Crossing the Galactic Plane

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Crossing the Galactic Plane

Post by dougettinger » Tue Dec 14, 2010 2:46 pm

Supposely, the solar system travels in a sinusoidal path crossing and re-crossing the Milky Way's galactic plane. Are there any estimates made about how often the solar system crosses this imaginary plane ? Are there any estimates as to when our solar system will cross this plane the next time ? And I cannot even imagine how astrophysicists even know that this periodic crossing occurs (?)

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Tue Dec 14, 2010 7:20 pm

dougettinger wrote:Supposely, the solar system travels in a sinusoidal path crossing and re-crossing the Milky Way's galactic plane. Are there any estimates made about how often the solar system crosses this imaginary plane ?
A bit under three cycles per orbit, so maybe five plane crossings per orbit, or one every 50 million years.
Are there any estimates as to when our solar system will cross this plane the next time ?
We are close to the galactic plane now. And keep in mind, that there is no well defined plane, since the Milky Way is not perfectly symmetrical. There will be a period of a few million years during which we might be considered to be crossing the galactic "plane".
And I cannot even imagine how astrophysicists even know that this periodic crossing occurs (?)
Our position and velocity relative to the galaxy as a whole is observable. The rest is an application of Newtonian mechanics, from simple calculations ranging to complex n-body models.
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Re: Crossing the Galactic Plane

Post by dougettinger » Tue Dec 14, 2010 8:48 pm

I suppose that the center of the galaxy is determined in the sky. Then our changing position is measured from this fixed point with respect to background galaxies. Is my explanation fairly accurate? I am not sure how Newtonian mechanics can be applied to our motion in the galaxy precisely when Dark Matter is still a mystery.

Some "U-tube" presenter is exclaiming that the solar system crosses the galactic plane every 25,000 years. I pictured a sperm wiggling toward an egg. Did he get his information from any academic publication or is he just basing this number on something like a Mayan calendar prediction ?

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Wed Dec 15, 2010 12:08 am

dougettinger wrote:I suppose that the center of the galaxy is determined in the sky. Then our changing position is measured from this fixed point with respect to background galaxies. Is my explanation fairly accurate? I am not sure how Newtonian mechanics can be applied to our motion in the galaxy precisely when Dark Matter is still a mystery.
Our orbital parameters are estimated by looking at other stars in the Milky Way.

Dark matter isn't much of a mystery at all. Exactly what it is at the particle level is unknown, but for the Milky Way, its mass and distribution, and therefore its contribution to the orbital dynamics of the galaxy are pretty well known.
Some "U-tube" presenter is exclaiming that the solar system crosses the galactic plane every 25,000 years. I pictured a sperm wiggling toward an egg. Did he get his information from any academic publication or is he just basing this number on something like a Mayan calendar prediction ?
That's just wrong. The "plane" is so vaguely defined that we spend more time than that in the fuzzy region that roughly divides the galactic hemispheres.

The Earth precesses with a 26,000 year period. One result of this is that the plane of the ecliptic crosses the galactic plane (or more precisely, the galactic center lies on the ecliptic) once or maybe twice each precession cycle. Maybe that's what he's talking about?
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Re: Crossing the Galactic Plane

Post by dougettinger » Wed Dec 15, 2010 5:41 pm

I think you really mean the the Earth's equator aligns itself with the galactic plane twice each precession cycle. The plane of ecliptic of the planetary orbits should remain the same with respect to the galactic plane unless that also precesses.

Probably your are right. This U-tube presenter is referring to this event of the equator aligning itself with the galactic plane every 12,500 years and not 25,000 years. And the Earth's precession has nothing to do with crossing the galactic plane. His understanding and presentation of what is happening is entirely wrong.

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Wed Dec 15, 2010 5:57 pm

dougettinger wrote:I think you really mean the the Earth's equator aligns itself with the galactic plane twice each precession cycle. The plane of ecliptic of the planetary orbits should remain the same with respect to the galactic plane unless that also precesses.
Sorry, yes, I did mean the plane of the celestial equator. Note, however, that the plane of Earth's orbit (which defines the ecliptic) does indeed precess as well, with a 70,000 year period.
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Re: Crossing the Galactic Plane

Post by dougettinger » Wed Dec 15, 2010 7:08 pm

And the Earth's orbital plane with respect to the ecliptic also varies, I believe, cyclically every 100,000 years. I was just reading about Milankovitch Cycles.

