal Month are the primary source of the complexity in the Moon's influence upon the Earth. Both of these cycles have large swings in their power relationship with the Earth and thus the synchronicities of these two cycles have profound effects on the oceanic and crustal tides. Humans have needed to understand these since the dawn of professional sailing, which is now widely estimated to have begun several millennia ago. Most probably, the sailing professions of the ancient empires were the first primary students of the heavens and the many moods of the Moon. In some respects, Stonehenge is a Lunar calculator, predicting the tides in the English Channel may have been an important adjunct of its purpose. Since these cycles are difficult to visualize and remember, an entire industry of Ephemeris calculators and tide table publications has emerged expressly in the modern age to keep track of these Lunar variations.
The least understood cycle is the Nodal Month Cycle but we can already see enough in the graphs below to realize that it may be the key to understanding the why, how, and timing of the largest tectonic events. As a result of the 5.3 degree tilt in the Lunar Orbit (relative to the Earth's orbit, which is the plane of the ecliptic), the Moon's influence shifts its focal point by some 56 degrees over the surface of the Earth nearly every month. When the Moon's orbit intersects and passes over the Earth's orbital plane, the two points on the plane of the ecliptic which the Moon passes over each "Nodal Month" have been anciently known as the "Nodes".
In about one week of time, the Moon's orbit then brings the Moon to a position which is 5.3 degrees above (or below) the plane of the ecliptic. Then the Moon slowly moves back to the Earth's ecliptic plane, crosses over the opposite Node, and begins a journey on the other side of the Earth's ecliptic plane.
Since the Earth's actual daily spin is also tilted to the plane of its orbit around the Sun (the plane of the ecliptic) by 23.5 degrees, the two "tilts" of the Earth and the Moon combine to permit the Moon to be overhead as far north of the Equator as 28.5 degrees, or as equally far south of the Equator. The exact location varies significantly between these extremes day by day. For complex orbital timing reasons, the extremes of the cycle even vary, month by month, even year by year.
The three Lunar cycles combine with a fourth cycle, the Earth's own annual Solstice Cycle, which shifts the orientation of the Earth's poles away from and then back towards the Sun every six months.
Since all of these cycles are of different lengths, the lunar cycles endlessly precess in time with each other and with the Earth's Solstice cycle. They continually fall into synchronicity (such as when their beginning points coincide and then back out again in cycles which range from 18 years to over 1000 years. The cycles endlessly combine in unique ways but it turns out that fluctuations in the "synchronicity" of their cycles have a regular cycle as well. Thus the cycles play out in a larger scheme of repeating cycles which beat out a cosmic tune which has been playing the same essential tune for as long as the Moon as been twined with the Earth. These larger cycles, collectively known as the Saros Cycle, are of profound importance to understanding the geology of the Earth.
There are many other minor perturbations in the orbit of the Moon which occur daily, monthly, annually, or in even the longer Saros Cycles. These "nutations" arise in response to a large number of influences in the solar system, they have many names, but these have essentially no notable influence on anything of importance to climate or Earth's tectonic engine.
With just this brief introduction, it is rather obvious that the cosmic orchestra which is playing the beat of the universe for us in the orbits of the Earth and the Moon has a very complex rhythm structure which is a little difficult to "get" at first. In fact, few get it and that's a profound shame. It needs to be gotten, the Science of the Earth MUST begin with an understanding of the primary Earth/Moon orbital cycles. These cycles define exactly the vortex in which all local matter, us, is "falling" through the universe. All the energetics of relative motion and mass effect in the Earth connect in this four dimensional vortex.
Through these four cycles, the Moon is the primary driver of Earth's vast tectonic engine. The rapidly and radically changing angles and distances of the Moon's force fields, interweaving with the nearly constant gravitational force field created by the Sun, is the hammer and chisel which forges and sculpts the surface of the Earth. The 56 degree swing of the Moon's location (Nodal Month) over the surface of the Earth and the 25% variation in its gravity field strength (Perigee Cycle) are like vast cosmic pistons pounding continually on the Earth's tectonic plates.
Most of the energy pushing the vast tectonic movements of the
crust is in the spinning mass of the Earth itself. Without the Moon,
the gravity field of the Sun would lock this spinning energy into a frozen
"standing wave" pattern which
would change very little through time. The crust would be virtually
inert, the surface of the Earth would all be a shallow sea lying
over uniform layers of muddy sediments, all these in turn lying
over layers of granite and olivine and occasional lava sheets
generated by asteroid strikes. Earth would be a water world,
probably with no visible land.
In its relative daily motion, which is mostly the Daily Spin of the Earth, the surface of the Earth is pulled from East to West by the Moon's tidal gravity force as it passes overhead to the west. Most of this motion, of course, is actually the motion of the spinning Earth spinning from west to east. As the crust spins to the east, the Moon's pull stretches it and rumples it up in bunches towards the west, just exactly as it does with the oceans when it creates the daily tides. With the oceans, the Moon bunches the water into tide stacks which range from inches to many feet, depending upon the time of year and the synchronization of the Moon's primary cycles. With the surface of the Earth, Lunar tides in the crust have been measured to be as much as a few centimeters high.
This dynamic forces all the crust of the Earth to slowly creep and gradually move. By progressively lifting the Rocky Mountains over the Pacific Ocean Bottom, this cosmic engine created the Americas and it creates the rapid rates of upliftment and subduction which are found along the eastern edges of the thick, deeply lying tectonic plates of Eurasia and Australia, and to a more limited extent, Africa.
In its monthly orbit, the Moon rotates around the ecliptic of the Earth (the plane in which the Earth orbits around the Sun). As it rotates, the Moon's tidal forces alternatively add to the gravity of the Sun (during the New Moon) and subtract from the gravity of the Sun (during the Full Moon). This produces a large monthly fluctuation in the gravity tidal forces working in the crust of the Earth, as well as a fluctuation in the actual rotation speed of the Moon.
This fluctuation acts like a vast pump which inflates and deflates
the Great Rift on a regular monthly basis. The Moon rends the
entire surface of the Earth into two separating halves in Great
Rifts (mid oceanic ridges) which run through the middles of the oceans. Think of this as the
primary geotectonic quantum flux. When the Moon is Full, it works
in opposition to the Sun which is on the other side of the Earth
during the Full Moon phase. The two easily pull apart the Great
Rifts in the bottoms of the oceans during the Full Moon, allowing magma to squeeze up and out of the Earths mantle
in vast and invisible quantities to produce equally invisible
volcanic activity. Day in and day out, this activity is easily 1000
times greater than the surface volcanism which humans can observe
and occasionally it is much as 1 million times greater.
When the Moon is New, in other words when the Moon is aligned up between the Sun and the Earth, all gravity vectors combine in one force and the over-all global effect is compression in the crust, not a pulling apart. Accordingly, during the New Moon the greatest tectonic activity can be found in the long subduction zones. These zones line the edges of the tectonic plates where the compressive force works to grind the edge of one tectonic plate over another, compression forcing new geometry in the geo-structures.
The compression gradients can be thought of as slow-moving waves and tides which induce motion in fragments in the crust of the Earth (tectonic plates both vast and small. As the fragments move, they grind against each other and deform the crust at their edges, thus giving rise to the Earth's mountains. Bouyed up on the Moon's gravity fields, continents heave up vast high plateaus to tower over even vaster ocean depths.
Since the Earth's surface is so complex in composition, material, shape, fault zones, size and shape of tectonic plates, orientation of the Great Rift, and so on, it should not be surprising to learn that the dynamic energy fluctuations produced by the Moon tend to create probabilities in certain kinds of results at certain times, but not exclusive conditions. In fact, both compression quakes and rift (expansion) quakes can be found every day, somewhere. What changes is the dominance of one type over another in major areas with timing phased to the orbits of both the Earth and the Moon. This dominance can be seen at times in both magnitude of quake activity and frequency of quakes.