Personally, I am not finding any clues about our demise in 2012.

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Wed Dec 15, 2010 7:44 pm

dougettinger wrote:And the Earth's orbital plane with respect to the ecliptic also varies, I believe, cyclically every 100,000 years. I was just reading about Milankovitch Cycles.
Yes, that's the same thing I referred to. Whether the period is 70,000 years or 100,000 years just depends on what you time it in reference to.
Personally, I am not finding any clues about our demise in 2012.
Well, since the idea is based on nothing scientific, and in fact represents a mistaken understanding of the Mayan calendar (as if the Mayan opinion on cosmology had any practical value), that's hardly surprising.
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Re: Crossing the Galactic Plane

Post by dougettinger » Wed Dec 15, 2010 8:47 pm

The Milankovitch Cycles deal with combining known celestial parameters that affect the major interglacial periods of this ice age. Those parameters are:
1) the tilt of the Earth, currently at 23 degrees, that varies cyclically a few degrees every 41,000 years;
2) the precession of the Earth every 26,000 years;
3) the apsidal precession of the Earth's eccentric orbit occuring every 21,000 to 25,000 years
4) the changing amount of eccentricity of the orbit both, (3) and (4) combining to produce cycles every 100,000 years and 400,000 years; and
5) the orbital inclination cycle that occurs every 100,000 years; the Earth's orbital plane passes through the dust disk of the solar system twice each cycle; the Earth presently passes through that disk every January and July resulting in increased meteor storms.

From well measured sea sediment cores it is determined that major interglacial periods occur every 100,000 years. These defined periods transitioned to 41,000 year periods between 1 and 3 million years ago. Possibly the Sun's emitted radiation energy changed and was a factor in earlier times.

I thought you would be interested in a summary of Earth's celestial parameters with respect to the Sun since we were previously discussing them. You definitely helped me with the concept that the Earth's equatorial plane does periodically align itself with the galactic plane via precession.

I edited some items: the apsidal precession cycle and how glaciation periods were measured.
Yes, I have mis-used some terms.

I edited a second ime to change the term glaciation periods.

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Wed Dec 15, 2010 8:56 pm

dougettinger wrote:From well measured glacier and sea sediment cores it is determined that major glaciation periods occur every 100,000 years. These defined periods faded away between 1 and 3 million years ago. Possibly the Sun's emitted radiation energy changed and was a factor in earlier times.
Don't confuse glacial ages with interglacial periods, however. We are currently in a glacial age, which began at least 3 million years ago. The glacial period previous to this one ended 260 million years ago. The 100,000 year pattern you are referring to describes interglacial periods during the current ice age (and possibly earlier ones). There are no glaciation periods at all between glacial ages, for example from 260 million years ago to about 3 million years ago.
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Re: Crossing the Galactic Plane

Post by dougettinger » Wed Dec 15, 2010 9:29 pm

I misused the terms glaciation age and interglacial periods. I presume the Milankovitch Cycles deal only with the interglacial periods of this Ice Age. I edited my last submission to fix some errors.

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Re: Crossing the Galactic Plane

Post by dougettinger » Thu Dec 16, 2010 3:15 pm

Chris Peterson wrote:
dougettinger wrote:I think you really mean the the Earth's equator aligns itself with the galactic plane twice each precession cycle. The plane of ecliptic of the planetary orbits should remain the same with respect to the galactic plane unless that also precesses.
Sorry, yes, I did mean the plane of the celestial equator. Note, however, that the plane of Earth's orbit (which defines the ecliptic) does indeed precess as well, with a 70,000 year period.
I am just trying to clean up my understanding of Earth's cycles. Where did you learn of this 70,000 year cycle?