Adding greatly to this complexity is the wide degree of
latitude in which the Moon's focal point can shift. The
orbital tilt or inclination to the spinning equator can shift plus
or minus 28.5 degree within as little as two weeks for a total
spread of 56 degrees. This rapid rate of change must induce a
very powerful shape-shifting wave in the same time domain to "nudge"
the continents along in their accustomed paths of motion.
Leading up to the New Moon in mid May 2007 , the daily lunar rumple-crumple factor was the strongest pattern in earthquake activity. This was expressed most strongly, as it always is, in the western Pacific against the eastern edges of Eurasia/Australia. The daily tidal "waves" in the crust of the Earth stack up and "break" against this vast bulwark of deeply lying continental materials more than at any other area. Early May 2007 between the Full and New Moons was no different and thus most of the 4+ quakes of this period were found in this zone. Very few occurred in the western edge of the Americas during the two week period before the May New Moon.
Then came the New Moon. The compression forces quickly consolidated and began dominance. Seven 4+ quakes struck within 48 hours of the New Moon along the vastly long subduction zone of the western edge of the Americas. They of course were not alone. Compression zones in Eurasia experienced an increase in 4+ quakes as well.
Two days after the New Moon, as the expansion phase was slowly beginning. a 4+ expansion quake struck in the Great Rift in the extreme South Atlantic
And so it goes, since time immemorial. This Full Moon or Synodic Month Cycle expansion/compression fluctuation is a pumping force which flexes the Great Rift on a regular monthly basis. Think of this as the primary geotectonic quantum unit. This is mainly how the Earth splits in the Great Rift, produces slow moving earth shape-shifting waves/tides, generates new crust, rumples from east to west in north to south trending mountain ranges, uplifts continents, downwarps and subducts ocean bottom fragments such as Baja, Nazca, Gorda, and others, and finally how and why the shape-shifting waves break against the deep continental mass of Eurasia, producing the deep subduction zones in which the "excess" crust disappears into the mantle.
2+2=4 = this is how the Earth works.
The Moon's orbit, though it seems so simple and benign, is, as we can see in fact, very complex and its play on the surface of the Earth makes for a VERY complex Earth. Accordingly, the influence of the Moon has been difficult to read before the era of online databases. If the play of forces were as simple as a monthly expansion and contraction by the phases of the Moon, the pattern would have understood a long time ago. But the other two orbital fluctuations (the Perigee and Nodal Cycles) constantly add and subtract their influences to make a complex play against an even more complex cosmic backdrop.
And thus the confusion arises. Sometimes, for instance, the greatest rifting does not occur during the Full Moon. It occurs when the Moon is at its closest approach to the Earth. Sometimes very few compression quakes can be observed during the New Moon but will be prolific during a Full Moon. And every 18 years, certain regions will experience a sudden outpouring of large quakes and then fall silent again. And so on. The fabric of this play is so rich in detail, humans are still confounded by the details and have not quite caught on to how the Wu Li Master dances out the life of the Earth.
It does not help to be highly specialized. Until this point, scientists have tended to work within too limited of a frame of reference to tune into the dance. To catch the drift, they need to get a little cosmic.
The main thing which IS certain, is that it all does flow with the dance of the Wu Li Master. The key to the mystery is learning to observe how the three primary lunar cycles combine and subtract their influences over the Earth's Solstice Cycle, Longitude by Longitude, Latitude by Latitude, in the grand lunar cycle which is known as the Saros Cycle.
The Rubber Band Analogy
Many geophysicists think predicting specific tectonic events is largely impossible. If this is true, then Plate Tectonics is largely an unpredictable process, something we are doomed merely to watch with very little foresight about what is going to happen next.
Most quakes, such pessimists observe, really can't be correlated with anything specific in a linear cause and effect relationship, thus as far as we are concerned earthquakes and volcanic eruptions are "chaotic events " which occur randomly. Some cite the example of studies which show that the planet Uranus is usually overhead when major quakes strike in certain areas. This is apparently true in some instances but the problem is that Earth rotates so that Uranus is overhead once every 24 hours over every point of the Earth and mostly NO major quakes occur when it is overhead. This makes the position of Uranus worthless as a signal of an impending major earthquake.