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Thu Dec 16, 2010 3:25 pm

dougettinger wrote:I am just trying to clean up my understanding of Earth's cycles. Where did you learn of this 70,000 year cycle?
This is just the period of the precession of the ecliptic (also called the precession of the equator). It has a 70,000 year period relative to the current orbit of the Earth, and a 100,000 year period relative to the invariable plane. Which number you see just depends on the author. The 100,000 year value is more commonly used these days, because it involves Jupiter in the dynamics calculations and might help to explain the 100,000 year periodicity seen in the climate record.
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Re: Crossing the Galactic Plane

Post by neufer » Thu Dec 16, 2010 4:13 pm

Chris Peterson wrote:
This is just the period of the precession of the ecliptic (also called the precession of the equator). It has a 70,000 year period relative to the current orbit of the Earth, and a 100,000 year period relative to the invariable plane. Which number you see just depends on the author. The 100,000 year value is more commonly used these days, because it involves Jupiter in the dynamics calculations and might help to explain the 100,000 year periodicity seen in the climate record.
http://en.wikipedia.org/wiki/Precession wrote:
Axial precession (precession of the equinoxes/equator) : 26,000 years

<<Axial precession is the movement of the rotational axis of an astronomical body, whereby the axis slowly traces out a cone. In the case of the Earth, this type of precession is also known as the precession of the equinoxes or precession of the equator. The Earth goes through one such complete precessional cycle in a period of approximately 26,000 years, during which the positions of stars as measured in the equatorial coordinate system will slowly change; the change is actually due to the change of the coordinates. Over this cycle the Earth's north axial pole moves from where it is now, within 1° of Polaris, in a circle around the ecliptic pole, with an angular radius of about 23.5 degrees (or approximately 23 degrees 27 arcminutes). The shift is 1 degree in 72 years, where the angle is taken from the observer, not from the center of the circle.

Aristarchus of Samos (c. 280 BC) is the earliest known astronomer to recognize and assess the precession of the equinoxes at almost 1º per century (which is not far from the actual value for antiquity, 1.38º). The Precession (axial rotation) was later explained by Newtonian physics. Being an oblate spheroid, the Earth has a nonspherical shape, bulging outward at the equator. The gravitational tidal forces of the Moon and Sun apply torque as they attempt to pull the equatorial bulge into the plane of the ecliptic. The portion of the precession due to the combined action of the Sun and the Moon is called lunisolar precession.>>
http://en.wikipedia.org/wiki/Precession_of_the_ecliptic#Orbital_inclination wrote:
Planetary precession [nutation?] (precession of the ecliptic) : 70,000 years

<<The inclination of Earth's orbit drifts up and down relative to its present orbit with a cycle having a period of about 70,000 years. Milankovitch did not study this three-dimensional movement. This movement is known as "precession of the ecliptic" or "planetary precession".

More recent researchers noted this drift and that the orbit also moves relative to the orbits of the other planets. The invariable plane, the plane that represents the angular momentum of the solar system, is approximately the orbital plane of Jupiter. The inclination of the Earth's orbit has a 100,000 year cycle relative to the invariable plane; by chance, this is very similar to the 100,000 year eccentricity period. This 100,000-year cycle closely matches the 100,000-year pattern of ice ages.

It has been proposed that a disk of dust and other debris exists in the invariable plane, and this affects the Earth's climate through several possible means. The Earth presently moves through this plane around January 9 and July 9, when there is an increase in radar-detected meteors and meteor-related noctilucent clouds.

A study of the chronology of Antarctic ice cores using oxygen-nitrogen ratios in air bubbles trapped in the ice, which appear to respond directly to the local insolation, concluded that the climatic response documented in the ice cores was driven by northern hemisphere insolation as proposed by the Milankovitch hypothesis. This is an additional validation of the Milankovitch hypothesis by a relatively novel method, and is inconsistent with the "inclination" theory of the 100,000-year cycle.>>
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Re: Crossing the Galactic Plane

Post by dougettinger » Thu Dec 16, 2010 7:42 pm

Neufer, I had already read your submitted article, but somehow missed the reference to the 70,000 year cycle. However, re-reading the article brings two questions to mind.

Please tell me how a Greek astronomy in BC with his given instruments determined the Earth's axial precession to be one degree per year. How did he even know what it was that he was observing? Maybe an hands-on astronomer can explain it.
Maybe changes in human knowledge have some cycle of their own (?) Like, perhaps we have already been there and are learning everything we already once knew. I am waiting in great anticipation and suspense for Neufer's answer.

The above article mentions that the "inclination theory" is inconsistent with the other 100,000 year theories, but it does not explain. Is the reason that the eccentricity cycle and precession cycle are not closely synchronous ?

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Thu Dec 16, 2010 8:32 pm

dougettinger wrote:Please tell me how a Greek astronomy in BC with his given instruments determined the Earth's axial precession to be one degree per year.
At over 1° per century, axial precession has a significant effect on stellar position over relatively short periods. Any stable culture that paid attention to the stars (which was most) had the capacity to notice the motion in just a few generations. There are anecdotal reports of even earlier cultures being aware of precession (the Babylonians, the Egyptians), and given what we know of them, there's no reason they couldn't have been. Detecting precession requires nothing in the way of instrumentation. All you need is access to a few centuries of charts or descriptions of star positions to figure out that the sky is changing.
How did he even know what it was that he was observing?
He didn't know about precession as a physical principle, but the apparent change of position of the north celestial pole would make it clear enough to an intelligent observer what must be going on mechanically, even if he couldn't explain it.
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Re: Crossing the Galactic Plane

Post by dougettinger » Thu Dec 16, 2010 9:23 pm

Observing one degree per century is even harder to swallow. Observing star charts that positioned stars by at least fractions of a degree with respect to some fixed point and are one, two, or three centuries old. Did the Greeks or Romans really have that much stability and respect learned scholars and documents for several centuries? I don't believe that even our modern, digitized world has that capability.

I have a sky pointer that uses declination and right ascension to locate stars and planets. But it also needs time to complete its task. I do not believe the ancients had clocks to measure time to the required accuracy. And calendars also had to remain stable over several centuries. It must be true, but I have a hard time believing this without the help of some very intelligent civilization that disappeared prior to the Sumerians who eventually disseminatied knowledge to the Babylonians, Greeks, and Romans.

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Thu Dec 16, 2010 10:25 pm

dougettinger wrote:Observing one degree per century is even harder to swallow. Observing star charts that positioned stars by at least fractions of a degree with respect to some fixed point and are one, two, or three centuries old. Did the Greeks or Romans really have that much stability and respect learned scholars and documents for several centuries? I don't believe that even our modern, digitized world has that capability.
They did, and we do. Consider that the constellations have been known for thousands of years. The knowledge of what constellations are in a given part of the sky at a particular time of year has been known. But this changes with precession. Every astrologer knows today, and could have figured out thousands of years ago, that the position of the constellations was changing with time. It doesn't require any instruments at all, just a bit of folklore stable enough to survive centuries- which star patterns certainly are.

If your tradition tells you that the heliacal rising of some star occurs on the winter solstice, for instance, and you observe that it does not- well, you're going to figure the sky is changing, and you could even put a quantitative rate to that change.
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Re: Crossing the Galactic Plane

Post by dougettinger » Fri Dec 17, 2010 3:38 am

Astrologers use the zodiacal constellations to determine times of the year. I have not heard of their comparing the the plane of the zodiac with the plane of the galaxy. If we can believe the sky observers have communicated and tracked by fraction of degrees the movement of the constellations with respect to the solstices over thousands of years, then I might even start believing in the flood legends. Part of my disbelief probably stems from little experience with hands-on astronomy.

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Re: Crossing the Galactic Plane

Post by Chris Peterson » Fri Dec 17, 2010 4:29 am

dougettinger wrote:Astrologers use the zodiacal constellations to determine times of the year. I have not heard of their comparing the the plane of the zodiac with the plane of the galaxy. If we can believe the sky observers have communicated and tracked by fraction of degrees the movement of the constellations with respect to the solstices over thousands of years, then I might even start believing in the flood legends. Part of my disbelief probably stems from little experience with hands-on astronomy.
There is no suggestion that any ancient astronomers compared the plane of the zodiac with the plane of the galaxy. It is doubtful that they recognized either as planes. We are talking here about axial precession, where the Earth's rotation axis describes a circle on the sky with a period of 26,000 years. This results in a shift of the position of the celestial poles, and an overall change in what stars are in the sky at any given time of year. This was potentially detectable to ancient cultures without any instrumentation at all, although the Greeks are the first that we know with certainty recognized it.
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Re: Crossing the Galactic Plane

Post by dougettinger » Fri Dec 17, 2010 4:51 pm

For me it is hard to believe that one degree changes in the constellations every hundred years is transferred from generation to generation of astrologers/astronomers in BC times. Even today books over 100 years old are either collectors' items, most rapidly deteriorating, or they are preserved in museums with special atmospheres.

How was a polar star recognized in ancient times - unless you randonly picked a new star each clear night and watched for no motion? When you found the star with no motion you found the polar star for those times. Maybe this was the method for determining a fixed position in the sky without compasses and clocks. Indeed, stargazing had to be a big pastime in ancient times.