They same can be said about any other posited connection with heavenly bodies, the Sun, the Moon, etc. Major quakes do occur when they are in certain specific relationships but only infrequently in any given area or region. And quakes will also occur at apparently random times, anywhere.
Such quake chasing is probably asking too much for "earthquake prediction". Specific quake events probably never will be specifically predictable to a real time frame with advance warning of more than a few days, or possibly a few weeks.
Some geophysicists have taken the tack of studying the frequency of seismic activity in any given area to define in some sense "the apparent cycle" or statistical probability of the reoccurance of another major quake. Many government-sponsored scientists are using this approach to come up with a socially responsible method to use science to foresee tectonic events which may be harmful. California and Japan are well down the road with such predictions, to the extent that catastrophic quake events have been given time horizons for some of the major faults. Based on the frequency of previous quakes for a specific fault, it does not take much imagination to suppose that the frequency will continue to hold into the future.
Using such logic, most geophysicsts would concur that the western North America, from Alaska to Baja, is "due" for 9+ quakes in all of the major coastal areas during the next 25-100 years. California scientists expect a "big one" in Northern California during the next 25 years and state officials are already "planning" for it. The same is true in Japan. Scientists in the Pacific Northwest are also coming on board as they think through the implications of Plate Tectonics and the historical signatures of the past several millenia. They now concur that another 9 + quake could easily bisect the Puget Sound region once again, at any time.
Such predictions are purely the projection of past frequencies to define statistical probability timelines into the future. They are far from predictions of specific events. For generating specific warnings about a specific fault or area, geophysicists are studying, devising, and testing a variety of concepts to measure "precursor signals" of an impending event. Both volcanic eruptions and earthquakes create telltale signatures which, more likely than not, humans can learn to read. Such precursors may, in the case of volcanoes, provide warnings years to several months in advance, with the onset of major eruptions likely fore-seeable a few weeks in advance. Theoretically the impending quake should be seen at least a few days in advance and possibly for major quakes the precursors may provide useful warnings a few lunar cycles in advance.
The most objective signals of an impending quake, and any volcanic eruption, will most likely come from radical shifts in the electromagnetic properties of the associated fault lines and the adjacent areas in the weeks and days leading up to the event. When the stress factors have built up enough to a certain point, pressure acting on the substantially silconized geo-matrix of the fault zone produces what we might think of as "plasma-faction" in the atomic lattices. The material does not so much "crack" as it electrically "liquifies" the matrix. This produces a sudden and radical drop in friction and voila!, the Earth is free to move suddenly through the "rarefied" zone. And so it does.
The build-up of pressure to the point of plasma-faction generates various signals which scientists are learning to read. The key to using the signals is to wire the fault zones well, rigorously record the readings through time, and learn how to correlate the readings with events. All this will take a lot of empirical experience with each specific fault zone, accordingly specific predictions of impending big earthquakes will not come cheap. It is also quite possible that the signals will not be easy to use the first time around to predict a large quake. It will take hindsight to be certain what the signals probably mean.
At best, even this approach is likely to be frustrating. The build-up to point plasma-faction may come and go, like Uranus. It may come and go many times in a century before the fault finally gives way to create a quaking in the crust.
To understand why, consider the lowly rubber band. It may be the perfect analogy to the elastic behavior of the Earth. Consider first the outer crust. It is is highly crystalline and brittle. It has no "global" level strength. Its apparent rigidity is more bluff than real. The vast inertia of the Earth spinning rapidly through its compressing gravity well holds the crust rigidly in place. But disturb that spinning mass only a very little, speaking relativistically, the crystal easily snaps.