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Re: Crossing the Galactic Plane

Post by neufer » Fri Dec 17, 2010 5:32 pm

dougettinger wrote:
How was a polar star recognized in ancient times - unless you randonly picked a new star each clear night and watched for no motion? When you found the star with no motion you found the polar star for those times. Maybe this was the method for determining a fixed position in the sky without compasses and clocks. Indeed, stargazing had to be a big pastime in ancient times.
--------------------------------------------------------------------
http://users.iafrica.com/m/mi/mikeyb/Orion_Fairall.html wrote: <<Khufu's pyramid contains four 'star shafts', aimed towards
. the meridian in the sky. When the pyramid was built
. (c. 2700 BC), these shafts aimed at the transit points of:
.
  • . Thuban (Alpha Draconis - then pole star),
    . Orion's Belt,
    . Sirius and
    . KOCHAB (Beta Ursa Minoris - pole star in 1100 B.C.)
clearly intentionally and not coincidentally. The shafts apparently
served to direct the ka, or spirit, of the dead pharaoh towards these
key stars. Thuban and Kochab were circumpolar "Imperishable ones"
(stars that never die), Orion represented the deity Osiris, and
Sirius his consort, Isis. Precession has since changed the transit
points, so the shafts no longer function in this manner.>>
-----------------------------------------------------------------------
http://www.astro.uiuc.edu/~kaler/sow/kochab.html wrote: <<KOCHAB (Beta Ursa Minoris - pole star in 1100 B.C.), an obscure Arabic name that might simply mean "star," is just barely the second brightest, and appropriately the Beta, star in Ursa Minor, and represents the top front bowl star of the Little Dipper. Only 15 degrees from the north celestial pole, middle northerners can see it every night as it plies its small circular path. Together with the other bowl star (Pherkad, the Gamma star), it makes a small asterism called the "Guardians of the Pole," the two seeming in myth to "protect" the pole star. Though we are quite familiar with the major two motions of the Earth, daily rotation and annual revolution, the third motion, precession, is more obscure. The Moon and Sun act on the Earth's rotational bulge, and cause the axis to wobble over a 26,000 year period. The result is that the axis continually moves in a small circle against the background stars. Polaris is thus only a temporary pole star that will get better into the next century and then will begin to shift away. About the year 1100 BC, the pole made a reasonably close pass to Kochab, and there are old references to THIS star being called "Polaris.">>
----------------------------------------------------------------------
    • . Jules Verne: _Journey to the centre of the earth_
    Presently, after lying quietly for some minutes, I opened my eyes and looked upwards. As I did so I made out a brilliant little dot, at the extremity of this long, gigantic telescope. It was a star without SCINTILLATING rays. According to my calculation, it must be. Beta in the constellation of the Little Bear.
-----------------------------------------------------------------------
    • . James Joyce: _Ulysses_
    Meditations of evolution increasingly vaster: of the moon invisible in incipent lunation, approaching perigee: of the infinite lattiginous SCINTILLATING uncondensed milky way, discernible by daylight by an observer placed at the lower end of a cylindrical vertical shaft 5000 ft deep sunk from the surface towards the centre of the earth: of Sirius (alpha in Canis Major) 10 lightyears (57,000,000,000,000 miles) distant and in volume 900 times the dimension of our planet:
-----------------------------------------------------------------------
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Re: Crossing the Galactic Plane

Post by Chris Peterson » Fri Dec 17, 2010 5:56 pm

dougettinger wrote:For me it is hard to believe that one degree changes in the constellations every hundred years is transferred from generation to generation of astrologers/astronomers in BC times. Even today books over 100 years old are either collectors' items, most rapidly deteriorating, or they are preserved in museums with special atmospheres.
There's no need for charts, or written records at all. All you need is a cultural rule, such as the knowledge that the flooding of the Nile is heralded by the heliacal rising of Sirius. This ceased to be accurate while the Egyptians still had an active civilization, and is one reason that some archaeologists and historians believe the Egyptians knew of axial precession. Cultures that constructed buildings with stellar alignments could also have become aware of precession in just one or two centuries.
How was a polar star recognized in ancient times - unless you randonly picked a new star each clear night and watched for no motion? When you found the star with no motion you found the polar star for those times. Maybe this was the method for determining a fixed position in the sky without compasses and clocks. Indeed, stargazing had to be a big pastime in ancient times.
There hasn't always been a pole star. But I think it is safe to assume that many cultures developed methods of navigation that relied on star positions, and any of those would have been well aware that there's a place in the sky that doesn't change position with time on a daily scale. Any of those cultures lasting more than a few hundred years could have determined that precession was occurring based on nothing more than oral tradition.
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Re: Crossing the Galactic Plane