Now consider what keeps the crust of the Earth stuck together. Other than the spinning inertia, what holds the crust together is its taffy underside. Beneath the crystalline "hard" surface, the Earth has a highly sticky ropey layer of magma or crustal re-melt which is apparently at least 25-50 kilometers thick, probably as thick as nearly 400 kilometers in some areas such as the most active subduction zones. It acts like well-cooled taffy. It gives just enough to allow the Earth's shape to alter slightly, or the continents to move very very slowly, but this "give" does not weaken the overall crust. In fact, is is far stronger than the brittle, glass-like hard surface. It is elastic enough to bend with the wind of tectonic stress gradients flowing through the crust without breaking.
Now let us work the elastic Earth like a rubber band. Let's alternatively stretch and expand the rubber band, now let its compress back into its natural state. Let us keep expanding and contracting the rubber in the band. After awhile, what happens. More and more cracks appear in the rubber. After progressive working.... the rubber band gets more and more stretched and frail. Its binding forces have been broken in multiple places and suddenly, with the next flex just like ten thousand before it, the band fails and snaps under the load. Did "the" flex snap the band? Well, yes, but then, not exactly just that one.
Major Earthquakes are the "one thousandth event". Great Earthquakes are the "ten thousandth event". At no point in the sequence is the "snap" predictable in the next flex. But the snap is entirely inevitable. Frequency is obviously the key issue. Frequency equations of failure for the various materials and loadings of the crust, combined along with databases of profiles of "failure signals", may eventually make short term predictions of earth quakes somewhat reliable. But it could easily take humans another 50 years to get coherent enough databases and models together to make a real science of crustal "failure".
In the meantime, there is another method. It is the same method as the ancients who built elaborate "Stonehenges" to record the passage of time and track the Sun and the Moon. It is forecasting the periods of synchronicity in the main orbital cycles which create the times of the greatest tidal forces and the times of the maximum compression and expansion. Though the relationship in time with the occurrence of modest or greater earthquakes is not 1:1, more probable than not the most destructive quakes will occur within these windows. If this "watch" is integrated closely with "signals" research, scientists may learn within a generation or less how to "catch" the big ones.
How The Lunar Cycles Produce The Saros Cycle
Forecasting the synchronicities begins with the Perigee and Nodal Cycles. These combine in the 18 year "Saros Cycle" to predict the times of the greatest expansions and contractions in the Earth's crust.
Because the Moon is rotating around the Earth
even as the Earth is moving around the Sun, the Moon's orbit has a
major distortion in it, making it an egg-shaped ellipse with an
"eccentricity" of 5.49%. This is large compared to the
other major bodies in the Solar System, excluding the incomparable
Pluto. This eccentricity ratio is not nearly as useful
as realizing that the Moon changes its distance to the Earth by as
much as 8%-12% during each month. Since gravity varies in
proportion to the inverse square, this produces a shift in the
gravity vector by ~25%.
These numbers vary each
month in natural fluctuation and also by how you calculate the base
reference, or the average elliptical orbit, which is
anything but close to symmetrical).
the Sun's gravitational
field increases the eccentricity when the orbit's major axis is
aligned with the Sun-Earth vector or, in other words, the Moon is
full or new.
Known as the Perigee/Apogee Cycle (called the Anomalistic Cycle in old-fashioned astro-speak), Perigee is the moment when the Earth is closest to the Moon at about 356,000 Kilometers. Apogee is when the Moon is furthest from the Earth, at about 406,000 Kilometers. The mean distance is 384,401 Kilometers but this does not mean much because the Moon is seldom there. The Perigee Moment obviously brings greater gravity pull upon the Earth, the Apogee Moment less.
The increased gravity during Perigee increases the rate of the daily tidal "rumpling" of the Earth. If it occurs during the Full Moon, it adds to the rate of the monthly spreading of the Great Rift. And if it occurs during the New Moon, the increased gravity adds real power to the monthly compression in the subduction zones. Apogee phases have of course the opposite effect.
Now where this gets complex is in the precession of the cycles. The Perigee/Apogee Cycle precesses, or in other words is continually slightly shorter in time than the Full Moon Cycle. In fact it is about 2.3 days shorter, thus Perigee continually earlier and earlier in any given Full Moon Cycle. This means that Perigee adds power to the Full Moon and then precesses during the year to eventually add power to the New Moon. Thus each year there are a few Full Moons (generally about three) which are very close in synchronicity with Perigee and generally there are about three New Moons in synchroncitiy with Perigee. The same is true of Apogee, which pretty much accounts for the year.
This means we have Expansions and Compressions in the crust of varying potency and impact each year. In fact, this makes each New Moon and Full Moon in any given year unique. This of course already makes for a complex calendar of seismic and volcanic activity. But wait we are just getting started!
Since the Earth's obital tilt pivots the Poles towards and away from the Sun each year, changing the angle about one degree a day, this means that the Moon's monthly tidal expansions and contractions will appear at different angles to the Earth's Northern and Southern Hemispheres. And accordingly, this means that the most potent expansions and contractions (produced by the Perigee Cycle) will show up in unique "anomalistic ways", insuring complete unique individuality to each Lunar Moment.
Since these Lunar Cycles precess in time against the Earth's annual orbit, this means that the timing of their combinations varies each year in relationship with the Earth's orbital cycles. They never occur on the same dates, not even in the same weeks or months.
Head swimming yet? It not, it will be shortly. We have one more layer in the cosmic mystery and it is the toughest one of all.
There is one more profoundly important cycle of fluctuation in the Moon's orbit. The Moon's orbit is tilted or inclined by about 5.145396 degrees, which is a fairly radical tilt, with respect to the Plane of the Ecliptic. The Ecliptic is the plane of Earth's orbit around the Sun. Actually the Ecliptic is the plane of the center of gravity of the combined Earth/Moon gravitational field. Such a "combined" gravity field is called a barycenter.
The points at which the Moon's orbit intersects the Earth's orbit (the plane of ecliptic) are called the Moon's "Nodes". The Moon crosses through these nodes during every orbital cycle but spends most of its time winging north of the Ecliptic or south of the Ecliptic. So, as seen from the center of the Earth, the Moon apparently drifts up and down slightly more than five degrees in the course of each orbit. But this is only as seen from the center of the Earth. On the surface of the Earth, which is spinning at an additional tilt of 23.5 degree, the Moon can be seen to travel much further to the North or South.
In more ancient days this was called the Dragon Cycle and astronomers still call this the "dagronic cycle of the Moon. The nodes are still called the Dragon's Nodes and the transit of the Moon to the north of the eclipse is referred to as the North Node or the Dragon's Head. The transit south of the eclipse is called the South Node or the Dragon's Tail. This is an interesting association because it connects directly to the ancient Chinese legends of the "dragon" force in the Earth which governs the flow of "earth energy" in the T'ai Chi "circuits" or "lines".
It also connects us with the ancient Egyptian legends of Apopis, the great snake which lives in the Earth which periodically rises to challenge the tree of life by inducing chaos. The Norse had an equivilent to Apopis. They called him Loki, the trickster, whose ultimate trick was to induce the Gotterdammerung, the end of the world by the hands of the Gods. This German word is most likely the origin of the Ennglish "Doomsday".
The dark grey wedge
shows the limits of the Moon's excursion above and below the plane
of the ecliptic.
up to 23.5 + 5.14 = 28.64 degrees, depending upon the synchronization of the orbital cycles.
What gives this cycle in the Moon such great potency is the wide expanse of territory the Moon is able to cover. The orbit is tilted 5.14 degrees to the plane of ecliptic but the Earth is also tilted to the plane of its own orbit by some 23.5 degrees. Sometimes these two orbital tilts "add" to make the Moon over 28.64 degrees north or south of the Equator, sometimes the tilts subtract to make the Moon no more than 18 degrees north or south. Most of the time, of course, the Moon is traversing between these various extremes. During any given month, the Moon may wing from Latitude North 18 or 28.64 to its opposite Latitude in the South.
The 18 degree swings are called Minor Lunastices, the 28.64 degree swings are called Major Lunastices. During each year, the Moon will go through a complete range of these swings in regularly recurring patterns or cycles. This is a huge variation and it is no doubt the source of much of the variations in the Earth's seismic and volcanic activity beneath it.