Post by dougettinger » Sat Dec 18, 2010 8:27 pm

So a realization certainly comes to mind with this discussion. The ancient peoples from perhaps 2000 BC to 500 AD had the tools to navigate larger bodies of water such as the Atlantic and Indian Oceans in the northern latitudes. Two books are remembered. The book, "1422", hypothesized that the Chinese of the Ming Dynasty circumnavigated the globe well before Columbus' time and supplied the maps to mariners looking for new routes from Europe to the Eastern Spice Islands. In another book, "The Lost Realms", it was postulated that the Bronze Age record shows a decline in the tin to copper ratio of bronze alloy. Then the ratio re-gained its optimum amount of tin supposely by sailors of the Mediterranean navigating the Atlantic, crossing the isthmus of Central America, sailing the western coast of South America, crossing the Andes to Bolivia and mining the much needed tin. This account supposely answers the origin of the Incas and the Toltecs and the unbelievable ancient structures found in central Bolivia.

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Re: Crossing the Galactic Plane

Post by dougettinger » Sat Dec 18, 2010 9:04 pm

neufer wrote:
dougettinger wrote:
How was a polar star recognized in ancient times - unless you randonly picked a new star each clear night and watched for no motion? When you found the star with no motion you found the polar star for those times. Maybe this was the method for determining a fixed position in the sky without compasses and clocks. Indeed, stargazing had to be a big pastime in ancient times.
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http://users.iafrica.com/m/mi/mikeyb/Orion_Fairall.html wrote: <<Khufu's pyramid contains four 'star shafts', aimed towards
. the meridian in the sky. When the pyramid was built
. (c. 2700 BC), these shafts aimed at the transit points of:
.
  • . Thuban (Alpha Draconis - then pole star),
    . Orion's Belt,
    . Sirius and
    . KOCHAB (Beta Ursa Minoris - pole star in 1100 B.C.)
clearly intentionally and not coincidentally. The shafts apparently
served to direct the ka, or spirit, of the dead pharaoh towards these
key stars. Thuban and Kochab were circumpolar "Imperishable ones"
(stars that never die), Orion represented the deity Osiris, and
Sirius his consort, Isis. Precession has since changed the transit
points, so the shafts no longer function in this manner.>>
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http://www.astro.uiuc.edu/~kaler/sow/kochab.html wrote: <<KOCHAB (Beta Ursa Minoris - pole star in 1100 B.C.), an obscure Arabic name that might simply mean "star," is just barely the second brightest, and appropriately the Beta, star in Ursa Minor, and represents the top front bowl star of the Little Dipper. Only 15 degrees from the north celestial pole, middle northerners can see it every night as it plies its small circular path. Together with the other bowl star (Pherkad, the Gamma star), it makes a small asterism called the "Guardians of the Pole," the two seeming in myth to "protect" the pole star. Though we are quite familiar with the major two motions of the Earth, daily rotation and annual revolution, the third motion, precession, is more obscure. The Moon and Sun act on the Earth's rotational bulge, and cause the axis to wobble over a 26,000 year period. The result is that the axis continually moves in a small circle against the background stars. Polaris is thus only a temporary pole star that will get better into the next century and then will begin to shift away. About the year 1100 BC, the pole made a reasonably close pass to Kochab, and there are old references to THIS star being called "Polaris.">>


Neufer, I have a thought provoking question. If Khufu's people knew about precession why would they build a very permanent structure for recording the star posiitons for one moment of time? You are telling me that the "ka spirit" or the King's soul required a way to find its way home. Thusly, all other souls are eternally lost. The good news is that some souls have permission to wander and explore per Starship Asterisk.

Thanks for showing me the graphics of the wandering pole star. Visualization is a tremendous aid for me.

Doug Ettinger
Pittsburgh, PA
Doug Ettinger
Pittsburgh, PA

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