Perhaps the most revealing examples of this truth are the Great Quakes (7+) which tend to occur in greatest frequency on the Major Lunastices. Perhaps the most spectacular example was the Great Sumatra Rupture on December 25, 2004 which killed 90,000 people. This occurred almost dead on the Winder Solstice (when the Earth is in Perihelion at its closest approach to the Sun) on the same day that the exact Full Moon was almost in Perigee in the most extreme Major Lunastice possible of 28.64 degrees in the north above the equator opposite on the other side of the Earth from the Sun, which was at 23.5 degrees to the south below the equator.
We can call that a four star whammy: Perihelion, Perigee, Full Moon Expansion, Extreme Opposite Lunastice. The result was a complex strike-slip quake combined with a major subduction shift in the nearby ocean bottoms. It produced the most destructive, far-reaching tectonic event yet recorded!
The exceptional potency of this event was clearly connected with how the orbital planes of the Earth and the Moon intersect.
The Moon's orbital plane intersected at this particular time at a very sharp angle with the Earth's orbital plane which is of course called the plane of the ecliptic. This cycle of Lunar orbital swings is known as the eclipse cycle because all eclipses of the Sun or Moon occur at these orbital interactions when the phases of the Moon line up with the Nodes of the Moon.
This of course is also most popularly known as the 18 year Saros Cycle. The eclipses occur "at the Nodes", the Lunastices occur "at the extremes of the Moon above or below the equator, or in otherwords when the Moon is as far from the Sun as it can get.
Because of many minor factors in the motions of the Earth and Moon, the Moon is always slightly behind time in traveling to its Nodes. Thus the "Nodal Cycle" precesses independently of the Synodic New Moon Cycle and the Perigee Cycle, producing a "third beat" in the dance of the Wu Li Master. These synchronize and then fall out of connection in the regularly repeating cycle which is known as the Saros Cycle.
examine this on the chart
" Because of the variations of the shape
and tilt of the moon's orbit, about every 18.5 years, only then does
the moon move to its most extreme north and south motion, or "major
lunastice," of 28.64 degrees above and below the motion of the sun. And
that is the most dangerous time for the massive devastating
earthquakes and tidal waves.
Within the Saronic cycle sequences of eclipses repeat themselves, since the Sun, Moon and Earth return to almost the same relative positions. In consecutive cycles the later eclipse occurs at roughly the same latitude and for the same duration but about 8 hours later and 115° of longitude further west. The word is a Greek form of a Babylonian word shâr or shâru which may mean ‘universe’ or the number 3,600. Each saros contains about 43 solar and 28 lunar eclipses, and the slight element of difference in the bodies’ positions accumulates so that an eclipse cycle ends after a number of saroses, 71 saroses for solar and 48 for lunar eclipses
SAROS CYCLE - Background &Technical Information
Discussion about the Saros Cycle
Fred Espenak: "Eclipses and the Saros"; NASA: Planetary Transits Across the Sun; http://sunearth.gsfc.nasa.gov/eclipse/transit/transit.html
Past, Present, and Future Eclipses
a very long list from the ancient past to the far tuture.
(see also WordIQ’s site on the Eclipse Cycle.
Discussion On How The Saros Cycle Works
A Wonderfully Graphic Expostion of The Great Precesson and Lunar Cycles, Etc.
(see NASA’s site for more)
Solar System Dynamics On-line Tools
On-line tools designed to provide data in support of solar system body observations as well as general scientific research.
Time Date Conversion Tool:
Phases of the Moon: 2001 to 2025
Navy Observatory Ephemeris Generation
Naval Naval Observatory Ephemeris 2005-2008
The JPL HORIZONS On-Line Solar System Data and Ephemeris Computation Service provides access to key solar system data and flexible production of highly accurate ephemerides for solar system objects (planets, planetary satellites, comets, asteroids, the Sun, L1, L2, select spacecraft, and system barycenters). Access the HORIZONS web-interface using this link.
EPHEMERIS ONLINE AT
JPL/NASA: HORIZONS Web-Interface: