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Monday, August 2, 2010

Big Bang? A Critical Review

Journal of Cosmology, 2010, Vol 6, 1533-1547.
Cosmology, January 30, 2010


Big Bang? A Critical Review Ashwini Kumar Lal, Ph.D.
Deputy Adviser, Ministry of Statistics & Progrmme Implementation New Delhi, India

Abstract
Inflationary Big Bang model is the generally accepted theory for the origin of universe. Nonetheless, findings in observational astronomy and revelations in the field of fundamental physics over the past two decades question the validity of the 'Big Bang' model as a viable theory for the origin of the universe. This paper examines a few of the various factors which undermine the theory of the Big Bang, including the organization of galactic superstructures, the Cosmic Microwave Background, distant galaxies, gravitational waves, red shifts, and the age of local galaxies.
Keywords: Big Bang, Redshift, Cosmic Background Radiation, Concordance Model, WMAP, Superclusters, Sloan Digital Survey , Gravitational - wave Background






1. Introduction.
Most, but not all cosmologists favor the inflationary Big Bang model as a viable explanation for the origin and nature of the universe. The origin of the Big Bang, that is, the state of "existence" which resulted in a Big Bang, is a mathematically obscure state - a "singularity" of zero volume that contained infinite density and infinite energy. Why this singularity existed, how it originated, and why it exploded, cannot be explained, and this state of affairs has led many scientists to question and challenge the validity of the Big Bang theory (Arp et al. 2004; Eastman 2010; Lerner 1991; Ratcliffe, 2010; Van Flandern 2002).
There is considerable evidence which has been interpreted as supporting a Big Bang origin of the universe, i.e. expansion and acceleration (Perlmutter et al., 1998; Schmidt et al., 1998). However, it has also been pointed out that an accelerated expansion limited to the most distant regions of the known universe, is incompatible with an explosive origin, but instead is indicative of an attractive force, i.e. a "universe-in-mass" black hole whose super-gravity is effecting red shifts and illumination, creating the illusion of a universe which is accelerating as it speeds away, when instead the stars closest to the hole are speeding faster toward their doom (Joseph 2010a). Other scientists have also pointed out that the interpretation of red shifts as supporting a Big Bang, is also flawed and lacking validity (Arp et al., 2004; Lerner 1991; Ratcliffe 2010; Van Flandern 2002). In fact, there is little evidence to support the belief that red shifts are accurate measures of distance or time (Arp et al., 2004; Ratcliffe 2010) and they are so variable and effected by so many factors that estimates of age, time, and distance can vary by up to 3 billion years following repeated measurements, over the just a few years, of the same star (Joseph 2010a).
There are also many opinions about the meaning of the isotropic cosmic microwave background radiation (CMB), believed to be relic of the Big Bang permeating the Universe. The CMB was first detected by Penzias and Wilson in a chance discovery in 1965, and subsequently confirmed by NASA's Cosmic Background Explorer (COBE) in 1991 and the Wilkinson Microwave Anisotropy Probe (WMAP) in 2003 (Benett et al. 2003). Many scientists believed that the CMB weigh heavily in favor of the Big Bang model of the origin of the universe (Figs. 1 & 2). This discovery, and the interpretations of its meaning, in fact, convinced many who supported an an infinite or "steady state" universe, that the Big Bang model was the correct one. Not all are convinced, however, and many have expressed their doubts (Arp et al. 1990; Lal 2008; Lerner 1991; Ratcliffe 2010; Van Flandern 2002).


Figures 1 & 2: Comparison of the predictions of the standard Big Bang model with experimental measurements. The power spectrum of the cosmic microwave background radiation anisotropy is plotted in terms of the angular scale (or multipole moment) (top) Credit : NASA/WMAP Science Team The observed abundances of hydrogen, helium, and other lighter elements such as deuterium, and lithium - believed to have been generated during the process of nucleosynthesis in the immediate aftermath of the Big Bang also apparently lends credence to the Big Bang model (Fig. 3). On the other hand, it has been pointed out that the heat generated by a Big Bang would have been so intense that all these elements would have been turned into iron and would have resulted in a universe made of heavy metal (Joseph 2010a). Instead, it has been argued that the simplest of gases and atoms, beginning with hydrogen, can be explained by the activity of "black holes" from those smaller than a Plank length in size, to supermassive black holes within the heart of quasars (Joseph 2010a,b).


Figure 3: Relative abundances of lighter elements (curves indicate the theoretical predictions from Big Bang nucleosynthesis, the horizontal stripes the values that follow from observations) Adapted from an image by E. Vangioni, Institut d'Astrophysique de Paris Van Flandern (2002), former Chief Astronomer for the United States Naval Observatory, has detailed 30 major problems with the Big Bang theory, including its reliance on ad hoc theorizing to paper over glaring inconsistencies, its reliance on constantly adjustable parameters to prevent its falsification, and the fact that there are quasars, large scale structures, and gobular clusters which are far older than the date given for the Big Bang.

Although the "Big Bang" is often presented as if it is proven fact, there is a wealth of data, including recent revelations of the several space probes and findings in fundamental physics, which tells a different story (Arp et al. 1990, 2004; Eastman, 2010; Lal 2008; Lerner 1991; Ratcliffe 2010; Van Flandern (2002).
2. Large - Scale Structures in the Universe.
In recent years, there have been a number of very serious challenges to the current theory of cosmic evolution and the belief the universe began just 13.7 billion years ago. These include the observation of large chains of galaxies spread throughout the universe forming gargantuan stellar structures separated by vast voids. The system of galactic superclusters forms a network permeating throughout the space, on which about 90% of the galaxies are located.
The existence of these "Superclusters", "Great Walls" and "Great Attractors" could have only come to be organized and situated in their present locations and to have achieved their current size, in a universe which is at least 80 billion to 250 billion years in age. The largest superclusters. e.g., "Coma", extend up to 100 Mpc!
In 1986, Brent Tully of the University of Hawaii reported detecting superclusters of galaxies 300 million light years (mly) long and 100 mly thick - stretching out about 300 mly across. At the speeds at which galaxies are supposed to be moving, it would require 80 billlion years to create such a huge complex of galaxies (Tully 1986).
In 1989, a group lead by John Huchra and Margaret J. Geller at the Harvard-Smithsonian Center for Astrophysics discovered "The Great Wall"- a series of galaxies, lined up and creating a "wall" of galaxies 500 million light years (mly) long, 200 mly wide, and 15 mly thick. This superstructure would have required at least 100 billion years to form.
A team of the British, American, and Hungarian astronomers have reported even larger structures. As per their findings, the universe is crossed by at least 13 'Great Walls', apparent rivers of galaxies 100Mpc long in the surveyed domain of 7 billion light years. They found galaxies clustered into bands spaced about 600 millon light years apart. The pattern of these clusters stretches across about one-fourth of the diameter of the universe, or about seven billion light years. This huge shell and void pattern would have required nearly 150 billion years to form, based on their speed of movement, if produced by the standard Big Bang cosmology (Lerner 1990).


Figure 4: SDSS 3D Universe Map Credit: Sloan Digital Sky Survey Team, NASA, NSF, DOE.
The "Sloan Great Wall" of galaxies, as detected by the Sloan Digital Survey (Fig. 4), has earned the distinction of being the largest observed structure in the Universe (Richard et al. 2005). It is 1.36 billion light years long and 80% longer than the Great Wall discovered by Geller and Huchra. It runs roughly from the head of Hydra to the feet of Virgo. It would have taken at least 250 billion years to form, if produced following a "Big Bang" creation event.
As summarized by Van Flandern (2002), "The average speed of galaxies through space is a well-measured quantity. At those speeds, galaxies would require roughly the age of the universe to assemble into the largest structures (superclusters and walls) we see in space, and to clear all the voids between galaxy walls. But this assumes that the initial directions of motion are special, e.g., directed away from the centers of voids. To get around this problem, one must propose that galaxy speeds were initially much higher and have slowed due to some sort of "viscosity" of space. To form these structures by building up the needed motions through gravitational acceleration alone would take in excess of 100 billion years."

Then there is the problem of gravity. "Hubble length" Universe, which consists of those galaxies and stars which can be observed by current technology, appears, therefore, to be organized as titanic walls and clusters of galaxies separated by a collection of giant bubble-like voids. The Great Walls are far too large and massive to have been formed by the mutual gravitational attraction of its member galaxies alone.
Discovery of the Great Walls of galaxies and filamentary clumping of galactic mater has greatly upset the traditional notion that galactic matter should be uniformly distributed. If the universe began with a Big Bang 13.7 billion years ago, the awesome size of these large-scale structures is baffling because there is apparently not sufficient time available for such massive objects to form and to become organized.
Based on the cosmological principle, which is one of the cornerstones of the Big Bang model, cosmologists predicted the distribution of matter to be homogeneous throughout the universe, implying thereby that the distribution of the galaxies would be essentially uniform. There would be no large scale clusters of galaxies or great voids in space. Instead, contrary to the "Big Bang" universe, we exist in a very "lumpy" cosmos.
3. Age of Universe
Based on the findings of the WMAP, astronomers at NASA's Goddard Space Flight Center proclaimed the age of Universe as 13.7 billion years (Benett et al. 2003). They claim that the WMAP data along with the complementary observations from other CMB experiments like CBI (Cosmic Background Imager) and DASI (Degree Angular Scale Interferometer) confirm the inflationary Big Bang model of the Universe (Figs. 1 and 2).
However, these claims are based on interpretations of data which are guided by the belief that there is no alternative explanation. Hence, rather than the data shaping the theory, the theory of the "Big Bang" dictates how data are interpreted and even which data should be included vs ignored. For example, it has been claimed that temperature fluctuations in the CMB are as little as one-millionth of a degree, and these are caused by variations in the density of the infant Universe at an epoch 380,000 years after the Big Bang, after which the universe rapidly cooled. However, it has also been asked: "What happened to the heat?" If everything was contained in a super-hot expanding universe which originated as a singularity, then there could be no "cold sink" or thus no cooling due to conduction or convection and temperature disequilibrium (Joseph 2009).
Supposedly, the universe rapidly cooled when radiation first decoupled from matter, creating vast hot and cold spots. Differences in temperature and matter creation supposedly led to clumping and eventually the formation of galaxies, stars and planets.
However, recent research studies undertaken by the scientists at CERN and Case Western University in the US have questioned the authenticity of the WMAP interpretations (Schwarz et al. 2004). Although most cosmologists think that the tiny variations in the temperature of the CMB are related to quantum fluctuations in the early Universe, Starkmen and Schwarz (2005) have reported that some of these variations are due to processes occurring in our solar system. According to their findings, the tiny temperature variations (0.00003ºC) detected have a strong statistical connection with the solar system, and has nothing to do with a Big Bang.
In fact, the claim for uniformity in the CMB, is just not true. Instead of variations which are as little as one-millionth of a degree, there are regions of space, vast voids, where the temperature of the CMB fluctuates significantly from surrounding space (Rudnick et al., 2007). For example, a black hole (Joseph 2010a) or void, over a billion light-years across, in the constellation of Eridanus, has apparently swallowed up all galaxies, gas, and light, including radiation from the CMB (Rudnick et al., 2007) . Based on an analysis of the NRAO VLA sky Survey (NVSS) data, Rudnick et al. (2007) discovered that there was a significant absence of galaxies in the constellation of Eridnus and which was also sucking in thermal energy and even consuming the cold from the CMB which is dragged inside. Joseph (2010a) argues for the presence of a "black hole" that he estimates must have gravity-mass of thousands of entire galaxies, such that even the energy of the CMB can be captured as the temperature of the hole is lower than the CMB. Holes of all size permeate the universe, according to Joseph (2010). If correct, then the overall temperature of the CMB and its fluctuations would have nothing to do with a Big Bang, but would be due to holes in space time which consume matter, gravity, energy, and some of which emit thermal energy in the process (Joseph 2010ab).
Van Flandern (2002) also notes that the "Big Bang offers no explanation for the kind of intensity variations with wavelength seen in radio galaxies" which he believes must be a function of absorption by unknown stellar material within deep space: "The amount of radiation emitted by distant galaxies falls with increasing wavelengths, as expected if the longer wavelengths are scattered by the intergalactic medium. For example, the brightness ratio of radio galaxies at infrared and radio wavelengths changes with distance in a way which implies absorption. Basically, this means that the longer wavelengths are more easily absorbed by material between the galaxies. But then the microwave radiation (between the two wavelengths) should be absorbed by that medium too, and has no chance to reach us from such great distances, or to remain perfectly uniform while doing so. It must instead result from the radiation of microwaves from the intergalactic medium. This argument alone implies that the microwaves could not be coming directly to us from a distance beyond all the galaxies, and therefore that the Big Bang theory cannot be correct."
In addition, the WMAP, which supports the "concordance (Λ-CDM) model" of the Universe with up to 73% dark energy, 23% dark matter and bare 4% comprising all the matter in observable universe, has been under attack in recent years. Critics have complained that claims for the existence of invisible, unknown forces, to support a theory where it is admitted that over 90% of the universe it seeks to explain cannot even be detected, hardly seems worthy of being called "science."
Surveys of distant cluster of galaxies undertaken by an international group of astronomers, European Space Agency's XMM-Newton satellite observatory has also cast doubt on the existence of dark energy itself (Vauclair et al. 2003). Moreover, it was found that clusters of galaxies in the distant universe were not found to be similar to those located closer to Earth. They seem to release more x-rays. These findings also indicate that the universe must be a high-density environment which is a clear contradiction to the popular "concordance model."
4. Early Galaxies.
Combining Advanced camera for Survey (ACS) and the Infrared Camera for Multi-object Spectrometer (NICMOS), the Hubble Ultra Deep Field (HUDF) has revealed the presence of estimated 10,000 fully formed galaxies in a patch of sky in the constellation, Formax - a region just below the constellation, Orion (NASA News Release 2005). According to the NASA interpretation, these fully formed galaxies emerged just 700 million years after the Big Bang, when the universe was barely 5% of its current age (z ~ 7).
Also, using ISAAC near- infrared instrument aboard ESO's Very Large Telescope(VLT), and the phenomenon of gravitational lensing, a team of French and Swiss astronomers using Very Large Telescope (VLT) of the European Southern Observatory, have identified an extremely faint galaxy, Abell 1835 IRI 1916 at z=10 (Pello et al., 2004).
According to their interpretations (Pello et al., 2004) Abell 1835 must have formed just 460 million years after the universe was born, during the "Dark Age" when the first stars and galaxies were supposedly being born More recently, fully formed galaxies were discovered which are at a greater distance, over 13.1 billion light years (American Astronomical Society 2010), and which must have already been billions of years in age, over 13 billion years ago (Joseph 2010a).
However, there are many problems with these interpretations. First and foremost, they are based on an Earth-centered universe (Joseph 2010a); all estimates of time are based on how distant these galaxies are from Earth. As Earth is not "ground zero" for the Big Bang, then distance from Earth have nothing to do with the age of these galaxies (Joseph 2010a). Second, the claims that these are "primitive" galaxies are based on light waves which could be interpreted to suggest they are metal poor. Metal poor, it is claimed, indicates a young, primitive galaxy. However, our own Milky Way galaxy is orbited by two very old metal poor dwarf galaxies, Sagittarius Dwarf Elliptical Galaxy and the Canis Major Dwarf Galaxy (Chou, et al., 2009; Ibata et al., 1997; Majewski et al., 2003; Martin et al., 2004) whereas the Milky Way is believed to be 13.6 billion years in age (Pasquini et al., 2005). Metal poor is not an indication of "primitiveness" or youthfulness as fully formed ancient galaxies near our Milky Way are also metal poor (Van Flandern 2002). In fact, lots of metal has been detected in distant quasars and galaxies (Van Flandern 2002), and if distance is related to age, this means that many of the oldest, most distant galaxies are metal rich; and this defies the predictions of the Big Bang.
Therefore, there are fully formed distant galaxies that must have already been billions of years old over 13 billion years ago; which would make them older than the Big Bang. Then there is the problem of the oldest globular clusters so far discovered, whose ages are in excess of 16 billion years (Van Flandern 2002). The Milky Way and other galaxies are also so old that they must have formed before the so called "Dark Ages" and thus almost immediately after the Big Bang, which is not consistent with theory.
Also, images taken with the Hubble Space Telescope and other larger telescopes show that no two galaxies are alike, and the endless varieties of galactic forms pose grave challenges to the theory governing evolution of the diverse galactic shapes.
Using the Infrared Array Camera (IRAC) aboard NASA's Spitzer Space Telescope, astronomers have detected about a dozen very red galaxies at a distance of 10 to12 billion light years from Earth (cfa Harvard 2005). According to the Big Bang model, these galaxies existed when the universe was only about 1/5 of its present age of 13.75 billion years. The unpredicted existence of "red and dead" galaxies so early in the universe challenges Big Bang theories relating to galaxy formation (cfa Harvard 2005). Analysis showed that galaxies exhibit a large range of properties. Young galaxies with and without lots of dust, and old galaxies with and without dust. There is as much variety in the so called "early universe" as we see around "today" in galaxies closer to Earth.
Moreover, Spitzer Space Telescope, which is sensitive to the light from older and redder stars, has also revealed evidence for mature stars in less massive galaxies at similar distances (Spitzer 2005), when the Universe was supposedly less than one billion years old.
5. Gravitational Wave Background.
One of the acid tests relating to the validity of the Big Bang model is detection of remnant of gravity waves from the earliest epoch of the universe. Existence of gravitational wave background, as predicted by Einstein in 1916 in his general theory of relativity, is expected from the violent early moments of the Big Bang much like the cosmic microwave background that fills the sky with radio waves from the early universe. While the microwave background presumably originated 380,000 years after the Big Bang, gravitational wave background purportedly come directly from events in the first minute after the Big Bang. The cataclysmic Big Bang is believed to have created a flood of gravitational waves; ripples in the fabric of space-time. These gravitational waves should still fill the universe. However, presumably they are at a very feeble strength and cannot be detected by conventional astronomical tools. Nevertheless, they should carry information about the universe as it was in the immediate aftermath of the Big Bang. If these waves cannot be detected, this challenges the Big Bang.


Figure 5: Schematic diagram of Laser Interferometer Gravitational-wave Observatory Credit : http://space.mit.edu/LIGO/more.html These waves should be observed as the "stochastic (random) background" – analogous to a superposition of many waves of different size and directions on the surface of a pond. The amplitude of the background is directly related to the parameters that govern the behaviour of the universe during the first minute after the Big Bang. The primordial stochastic gravitational waves are the warps, twists, and bends in space-time that were supposedly laid down as universe expanded from its earliest moments to the present.
The LIGO (Laser Interferometer and Gravitational Wave Observatory - jointly managed by MIT and Caltech, USA) and GEO 600 (the German-UK interferometer detector) have been actively searching for the gravity waves since 2002. The Italian Virgo interferometer joined the search in 2007. As per a a recent report (LIGO et al. 2009)stochastic background of the gravitational waves, expected as unique signature from the earliest moment of evolution of the universe, has not been discovered despite 2 years of sustained search for gravity waves. No gravitational waves contradicts the Big Bang theory.
6. Rivers of Galaxies Flowing in the Wrong Direction
The Big Bang predicts general uniformity in the trajectory of galaxies, and yet, contrary to this theory (Joseph 2010a) there are galaxies crashing into each other from every conceivable direction. There are in fact rivers of galaxies flowing in the wrong direction, including local galaxies who streaming motions are too high for a finite universe that is supposed to be everywhere uniform (Van Flandern 2002).
As summarized by Van Flandern (2002): "The average redshift for galaxies of a given brightness differs on opposite sides of the sky. The Big Bang interprets this as the existence of a puzzling group flow of galaxies relative to the microwave radiation on scales of at least 130 Mpc. Earlier, the existence of this flow led to the hypothesis of a "Great Attractor" pulling all these galaxies in its direction. But in newer studies, no backside infall was found on the other side of the hypothetical feature. Instead, there is streaming on both sides of us out to 60-70 Mpc in a consistent direction relative to the microwave "background". The only Big Bang alternative to the apparent result of large-scale streaming of galaxies is that the microwave radiation is in motion relative to us", a result which is contrary to the theory of the Big Bang.
Moreover, at the center of the local supercluster, 250 mly away in the direction of the Hydra and Centaurus constellations, rivers of galaxies over a region of hundreds of million light years across, are all flowing in the same direction; an "anomaly," which defies Big Bang predictions, and is thus attributed to a "Great Attractor" the identify of which is unknown.
7. Constancy of Speed of Light.
One of the basic assumptions of Einstein's general theory of relativity, is the constancy of the speed of light. A varying speed of light contradicts Einstein's theory of relativity, and conflicts with the Big Bang model for the universe. In recent years, the speed of light has been observed to have exceeded the speed of 300,000 km/sec, albeit over short range, in quantum tunneling experiments (Landauer 1993, Brown 1995). This has led some to claim that light moved faster during the early stages of the universe. For example, the evidence for variations in the fine-structure constant, α (= e2/ ħc) - a measurement of the strength of electromagnetic interaction between photons and electrons based on measurement of light travelling billions of years from quasars (Davies, et al 2002) has been used to claim that the speed of light was faster than its current speed some 6 to 10 billion years ago. The fine-structure is believed to be slowly increasing over cosmic timescales. These explanations have been offered up in order to explain away some of the major holes in Big Bang theory.
The laws governing the physical world cannot afford to be selective in their attributes, simply for the sake of saving a theory.
8. Oldest Planet.
In July 2003, the oldest planet yet was discovered, a huge gaseous object equivalent to 2.5 times the size of Jupiter whose origin dates back to about 13 billion years (at z ~7). This ancient planet was located by the Hubble Space the Telescope near the core of the ancient globular cluster M - 4 located some 7,200 light years away in the northern - summer constellation of Scorpius (Hansen et al. 2003). This discovery challenged a widely held view among astrophysicists that planets could not have originated so early because the Universe had yet to generate heavy elements needed to make them.
Planet-making ingredients include iron, silicon and other elements heavier than helium and hydrogen. These so-called metallic elements are cooked in the nuclear furnaces of stars, and accumulate from the ashes of dying stars (supernovae), which are recycled in new stars and their families of planets (Joseph and Schild 2010).
Planets 13 billion years in age, nearby galaxies 13.6 billion years in age, distant galaxies billions of years older than the supposed Big Bang, and the existence of Great Galactic Walls that took from 80 billion to 250 billion years to form, do not support the Big Bang theory.
9. Future Probes.
We are presently in a "golden age" of cosmological discoveries. Astronomers working on the WMAP mission stunned the scientific community with their announcement that the first generation stars in the universe were surprisingly born just after 200 million years of the Big Bang birth of the cosmos. Of course, the fact is, the true age of the universe is unknown, and since its inception, the age of the universe has been steadily pushed backwards in time, from 2 billion year to 8 billion after it was determined the Earth was 4.6 billion years in age, and now the estimates are 13.75 billion years.
With ten times the light-gathering power of Hubble, the James Webb Space Telescope (JWST), successor to the HST due to be launched in 2014, may well detect ever more distant galaxies. Likewise, the ultra-high resolution radio telescopes such as Atacama Large Millimeter Array (ALMA) in Chile which is to become operational in 2012, will be peering still deeper into the universe, and probably pushing the hypothetical Big Bang further backward in time as ever more distant galaxies are detected.
10. Conclusion.
There is a growing body of evidence which demonstrates the Universe could not have begun with a Big Bang 13.75 billion years ago. Indeed, the day may come when it is determined there never was a "Big Bang" and cosmologists of the future will only gaze back in wonder at how anyone could have believed in a creation event which was refuted by so much contradictory evidence.

Ancient Greek-Roman Cosmology


Journal of Cosmology, 2010, Vol 9, IN PRESS
JournalofCosmology.com, July, 2010

Ancient Greek-Roman Cosmology:
Infinite, Eternal, Finite, Cyclic, and Multiple Universes
Helge Kragh, Ph.D.,
Department of Science Studies, Building 1110, University of Aarhus, 8000 Aarhus, Denmark.

Abstract
Ancient Greek cosmologists were not of one mind and did not generally embrace Aristotle’s cosmology, in spite of the unrivalled long-term importance of his theories during the Middle Ages. Every one of its basic tenets – eternity, changelessness, spatial finitude, uniqueness and the separation in a sublunar and superlunar region – was at some stage questioned by Greek philosophers either before or after Aristotle. Among the alternative cosmologies that are worth reconsidering are the cyclic models proposed by Stoic thinkers and the finite-age, infinite-space ideas favoured by some authors of the atomistic school. These alternative cosmologies are not only of interest in their own right, but also because they include elements that turned up in much later scientific theories of the universe, including steady state, multiple worlds, cyclic, "big crunch" and recent conceptions of an infinite recycling universe.
Keywords: Ancient cosmology, ekpyrosis, Aristotle, Stoic cosmology, eternity, Lucretius, Epicurus , Lucretius, Empedocles, Atomists.



1. Aristotles’ Cosmos
Aristotles’ view of the universe is a natural focal point for discussions of ancient cosmologies, whether these belong chronologically before or after Aristotle. (To speak of non-Aristotelian cosmology before Aristotle is of course anachronistic, but it nonetheless makes good sense.) The long-term significance of Aristotle’s picture of the universe can hardly be overrated, not least because the major part of it became integrated in the natural philosophy of the middle ages, where it obtained a nearly doctrinal status. In fact, in Greek antiquity Aristotelian cosmology held considerably less authority that in did in the medieval and renaissance eras. At any rate, no account of Greek-Roman cosmology can avoid relating to the issues discussed so influentially by Aristotle. The books of relevance for cosmology are principally On the Heavens and parts of Physics, and secondarily Meteorology, On Generation and Corruption, and book 12 of Metaphysics (Barnes 1984). A further work, known as On the Universe, is relevant as well, but it is generally believed to be pseudo-Aristotelian, that is, written by a later author. Aristotle’s main works are often known by their Latin titles, in this case De Caelo, Physica, De Meteorologica, De Generatione et Corruptione, Metaphysica Lambda, and De Mundo.
So, what were the defining features of the Aristotelian universe? Briefly put, it can be described as a two-region universe in a steady state. According to Aristotle, the universe at large consisted of two essentially different realms, the sublunar and the superlunar world. The first region, covering the Earth and the air up to the Moon, was composed of bodies made up of the four terrestrial elements with their rectilinear motions, either towards the centre of the Earth (earth, water) or away from it (air, fire). Beyond the Moon, the bodies moved naturally in eternal, uniform circular motions. The stars, planets and celestial spheres were composed of an entirely different kind of matter, an ethereal semi - divine substance or fifth element, what Aristotle called the aither but is better known by the later Latin name quinta essentia. The aither resided exclusively above the Moon and its natural motion was, contrary to that of the terrestrial elements, circular. In the Meteorology Aristotle said that the purity of the aither increased in proportion to its distance from the sublunar world. Whether in the sublunar or superlunar region, a void could not possibly exist, and hence the universe was a plenum.
Aristotle’s cosmos was in a steady state in so far that it was eternal and local changes were restricted to the sublunar world. He argued that the universe as a whole was ungenerated as well as indestructible. Among several arguments against cosmic creation, Aristotle referred to what is known as the ‚why not sooner?' argument: If the universe came into being a finite time ago, what reason could there possibly be for just this time rather than some other time? He also denied that the universe (or any other body) could be created out of nothing, because that would require a pre-existing void, which he considered an impossible notion. A spatially infinite world was another impossibility, for by its very nature the world – meaning the heavens – revolved in a circle, and Aristotle pointed out that such motion was impossible as it would lead to an infinite velocity. What was enclosed by the outermost sphere comprised everything. In summary, Aristotle maintained that the universe was unique, eternal, and all inclusive:

The world as a whole includes all of its appropriate matter... So that neither are there now, nor have there ever been, nor can there ever be formed more heavens than one, but this heaven is one and unique and complete. It is therefore evident that there is also no place or void or time outside the heaven. For in every place body can be present; and void is said to be that in which the presence of body, though not actual, is possible; and time is the number of movement. But in the absence of natural body there is no movement, and outside the heaven < body neither exists nor can come to exist. (Barnes 1984, Vol. 1, p. 462) It was this conception of the universe that was incorporated into the medieval world view, except for the controversial and most un-Christian claim of the universe being past eternal.
2. Cyclic Conceptions
Ideas of cosmic cycles were well known in ancient Greece, both before and after Aristotle. Empedocles from Acragas in Sicily famously postulated four basic elements (earth, air, water, fire) which permanently kept their character and the arrangements and rearrangements of which accounted for what appeared to be generation and destruction in nature. He described the cosmos as a self-contained sphere passing through cycles of rest and change, with recurring stages of conflict which produced forms of life. In a characteristic vitalistic terminology Empedocles called the polar opposing forces or principles for philia ('Love') and neikos ('Strife'). The changes between dominance by Love and Strife proceeded eternally, corresponding to continual creations and destructions of the world. However, the two forces were not simply creative and destructive, for the conditions of life demanded a certain balance between them. When Love dominated, the elements were mixed up into a uniform mass, while at the time of Strife’s complete dominance they were fully separated from one another and arranged in concentric spheres. Only in between the two extremes was the universe hospitable to processes generating life.
Empedocles’ cycles were symmetric, so that the events in one phase were repeated in the opposite phase, but in reverse time order. Thus a process from birth to death would be followed by one from death to birth. Without requiring an identical repetition, Empedocles posited a cosmos without beginning or end. In one of his enigmatic fragments he speaks of a 'double birth' and a 'double passing away,' for 'the unity of all things brings one generation into being and destroys it, and the other is reared and scattered as they [the elements] are again being divided' (Wright 1995, p. 142; O’Brien 1969). The periods of the cosmic cycles were said to be very long, but Empedocles did not specify their length.
The later Stoic philosophers adopted the idea of temporally multiple universes, which they associated with thermal phenomena. What Empedocles poetically had named Love and Strife was now conceived more naturalistically or mechanically, namely as condensation and rarefaction. In what has been called "a first tentative approach to the conception of thermodynamic processes in the inorganic world" the Stoics assigned a dynamic role to fire in all areas of natural phenomena, indeed to the cosmos itself (Sambursky 1959, 1963, p. 133). Fire was the agent that caused change and decay in the universe, eventually to lead to its conflagration – evidently a most un- Aristotelian notion. However, the conflagration would not be the absolute end of the universe, for it was thought to be reborn and from the primeval fire to return identically to its former state. In a lost book known as On the Cosmos, Chrysippus from Cicilia is to have said that "after the conflagration of the cosmos everything will again come to be in numerical order, until every specific quality too will return to its original state, just as it was before and came to be in that cosmos" (Sambursky 1963, p. 202).
Assuming the physical world to be placed in an infinite non-physical void, the Stoics conceived the cosmos as a gigantic sphere oscillating through cycles of expansion and contraction in the void surrounding it. The agent responsible for the cyclic changes was ultimately the fire element. According to a Stoic source, "the material world preserves itself by an immense force, alternately contracting and expanding into a void following its physical transmutations, at one time consumed by fire, at another beginning again the creation of the cosmos" (Sambursky 1963, p. 203). For the idea of cosmic conflagration Zeno of Citium and later Stoic philosophers used the term ekpyrosis, meaning 'out of fire.' According to Plutarch, "When ekpyrosis takes place, [Chrysippus] says that the universe is totally alive and is a living being, but thereafter, as it is quenched and becomes concentrated, it turns into water and earth and things substantial" (Lapidge 1978, p. 183). Another Roman author, Marcus Tullius Cicero, adopted a version of the Stoic universe, such as appears from his treatise On the Nature of the Gods. We Stoics, he said, conclude that

in consequence of this consumption the thing... will come to pass, I mean the final conflagration of the whole universe; for when moisture has been exhausted the earth could not be nourished, and there would be no returning stream of air, as its creation would be impossible when the water had all been used up; nothing, therefore, they say, is left except fire as the agency, vivifying and divine, by which the universe should be renewed again, and the same external order called into being (Cicero 1896, Book 2, Chapter 46). It is tempting to think of the ekpyrotic state as a violent conflagration, perhaps a kind of 'big crunch' in which all matter collapses and is turned into hot radiation energy. But the Greek texts mostly describe the decay process as a very slow, almost imperceptible combustion. Some of them liken the conflagration of the world to the gradual transformation of swamps into dry grounds.
More than two thousand years later, the name 'ekpyrosis' reappeared in cosmology, now in a cosmological model based on concepts of string theory proposed by Paul Steinhardt, Neil Turok, Bert Ovrut and Justin Khoury in 2001. As they explained in their paper in Physical Review, "We refer to our proposal as the ‘ekpyrotic universe,’ a term drawn from the Stoic model of cosmic evolution in which the universe is consumed by fire at regular intervals and reconstituted out of this fire" (Khoury et al. 2001). The new ekpyrotic model depicted a kind of phoenix universe and was subsequently transformed by Steinhardt and Turok into an eternally cyclic model of the universe intended as an alternative to the standard inflationary scenario of the big bang. According to Steinhardt and Turok, the association to Stoic cosmology was suggested by two classics scholars, Joshua Katz from Princeton University and Katharina Volk from Columbia University (Steinhardt & Turok, 2007, p. 149).
Other modern authors have found a different kind of inspiration in Empedoclean and Stoic cosmology, seeing them as similar to the much later cosmological views of the twentieth and twenty first century, such as the steady-state theory of Hoyle and colleagues (2000), the quantum theory of an infinite universe which continually recycles itself (Joseph 2010a,b), or the relativistic theory of a closed cyclic universe with initial and final singularity (Ćirković 2003).
3. Cosmic Beginnings and Multiple Worlds
The cyclic universe is not the only modern cosmological idea that with some justification can be traced back to Greek-Roman antiquity, if of course only in a qualitative sense. The same is perhaps the case with the controversial idea of many universes – presently known as the multiverse – and its associated notion of the anthropic principle (Carr 2007). The cyclic universe of the Stoics thinkers constitutes one kind of multiverse, but in a temporal version only.
In sharp contrast to Aristotle, Epicurus (ca. 342-271 BC) advocated an original version of atomism according to which atoms moved ceaselessly in an infinite void, constantly forming and reforming the world. And not only that, for he also disagreed with Aristotle’s conclusion of the uniqueness of the world. Boldly stating that "there are infinite worlds both like and unlike this world of ours," Epicurus argued as follows: "For the atoms being infinite in number... have not been used up either on one world or on a limited number of worlds, nor on all the worlds which are alike, or on those which are different from these. So that there nowhere exists an obstacle to the infinite number of worlds." He further stated that "we must believe that in all worlds there are living creatures and plants and other things we see in this world" (Crowe 1999, p. 3; Trimble 2009).
Epicurus’ atomistic ideas greatly influenced the Roman poet Titus Lucretius Carus who about 50 BC composed his famous work On the Nature of Things (Latin: De Rerum Natura), one of the masterpieces of Greek-Roman natural philosophy. After having affirmed that the universe is spatially infinite--"All that exists... is bounded in no direction" --Lucretius proceeded with arguing for an infinity of inhabited worlds, of "other orbs of Earth in other regions of space, and various races of men and generations of beasts." He further explained that although the cosmos is infinite in space, it is of finite age and "there will be an end to the heaven and the Earth." He thus opted for a combination of space -time finitude-infinitude that was opposite to the one argued by Aristotle. Lucretius based his argument on the shortness of human history, which he found to be inexplicable if the world had existed eternally in the past:

"If there was no origin of the heavens and Earth from generation, and if they existed from all eternity, how is it that other poets, before the time of the Theban war, and the destruction of Troy, have not also sung of other exploits of the inhabitants of Earth? < How is it that they no where survive in remembrance, and are no where stamped on everlasting monuments of fame? But, as I am of opinion, the whole of the world is of comparatively modern date, and recent in its origin; and had its beginning but a short time ago" (Lucretius 1997, p. 45 & p. 205). According to Lucretius, not only did the universe have a beginning, it was also decaying towards a final end. "It is vain to believe that this frame of the world will last for ever," he wrote, "for neither do its veins, so to speak, submit to receive what is sufficient for its maintenance, nor does nature minister as much aliment as is needed." Here we have an early statement of what anachronistically can be considered the universal principle of dissipation or what in the nineteenth century became known as the heat death of the universe, supposed to be a consequence of the law of entropy increase.
The problem of the eternity of the world was raised by Stoic philosophers long before Lucretius. For example, Theophrastus reported how Zeno of Citium used the observed surface of the Earth, characterised as it is by mountains, valleys and plains, to argue that it could not have existed in an infinity of time (Freudenthal 1991, p. 50). This may be the first instance of a general line of reasoning that in the late nineteenth century was dicussed as the "entropic creation argument": From the existence of unidirectional natural processes, such as the steady increase of entropy, it can be inferred that the world is not eternal in the past (Kragh 2008).
Lucretius' reasoning has been read as "an almost modern formulation of the anthropic argument against the past temporal infinity" (Ćirković 2003, p. 883), which is a reference to what is sometimes known as the Davies-Tipler argument. The essence of this argument, due to Paul Davies and Frank Tipler, is that in an infinitely old universe one would expect colonization all over by technologically advanced civilizations. Since this is contradicted by observation, the world cannot have existed in an infinity of time (Barrow & Tipler, 1986, pp. 601-608). However, the Davies-Tipler argument is far from unproblematic and it is questionable if it qualifies as an anthropic prediction. At any rate, Lucretius' anticipation of the argument was not the only one of its kind and it is unjustified to speak of "the historical blindness of subsequent generations' to this form of argumentation (Ćirković 2003). In fact, from late antiquity over the middle ages and the renaissance to the modern period many philosophers and scientists have argued in similar ways for a universe of limited age (Kragh 2008).

An Ancient Greek Sighting of Halley's Comet?


Journal of Cosmology, 2010, Vol 9, IN PRESS
JournalofCosmology.com, July, 2010

An Ancient Greek Sighting of Halley's Comet? Daniel W. Graham, Ph.D.1, and Eric Hintz, Ph.D.2,
1Department of Philosophy Brigham Young University Provo, Utah.
2Department of Physics and Astronomy Brigham Young University Provo, Utah 84602

Abstract
The regularity of the orbits of comet Halley has made possible the determination of its visits backwards in time through the Middle Ages to antiquity. Computer models have provided correlations between reports of comets back to the second and third centuries BC and astronomical records of the Babylonians and Chinese. So far the earliest probable sighting is the return of 240 BC, confirmed by Chinese observers. Thus far ancient Greek records, which do not contain systematic diaries of heavenly events, have not been considered in this connection. One famous event recorded by Greek philosophers and historians is the fall of a meteor in northern Greece in 467/6 BC. At the time of the meteor, a comet was visible. This coincides with the retrodicted appearance of comet Halley in the summer of 466 BC. Using computer models we examine the probable path of comet Halley on that return and find it is consistent with reports about features of the observed comet. The philosopher and scientist Anaxagoras is said to have predicted the fall of the meteor. One ancient source corrects this confusion and allows us to see how the Greeks combined theory and observation in this case.
Keywords: Halley's Comet, Ancient Greeks, Aristotle, Anaxagoras.



Halley's comet is one of the most prominent visitors to the inner solar system. Using Newtonian theory, Edmond Halley in 1705 predicted the return of a comet seen in 1682, which duly returned in 1758 (after Halley's death) to make the predictor posthumously famous and acquire his name; the comet also provided a spectacular confirmation of Newtonian physics against rival theories, which soon faded from the competition. Its returns have been eagerly anticipated ever since. But the success in predicting returns has also allowed astronomers to project backwards the visits, first to 1607 and 1531, as Halley himself had done in developing his prediction, and then to earlier times. Study has revealed Halley's comet to be the harbinger of disaster in the Norman invasion of England in 1066, portrayed in the Bayeux Tapestry. Its appearances were recorded with fear an awe throughout antiquity and the Middle Ages.
Calculating appearances of comet Halley is not easy, since its orbits sometimes bring it close to planets whose gravity can modify its course. Its orbital period typically varies between 75 and 76 years, but can return in as few as 74 or as many as 79 years. Computer models made to predict or retrodict its visits must take into account gravitational interactions between the comet and the planets. Using computer models calibrated for actual and presumed alterations in the comet's orbit, its visits have been extended back into the third century BC. Detailed records kept by Babylonian observers on one side of the world, and Chinese observers on another, have allowed researchers to identify appearances of the comet in 87 and 164 BC (Stephenson et al. 1985). Chinese records make probable the sighting an earlier appearance in 240 BC (Kiang 1972), now the earliest known sighting of the comet. Yeomans and Kiang (1981) have made projections of earlier returns of the comet back to 1404 BC, when a near pass to Earth renders further calculations problematic without observations to correct them. They made their calculations "to allow possible identifications of ancient cometary observations with this famous comet" (p. 644). Thus it is in principle possible to find earlier sightings in ancient records, but such sightings are difficult to obtain because of the fragmentary remains of early astronomical records.
We wish here to propose a possible sighting drawn from Greek records that have not been considered in this connection. Whereas Babylonian and Chinese observers kept meticulous records of daily phenomena in the heavens for centuries, the Greeks do not seem to have kept similar records. While they made important advances in cosmological theory and in theoretical astronomy, they had no native bodies of data to draw on. Greek astronomers such as Hipparchus and Ptolemy seem to have drawn mainly on Babylonian records for the data they used in their theories (Neugebauer 1957, 1975; Hunger and Pingree 1999; Rochberg (2004). Hence it is not surprising that the Greeks have not furnished observational records with which to check the appearances of comets and the similar phenomena. Any records found in Greek sources are likely to be accidental in the sense of not arising from systematic habits of observation and record-keeping.
Notwithstanding the challenges posed by Greek sources, there is one event that left a mark on Greek astronomy and cosmology which offers the possibility of furthering our knowledge of comet Halley. In 467/6 BC a meteor fell in northern Greece which caused a sensation in the Greek world. Records of the event note that the meteor fell while a comet was burning in the sky. Ancient (and modern) commentators have mostly concerned themselves with the meteor while treating the comet as an interesting coincidental feature of the situation. We shall briefly rehearse the information about the meteor and then focus on the comet.
The meteor fell during daylight hours in the vicinity of Aegospotami ("Goat Rivers") in the Hellespont region of northern Greece. The meteorite was about the size of a wagon, and became a wonder to the inhabitants of the area–in fact it was a tourist attraction for over five hundred years (see reports cited below). It immediately became associated with the name of the philosopher and cosmologist Anaxagoras, who was said to have predicted the meteor's fall. Greek philosophers had been speculating about the structure and composition of the cosmos for more than a century before this event (Furley 1987; Wright 1995; Graham 2006; Gregory 2007; Sedley 2007). But there is no record of any awareness of meteors earlier than Anaxagoras. Early thinkers including Anaxagoras theorized about shootings stars, but tended to view the streaks of light they saw as meteorological events rather than as passages of meteors (Diels 1879; Mansfeld and Runia 1997, 2009). From this time forward, theories of meteors became common. This fact creates something of a quandary: how could Anaxagoras predict a phenomenon that was by nature unpredictable, and do it when the phenomenon itself was unknown? If the connection between Anaxagoras and the meteor is based on misconceptions, how reliable can the reports be? What is remarkable about the meteor is that, in a time when mythological thinking was common (philosophers proposed scientific explanations but presumably remained a small intellectual elite), the prodigious event of a meteor falling to Earth was never associated with any mythological action, but only with a scientific theory. This tends to suggest that Anaxagoras' theories were known and were seen to connect with the event. Anaxagoras was a member of Pericles' circle in Athens, and so was well known among the intelligentsia (Graham and Hintz 2007). According to his cosmological theory, the heavens consisted of naturally heavy stony or earthy bodies kept aloft by something like the centrifugal force of a cosmic vortex. Most other previous theories described heavenly bodies as fiery or cloudlike manifestations that were lighter than air. In this historical context, the fall of a stony body to earth would be seen as a confirmation of Anaxagoras' theory against rival models of the heavens (Curd 2007).
For our purposes the importance of the meteor arises from its dating. It fell in the year 467/6; or according to another report in 468/7 (The Marmor Parium --a marble stone from Paros with inscriptions of important events, composed in 264/3 BC-- in inscription 57 dates the meteor to the archonship of Theagenides, or 468/7 BC). The event was remarkable enough that it appeared in early chronicles and was passed on by thinkers interested in astronomy. Its date is fairly well set by the reports to within 468-66 (that is: summer 468 to summer 466). We should note here that early Greece had no standard calendar, with each city state using its own system of lunar months which had to be supplemented irregularly by intercalary months to keep in step with the solar year (On issues of chronology see Bickerman 1980). Hence there is room for some discrepancy in just translating an early local report to a later one using years of the Olympic games cycle or Athenian archons (magistrates) as reference points. Consulting Yeomans and Kiang's Table 4 (p. 643), we find an expected return of comet Halley in July of 466, which makes the meteor-comet event potentially interesting to modern astronomy. The obvious question becomes: is the comet observed in connection with the meteor of Aegospotami, which we shall call "Anaxagoras' comet," identical with comet Halley?
Let us look at three (of four) ancient reports of the comet: When the stone fell from the air at Aegospotami, having been supported by the wind it fell down during the day. It so happened that at the same time a comet was visible in the west. (Aristotle Meteorology 344b31-34)
The Greeks report that Anaxagoras of Clazomenae, in the second year of the 78th Olympiad [467/6] predicted, by his knowledge of astronomical writings, within what days a stone would fall from the sun, which happened in the daytime in a region of Thrace on the Aegos river. The stone is still exhibited, being about the size of a wagon load, of a burnt color, which fell while a comet was seen burning in the night (Pliny Natural History 2.149 = DK 59A11).
Some say the fall of the stone was an omen of this event [the Athenian defeat in a battle at Aegospotami, 405 BC], for an immense stone had fallen on Aegospotami, according to common belief. (2) (It is shown to this day by the inhabitants of the peninsula, who stand in awe of it.) It is said that Anaxagoras predicted that one of the bodies entangled in the heaven might, if there were some slip or agitation, break off and fall or be cast down; and indeed none of the stars is in its natural place; being stony and heavy they shine by resistance of the revolving aether, and being constrained by the angular momentum of the revolution they are dragged by force . . . . (4) In his treatise On Piety Daimachus supports Anaxagoras, reporting that before the stone fell, for seventy-five days a huge fiery body was visible in the sky, like an inflamed cloud, not still but moving with complex and branching motions, so that fiery fragments from its shaking and errant course flew in every direction, flashing like shooting stars. (5) But when it had fallen to earth there and the local inhabitants got over their fright and gathered around it, they saw no activity of fire, not even a trace, but a rock lying there, large indeed, but representing no appreciable fraction of that fiery mass above (Plutarch Lysander 12.1-5 = A12).
These reports provide good evidence for the event. Aristotle, a leading researcher and scientist as well as philosopher, writing a little over a century after the event, notes the synchronism of the meteor and comet and the daytime descent of the meteor. The comet was at the time visible in the west. Pliny gives the dating and confirms that the meteorite is still an attraction, writing five hundred years later (in the mid-first century AD). Plutarch, writing in the late first or early second century, himself a well-read scholar familiar with astronomical theories in general and Anxagoras' in particular, gives a brief summary of Anaxagoras' theory and repeats a description of the comet from an earlier historian. He makes it clear that it was Anaxagoras' theory that predicted the possible fall of a meteor; Anaxagoras did not personally predict this particular meteor. West (1960) has suggested that the presence of the comet might have led Anaxagoras to anticipate the fall of a piece of it. There are problems with this suggestion, however, because on Anaxagoras' theory comets are just conjunctions of planets. Hence we need not disqualify other less careful reports of the event, like Pliny's, as making patently absurd claims. Daimachus tells us that the Anaxagoras' comet was visible for seventy-five days and gives a vivid description of a major comet sighting (without using the word "comet").
The Greek reports lack the astronomical details that are found in Chinese and Babylonian diaries and that might help verify the path and exact timing of the sightings. Nevertheless, they do provide some important information, including the period of visibility. While this information cannot demonstratively confirm that Anaxagoras' comet was indeed Halley's comet, we can reconstruct the likely path of the latter to see whether it agrees with the observations recorded. Based on the orbital elements determined by Yeomans and Kiang we determined the orbital path of the comet through the inner Solar System. From the 1986 passage we determined the magnitude scaling based on the comet-Sun and comet-Earth distances. In addition we used the first naked eye observations from November 1985 to set a cut-off magnitude of 4.2 as the faintest possible level at which the comet could be seen (See Morris and Green 1982). Based on these assumptions we arrive at a reconstruction of the passage of comet Halley in 466 BC. In Fig. 1 we show the orbits of Mercury, Venus and the Earth from an overhead view. The path of the comet is then shown in black. The positions of Venus, Earth and the comet are shown for each day between these dates. Clearly the comet is in the appropriate retrograde orbit. In Figure 2 we show the X-Z motion of the comet with respect to the Earth to give a more complete picture.


Figure 1.

Figure 2.
From these figures we can piece together a picture of the comet's passage. On June 4th a close conjunction of Venus, Jupiter, and the moon occurred in the sunset. Comet Halley could have become visible soon after, on June 5th or 6th early in the morning very near the Pleiades. It would have grown in brightness each day, with the tail becoming more elongated. On June 4th the comet had passed from below the Earth's orbital plane to above it. Then a few days later on June 8th the comet would have passed inside the Earth's orbit. This could very easily have left material in for the Earth to pass through later in September. Later on June 28st the comet would have passed inside the orbit of Venus. (At no point does the comet pass inside Mercury's orbit.) On August 6th the comet would have passed very close to Venus on its way back out of the Solar System. Then on August 27th the comet would have moved beyond the Earth's orbit.
The almost parallel tracks of the Earth moving counter-clockwise and the comet moving clockwise would have kept them in close proximity for an extended period of time. On July 12th the comet would have made its closest approach to the Earth, 0.46 AU, followed quickly on July 18th by the perihelion passage. The comet should have reached its brightest magnitude of -0.4 during this time (see Fig. 3, plotting magnitude as a function of date). Because of the nearness of our planet and the comet, and the position of the comet in the sky, it might not have disappeared at the time of its conjunction with the sun, early on July 18th, but simply have moved from the morning sky east of the sun to the evening sky west of the sun, with its tail at least highly visible extending away from the sun and upward. The Earth would have moved under the tail of the comet, but might have intersected with the debris field from below the tail itself. The tail might have described a spectacular arc above the sun like that in figure 4. Since the tail of a comet can extend more than 1 AU, at the comet's closest approach to Earth the tail may have stretched more than 0.5 AU over and beyond the Earth.


Figure 3.
On July 21, soon after its perihelion passage, the comet would have been bright (0.3) and appeared right above a conjunction of Venus and Saturn. On August 9 the comet would appear near Venus, with the planet appearing at almost -4 magnitude and the comet at 2.7. The comet would become fainter and lower in the western sky until about August 25th it would disappear. Accordingly, it is possible that the comet was visible for about eighty days, depending on atmospheric conditions and the darkness of the sky. Fortunately, the summer is the dry season in Greece, when clear skies are the rule.
What we can say based on a computer model of the return of 466 BC is that the reconstructed appearance is consistent with the ancient reports we have. Comet Halley could have been visible for seventy-five days running. Unlike most comets, Halley would not have disappeared from the sky for several days around the perihelion, but might well have remained visible just before and just after the solar conjunction. This is important because, absent an adequate theory of comets, many ancient observers would take a comet appearing in the west at evening several days after an appearance in the east in the morning as a different comet (Anaxagoras understood comets as planetary conjunctions. See Aristotle Meteorology 342b27-29, Aetius 3.2.2. Earlier Xenophanes had seen comets as luminous cloud formations: Aetius 3.2.11).
Around the time of conjunction the tail should have been large and impressive as the Earth passed under it (see Fig. 4). While the Earth did not pass directly through the tail, it may have intersected with the debris field from it. This would have generated small meteors, consistent with the shooting stars reported by Daimachus as preserved in Plutarch.
[Insert Fig. 4 here.]
Aristotle also claims that the meteor associated with the comet was held aloft by winds.In general Aristotle holds that meteors and similar phenomena arise from exhalations in the atmosphere (Meteorology I.4); he does not, however, associate them specifically with winds, but rather with either combustion or compression (ibid. 341b31-342a1). In particular, sideways motion is caused not by wind but by an interaction of forces (342a24-27). In contrast, Aristotle associates comets with windy conditions (344b26 ff.). The summer season, after the solstice, is the time of the etesian or annual winds that blow strongly from the north over the Aegean sea. Aristotle Meteorology he identifies the beginning of the winds with the rise of the Dog-star (Sirius), i.e. in late July.If we take comet Halley to be Anaxagoras' comet, we should infer that the meteor fell after July 18th when the comet was in the western sky. None of this proves definitively that Anaxagoras' comet was Halley's comet.
Nevertheless, given the rarity of cometary events, especially encounters with major comets, we should consider comet Halley to be a strong contender for the comet associated with the meteor of Aegospotami. There remains the possibility of finding or identifying further ancient sightings of comets from Chinese and Babylonian records. The Greeks provide one possible reference point in the search, one that takes us back three orbits and 226 earlier than the earliest previous probable sighting. If Anaxagoras' comet is indeed identical with Halley's comet, it would add another important entry to the distinguished resumé of the most famous comet.

Cosmologies in Bronze Age Central Europe


Journal of Cosmology, 2010, Vol 9, IN PRESS
JournalofCosmology.com, July, 2010

Retracing Ancient Cosmologies in Bronze Age
Central Europe: A Prehistoric Puzzle
Emília Pásztor, Ph.D.
Magistratum Studio 6000 Kecskemet, Lestar ter 1. Hungary,

Abstract
In the lack of written and oral material, studying and discovering prehistoric cosmological ideas, requires the use of 'silent sources', such as special archaeological finds, iconography and symbols of decoration motifs, orientation of houses and graves. It follows from these 'building units' that archaeological methods should have primary role in revealing prehistoric cosmologies. A detailed description of the universe such as we have from ancient Egypt or India cannot be expected but we hope to find some essential/fundamental elements of prehistoric teachings on cosmos.
Keywords: Central Europe, Carpathian Basin, Bronze Age, sky lore, celestial symbols, Near-Eastern influence, Proto-Indo European, Proto-Ural.




1. Introduction
The responsibility of an archaeologist is not only to excavate, classify and describe artefacts but to study what the ancient peoples believed and what they thought of the world around them and how they conceived its origin. The archaeastronomy, coupled with the knowledge of the motion of the celestial bodies, can help reveal the role of the sun, the moon and the stars might have played in the life of ancient peoples and their understanding of the cosmos.
Consider, Central Europe, during the Bronze Age. Megalithic monuments as three dimensional sources and rock carvings and discs are often found in this area which have cosmological significance (Fig 1).


Fig 2. Map of Europe designed by Zoltan Török The bronze Nebra Sky Disk is from Central Europe, near Nebra, Saxony-Anhalt in Germany, and is dated to c. 1600 BCE. It has been associated with the Bronze Age Únětice culture and is 32 cm diameter and inlaid with gold symbols representing the sun or full moon, a lunar crescent, and stars including what appears to be the Pleiades, the Milky Way, and symbols (two golden arcs and curved strip). These symbols of the sun, moon, stars, the Pleiades, and the sunrise and sunset are all eloquent testimony of a Bronze Age worldview, in which the natural elements had significant importance (Pásztor & Roslund 2007).


Fig 2. Nebra Sky Disk
Without written sources, archaeological finds, such as the Nebra disk, serve as essential 'foundation-stones' for studying the cosmology of ancient peoples. The orientations of special archaeological monuments or rather structures, of houses and cemeteries, of decorative motifs or symbols all can be offered as initial points to retrace cosmological understanding.
Abstract signs are characteristic of Bronze Age artefacts in the Carpathian Basin, including decorations with obvious celestial and cosmological significance. However, the meaning of a symbol cannot be 'deciphered' only from the form of the sign or its apparent similarity to something else. Therefore, its use and its role among other signs or motifs and the social and religious context should be investigated to obtain a detailed understanding. Also searching for analogies is important. The existence of an organized belief system, can be considered a resource especially if some basic elements of the ancient sky lore are included.
However, help is needed, to make the archaeological finds speak. The sources for studying the ancient cosmologies include (Pásztor 2009a):

1: anthropological – ethnographical research on the characteristics of the folk/traditional worldview, 2: The cosmological notions of communities in cultural interactions with the Carpathian Basin:
the cosmological interpretations of Near Eastern literate societies the Bronze Age Scandinavian cosmology with assumed universal elements 3: Possibly contemporaneous ancient cosmologies such as the Proto-Indo-European and Proto-Ural.
2. Characteristic Features of the Archaic Traditional Worldviews
All people have beliefs based on their interpretations of the origin and functioning of the surrounding world: the earth, the sky and natural phenomena. These conceptions vary and differ from group to group, although they have general features which are common to the mythologies of many peoples. Anthropology, ethnography and ethno-archaeology can mostly help cognitive archaeology with answering questions as to the shared vs unique nature, meaning, and foundations of these beliefs.
According to the basic rule of searching for analogies, their application first requires the careful analysis of the data. It is an essential condition that the cultures being compared should have a similar ecological background, as the natural and economical contexts are significant in the formation of cosmology (Szabó 1990). As the celestial, astronomical phenomena depend on the geographical latitude, latitude should also be a condition in studying ancient cosmologies.
The traditional worldview is influenced by personal experience, traditional and cultural interactions. Traditional people also tried to interpret the events observed in the natural world by projecting the known order of the human world onto these experiences. Thus the social structure of each society is also important in revealing the archaic cosmology.
Despite the fact that the traditional worldview is not unified, not homogeneous, not free from contradictions and always changing (Pócs 199o, p. 527-543), comparative studies have discovered some archaic features, which can be found in the mythology of many peoples, that is why they can be used as analogies for the present purpose.
A universal motif is the duality of the sky and the earth. It is also a general feature of these ancient motifs that the earth is a flat disc, covered by a cup-like solid firmament which has several layers (3, 7, 9, 12) whose numbers can have different meanings for different cultures or regions. These universal motifs are part of European peoples' mythologies such as Greek and German mythologies, but are also found in the Ural-Altai mythologies. There are many artifacts which might represent this belief. For example, concentric circles may be the symbol of the multilayered world, though some have mistaken these circles as representing the sun. The Sun with several levels is not known from any myths, thus the concentric circles cannot be symbolic of the Sun (Fig 3).


Fig 3. Late Bronze Age clay disc with diameter of 95 cm, Saghegy, Hungary, photo: E. Pasztor. In many cosmologies, the duality of the sky and the earth evolved into a trinity of sky, earth and underworld . The underworld is generally the dwelling place of the dead, an earth-womb where the dead might be reborn, or where they, along with demons, dwell for all eternity (Joseph 2000a,b). The middle world is for the humans, the upper world belongs to the celestial beings. The concepts of the world-centre/ tree/ axis (axis mundi) and the world trinity are universal elements of the Ural-Altai, the Central and Inner Asian, the Indo-European (Slavic, Germanic) and the Iranian mythologies. They are also considered the significant character of shamanistic world view of the hunting and pastoral tribes (Pócs 1990, p. 53o).
Another typical element of many cosmologies is also the mound/mount, perhaps with a world tree on its top and the sun and the moon at each side of the tree. The mound standing on the centre of the world often participates in the creation of the world. The long continuance far back in time of the sacral assemble of the mound, the tree and the female principles have been demonstrated by Central Asian oral tradition, ethnographic and archaeological artifacts (Hoppál 2009). Some archeological finds in the Carpathian Basin seem to carry this cosmological motif as well.
3. The Cosmological Notions of Communities in Cultural Interactions with the Carpathian Basin
A cultural interaction with Anatolia and the Near East can be detected in the archaeological material before the third millennium BCE. In the Neolithic and Copper Age (the period between the 5th and 3rd millennia BCE) the finds signal not only cultural interactions but migrating people as well. The invention and development of bronze casting raised the frequency of long distance trade and changed trade significantly which sped up the information exchange as well. The luxury items found in the Syrian royal tombs dated to 1340 BCE were made by local craftsmen from amber of Baltic origin (Mukherjee et al. 2008). Thus, the route later called the Amber Route which connected the Baltic region with the Mediterranean must already have existed in Bronze Age.
Amber, this northern raw material, may have travelled to the Near East and the ancient Syrian ports crossing the Carpathian Basin and the Aegean. On this route not only the trade goods but also the ideas and beliefs were migrating thus some elements of the Mesopotamian cosmology must also have reached the Carpathian Basin, although it might not be possible to prove it since the influence seen on the artifacts cannot be differentiated from the universal cosmological features. One such example is the basic assumption that besides the visible sky vault and the earth the world is divided into several layers whose number is different by time and regions as previously mentioned (Horowitz 1998).
Mesopotamian cosmology is however a generic term, as several creation myths and world interpretations existed and they do not necessarily mesh with each other. Although the creation myths belonging to different towns and regions contain many similar elements, the local variations differ from each other in several details. The remaining texts were set down in early 2nd millennium BCE, although their oral traditions go back to early 3rd millennium BCE. Most of the myths reflect the period of town states. The systematization of the cosmological components is the mixture of empirical observations and theological speculations like in the archaic world interpretations.
It is indisputable that there are some celestial symbols found in the Carpathian Basin that have clear connections with Mesopotamia. There are several late Middle Bronze Age (14-13th century BCE) pendants bearing abstract symbols whose analogies can be found among the Near Eastern astral symbols (Pásztor 2010). The crossed circle appeared during the Neolithic period in the Carpathian Basin which cannot be found in the rest of Europe except in the Balkan and the South-East Europe. During the Bronze Age this symbol became a real universal as it spread throughout the whole continent (Fig 4).

Fig 4. Hoard of Bronze Age jewel, Koszider period, 14-12th BCE, Hungary, photo: courtesy of Intercisa Museum Dunaujvaros.
Although it is generally considered to be a solar symbol, its meaning is likely to be more complex and preferably associated with the (micro)cosmos or the sky. The other similar symbol with the addition of one dot in each quarter (Fig 4) may be the symbol of the most favorable Near Eastern goddess Ishtar/Astarte who must have been the divine representative of the bright planet Venus in the Koszider period (14-13thcentury BCE).
Although there were also female figurine pendants with astral symbols which were nearly identical with the ones of the Koszider period, this was not the case with the Carpathian Basin ones where the anthropomorphic representation is missing. The respect or worship of the transcendent forces might not have taken anthropomorphic shape, yet. As in all probability the eye-catching natural phenomena and the celestial bodies played an important role in the belief system, the symbol of the divinized Evening star was easily taken over and might have been used for same magical protective purpose.
As the other end of the trade route stopped in Northern Europe, they might have also shared beliefs with those of the Carpathian Basin. The identical sacral objects of Hasfalva (Hungary) and Bålkakra (Sweden) are clear evidence of it (Fig 5).


Fig 5. Almost identical Early Bronze Age sacral objects from Bålkakra , Sweden and Hasfalva, Hungary/Austria. According to one of the basic assumptions of the Nordic Bronze Age cosmology there were universal elements of the European Bronze Age belief system that are shared with Western Asia. A general sun cult is believed to be characteristic of most ancient people. In order to support this, unique finds from different periods and different sites are listed. Besides the double spiral, the four-spoke- wheel, the horse, the ship; the sun bark motif of the Urnfield culture seem to be wide spread in Bronze Age Europe. The sun bird – sun bark motif like an emblem might signal an emerging organized religion of the late Bronze Age in most parts of Prehistoric Europe.
5. Possible Ancient Cosmologies of the Same Period
The ancestors of most of the present European people spoke such languages that belong to the Proto-Indo-European (PIE) family. Their mythologies also share cosmological elements which point to a possible common cosmologies. Although the emergence of the PIE belief system in the Carpathian Basin has not yet been determined; its presence is clear by the Bronze Age. According to the most frequent myth, the world was created by the dismemberment of a divine being (Lincoln 1986) whose face and eyes might have given the sun, its mind became the moon and the firmament came from the skull. Although in the Bronze Age there is no evidence to support it, the intentional fracture of the Neolithic idols might have been caused by the introduction of this cosmological myth. According to another well-known version originating in 1700-1100 BCE the divine hero conquered the demon and tilting its lance, which becomes the world column in the middle of the world then, into the primeval mound and releases the waters enclosed. This leads to the separation of heaven and earth; the sky vault becomes supported, the sun and the moon emerge from the depths of the water, light was born, and the cardinal directions are created (Irwin 1990).


Fig 6a and b. Prestige grave finds, pin and dagger, Branč, Slovakia. Golden disc, stray find, Székelyhíd, Transylvania/Hungary. Beside the PIE cultural impact the indigenous cosmological beliefs must also be hidden in the archaeological finds which suggest a highly diverse belief system. A hunter-gatherer worldview differs form an agricultural one. The Proto-Ural cosmology for the 3rd millennia BCE retraced by Vladimir Napolskikh (2002) offers a good example for the previous one. A significant element is the diving loon, one of the water birds that have a connection with both the underworld and the sky world. The South is the most favourable direction while the North is associated with the devil and the death.


Fig 7. Bird pendant from a hoard, Rozvagy, Hungary. 6. The Carpathian Basin
The above listed historical and anthropological results can give inspiration to launch detailed investigations to retrace prehistoric cosmological elements. These analogies are however, far from the Carpathian Basin in time or space. Without written sources the archaeological finds should be the primary material and archaeological methods should be the primary approach in recreating this ancient worldview. The first signs indicating a wide-spread evolving unified belief system possibly appear just during the Central European Urnfield culture (12-9th century BCE). If there is no common belief system or religion, no single cosmology can be expected. This argument is valid for the entirety of prehistoric Europe.
Recent research proves the high diversity of cosmological notions. A unified, organized cosmology cannot be argued for the time period of the Bronze Age, perhaps even for a single ancient European community either. The different prehistoric cultural groups (called archaeological cultures) apply different symbolic system, different house orientations, and grave orientation. The impact of the local traditions at a site often proves to be stronger than the assumed shared beliefs. The orientations of houses of many sites show preference of North – South direction in aligning the longer axes which is not the best considering environmental purposes. They must have been under the control of a belief instead, perhaps an indigenous one. If the main entrance facing east served as the guiding principle for the foundation, the Indo-European influence might have taken priority over the local heritage. The second most frequent alignment of the long axes concentrates around 140 degrees South of East, that is just a few degrees more than the direction of winter solstice sunrise at the horizon. The deceased are often laid facing the sun path in graves (east). The exchange of goods between the neighboring communities however, might cause virtually shared beliefs. These findings do not provide clear proof of a sun cult. In the Carpathian Basin certain relationship between artifacts and sites can be attributed to beliefs like animism (Pásztor 2009b).
The most characteristic find of Bronze Age in Europe is depositing things in the earth, that is burying things. The components and circumstances of the discovery of burials, depots and hoards significantly differ from each other which may mark different social expectations as well. Most experts argue that the sacred function enjoys priority, especially in the case of hoards deposited in wet places such as bogs, rivers, lakes or near them. This phenomenon seems to be universal during the whole Bronze Age and the high number of wet sites signals frequent ritual activity. This is not completely identical with those found in the Carpathian Basin as in many cases valuable hoards were found in dry places such as hill-sides, hill tops and the base of hills, the base of rocks, on arable lands, etc. and they were ritually arranged. It was common to offer weapons to gods as votives during the Bronze Age. In Central Europe this custom ended at the end of 8th century, although in North Germany and South Scandinavia it lasted 200 years more. Most of the hoards, especially the treasures, had no profane function. Thus, the artefacts that comprise the sacral depot are not everyday goods but emblems endowed with special meaning. Thus ritual hoarding always signals the importance of the sites as they were the spots where transcendental relations, exchange between the gods or spirits and the worshipper were established. Anthropological reports say that the ancient sacral places can usually be found in nature. It is characteristic of the belief system of many non-urban peoples and traditional societies that many elements of the surrounding world own a vital force similar to that of the human beings' therefore they have to be respected.
The natural forces, the transcendent powers are, however not considered fundamentally evil but that can be dangerous if they do not keep good relations with them. The sacral natural places are of power and the active part of the communal ceremonies, the cosmology and the manifestation of the sacral landscape. The depositing customs harmonize with the ethnographical cases therefore we may assume that also in the Bronze Age all geographical features had their own spirits from which the watery transcendent forces were the most respected. The sky worship can hardly be supported by hoarding sites. The hill top hoards or the golden ritual treasures might have relations to celestial powers although these are only assumptions. Anthropological research reports about different ceremonies performed at the same sites involved sky worship as well. However, the respect of spirits was not unified which might be the reason for depositing diversity.
7. Conclusion
The research on Bronze Age cosmology gives evidence of the diversity and the almost unsolvable mixture of intricate influences. Thus the Bronze Age cosmology is argued to be not homogenous, not free from contradiction and changes as time is passing. This is clearly indicated by the increasing number of the celestial symbols on prestige artefacts in the late Middle Bronze Age (14-1200 BCE) in the Carpathian Basin which might signal changes in ideology or belief system. The real, practical nature knowledge hidden in orientations and symbols is however, very scarce and consists of simple elements observed in nearby surroundings. Therefore one should beware of enthusiastic overstatements on 'deep' prehistoric knowledge of astronomy. To reveal and evaluate the astronomy or rather sky lore of an ancient community orientations and symbols are not enough. Without archaeological, religious - historical, and anthropological background knowledge they are unsubstantiated. Results of great value of prehistoric European astronomy and its application can be reached just by complex investigational methods in which archaeology must have the leading role. The surviving material remains are a tiny but essential piece of a historical puzzle which can never be fully assembled. Fig 8-9.


Fig 8. Golden armlet with rich cosmological symbols, Dunavecse, Hungary. photo: courtesy of the National Museum.

Fig 9. Golden arm ring with moon symbols, Magyarbenye/Biia, Hungary/Romania, photo:courtesy of the National Museum. Acknowledgments: The author would like to acknowledge Judit P. Barna, Jarita C. Holbrook and Maria Fekete for their valuable comments on the preliminary versions of the paper.

Inca Solar Orientations in Southeastern Peru


Journal of Cosmology, 2010, Vol 9, IN PRESS
JournalofCosmology.com, July, 2010

Inca Solar Orientations in Southeastern Peru Steven R. Gullberg, Ph.D.
Centre for Astronomy, James Cook University, Townsville, Queensland 4811, Australia
College of Liberal Studies, University of Oklahoma, Norman, Oklahoma, 73072, USA

Abstract
The Incas venerated many features of both natural and man-made landscapes that they felt to possess supernatural powers. In Quechua these shrines were known as huacas, and soon after conquering the Inca Empire the Spaniards began a campaign against indigenous religion that included a systematic eradication of such shrines. Those that were large carved stones and outcroppings survived, however, and form part of this study. Many were found to have astronomical meaning, marking events such as the solstices and equinoxes.
Keywords: archaeoastronomy, Inca, huaca, shrine, pillar, sun, moon, solstice, equinox, zenith, anti-zenith, nadir.




1. INTRODUCTION
The Incas practiced solar worship and considered their emperor to be the sun’s direct descendant, "the son of the sun." As such, evidence of astronomical veneration should abound and this study searched for solar orientation in features found at 29 sites surrounding Cusco, within the nearby Sacred Valley, and in the area between Machu Picchu and Llactapata (Figures 1 and 2). The sites selected were taken from those presented by Bauer (1998), Hemming and Ranney (1982), Gasparini and Margolies (1980), and Malville (personal communication).
Many features of the Andean landscape were worshiped by the Incas as they felt them to be endowed with supernatural powers. Cobo (1990 [1653]: 44-45) stated that the Incas venerated large trees, roots, springs, rivers, lakes, hills and mountains. He continued "They also did reverence to these places and made offerings," and that they worshipped anything natural that was perceptibly different. "All of these idols were worshipped for their own sake, and these simple people never thought to search or use their imaginations in order to find what such idols represented." These shrines were called huacas and were systematically worshipped and cared for and were integral parts of Inca religion and culture. They often were shrines to ancestors who, it was believed, could influence the living. The most powerful huacas required maintenance, care-taking, and offerings. Salomon and Urioste (1991: 17) state that "a huaca was any material thing that manifested the superhuman: a mountain peak, a spring, a union of streams, a rock outcrop, an ancient ruin, a twinned cob of maize, a tree split by lightning." Twenty-three of the sites studied were either carved rock huacas or sanctuaries that included carved or otherwise significant rocks. The remaining six sites were huacas or sanctuaries with structures, but lacked intrinsic rock shrines. These rock and non-rock huacas were categorized further as to whether or not they exhibited any potential astronomical orientation. Field research in the Region Surrounding Cusco included huacas at 19 locations, seven sites were in the region of the Sacred Valley, and the remaining three sanctuaries were related to Machu Picchu (Figure 2).


Figure 1. Peru and Cusco (modified from Zuidema, 2008).

Figure 2. Locations of the research sites listed in Tables 1, 2, and 3. The remaining sites in the Region Surrounding Cusco that are not depicted here due to scale are located near Cusco (lower right) on its northern through eastern sides (modified from Hemming and Ranney, 1982). Many facets of Inca astronomy were examined. Photographic evidence of light and shadow effects was recorded and solar orientations were cataloged. Research considered astronomical sightlines and/or light and shadow effects at times of the solstices, equinoxes, and zenith and anti-zenith (nadir) suns. Zenith passage occurs within the tropics on the two annual dates when the sun is directly overhead and vertical objects cast no shadows. The anti-zenith, or nadir, occurs on the two dates when the sun is directly beneath the observer on the opposite side of the world. This cannot be viewed directly, but Zuidema (1981b) describes Inca marking of the anti-zenith as taking place with a solar horizon observation when the sun sets 180° from the position where the sun rose on the day of zenith passage.
2. METHODS
The solar horizon orientations of azimuth and elevation were measured by using a sighting compass and supplemented where necessary with a surveyor’s transit. GPS coordinates of latitude, longitude and altitude above sea level were recorded at all locations for subsequent trigonometric comparisons. Orientations of features for sunrise or sunset at significant times of the year were documented. Specific locations of sunrises on mountainous horizons were accounted for with spherical trigonometry. Light and shadow effects at the huacas were recorded by digital imagery.
Huacas were first classified by region and then divided into two groups – those that were or included rock shrines and those that didn’t (Tables 1, 2, and 3). Further division regarded astronomical orientations, or lack thereof. For the purposes of this study a huaca was considered astronomical if it, or an element of it, was found to have a solar light and shadow effect or orientation(s) related in any way to the sun. If an orientation was found to exist and was available for potential use it was included. This was the case with certain east-west alignments that might have been used at the time of the equinoxes, even though it remains to be proven that the Incas were concerned with horizon positions of the sun on those days.
3. RESULTS
Solar orientations were found to be common in the huacas of this study. Of the 29 shrines examined 23 were found to fit at least one of the specified criteria. Sixteen of the sites included ceremonial rocks with solar orientations and seven more had structures oriented with the solar horizon. The sixteen sites that include rocks with solar horizon orientations are categorized as "Astronomical Rock." The remaining sites displaying celestial alignments were placed in the "Astronomical Non-Rock" category. Five sites with boulders displayed no evidence of solar orientations and were categorized as "Non-Astronomical Rock." These mainly were huacas among those in the study closest to Cusco and likely served purposes independent of the sun. One site without a rock or specific solar alignment was placed in the "Non- Astronomical Non-Rock" category. The existence of astronomical orientations at 79% of the sites studied supports that many Inca huacas were associated with solar observation and ceremony. If equinoxes are discounted then this figure lowers to 72%. Percentages are shown graphically in Figure 3.

Table 1. Huaca Classifications for the Region Surrounding Cusco.

Table 2. Huaca Classifications for the Sacred Valley Region.

Table 3. Huaca Classifications for the Machu Picchu Region.

Statistics regarding the specific types of solar events observed at the individual huacas are of particular interest. Nineteen of the solar huacas were found to exhibit orientations for the solstices and nine displayed specific effects of light and shadow. Seven had east and/or west orientations that potentially included the equinoxes and five had zenith or anti-zenith (nadir) orientations (Tables 4, 5, and 6). Ten of the sixteen astronomical rock huacas had orientations for the June solstice sunrise, six for the June solstice sunset, nine for the December solstice sunrise and four for the December solstice sunset. Five had east orientations with possible utility at an equinox sunrise and three had west orientations with similar potential for an equinox sunset. There were three instances of zenith sun orientations and one anti-zenith (nadir) orientation.
The number of examples for June and December solstice is fairly even, somewhat unexpected since the solstice in December is in the rainy season when observations of the horizon on specific days would be expected to be far less reliable. There is a marked difference between the numbers of orientations for solstice sunrises in both seasons when compared to those for the associated sunsets. The data implies a much greater ceremonial interest in the rising sun.
Two of the seven astronomical non-rock huacas had June solstice sunrise orientations, none for the June solstice sunset, three for the December solstice sunrise and none for the December solstice sunset. Of the 23 huacas with any astronomical association 22 held at least one orientation for one of the six primary solar horizon events of sunrise and sunset at June solstice, December solstice and the equinoxes. If the equinoxes are removed then this number of huacas becomes 19. There were a total of five possible examples of zenith sun alignments and two instances of potential alignments related to the anti-zenith (nadir) sun. June solstice sunrise orientations were noted 19 times in all (including multiple instances at the same site), June solstice sunset 7 times, December solstice sunrise 12 times, December solstice sunset 8 times, east/equinox sunrise 10 times and west/equinox sunset 9 times.
Ninety-six percent of solar huacas appear to have incorporated direct observation of horizon events when both solstices and equinoxes are included, and 83% when the equinoxes are not.

Table 4. Huaca Astronomical Orientations in the Region Surrounding Cusco.
Legend: JSSR–June Solstice Sunrise DSSR–December Solstice Sunrise ESR–Equinox Sunrise
JSSS–June Solstice Sunset DSSS–December Solstice Sunset ESS–Equinox Sunset


Table 5. Huaca Astronomical Orientations in the Sacred Valley Region.

Table 6. Huaca Astronomical Orientations in the Machu Picchu Region.

Percentages for each solar feature per huaca category are given in Figure 3. By definition all shrines in the Astronomical Rock Huaca category had at least one orientation for a solar horizon event. Solstice sunrises played a prominent role in certain annual Inca festivals, and orientations for sunrises on the June and December solstices were found to be the most common. Astronomical Rock Huacas led or tied in all but the zenith and anti-zenith categories when compared with the Astronomical Non-Rock category. This reversal, in part, is due to the nature of the Astronomical Non-Rock sites (Tables 1 and 3) where astronomically aligned features were constructed rather than carved into rock. The overall lesser occurrence of zenith-related orientations makes this difference less statistically significant, but would seem to imply that such observations may have been less common in the more highly represented rural areas of this study, although they were reported to have been of significant interest within the limits of Cusco (Zuidema, 1981b). Clear sightlines outside the city facilitated solar horizon observations, while vertical zenith observations could readily have been performed among urban structures.


Figure 3. Percentages of Astronomical Orientations per Huaca Category.
Legend:
JSSR–June Solstice Sunrise DSSR–December Solstice Sunrise ESR–Equinox Sunrise
JSSS–June Solstice Sunset DSSS–December Solstice Sunset ESS–Equinox Sunset
Ast Rock- Astronomical Rock Ast NRock-Astronomical Non-Rock.
4. DISCUSSION
This section provides illustration and discussion of orientations found at several of the sites that were explored. Examples such as the "Eyes of the Puma" at Kenko Grande demonstrate a considerable knowledge of horizon astronomy and the degree of the creativity that the Incas were capable of in the development of their shrines. On the top of the outcrop they carved two cylinders that form the puma’s eyes and then created a fissure in a nearby wall that allows light to fall upon those carved cylinders appropriately during the June solstice sunrise in a manner that completes the "puma" visual effect (Figure 4). The puma was one of three creatures most venerated in Inca cosmology - the condor being associated with the world above, the puma with this world, and the snake with the world below.


Figure 4. The "Eyes of the Puma" at Kenko Grande. The chamber within Kenko Grande exhibits traditional motifs such as niches and steps. The primary altar is finely carved and may have served in one or more types of ceremonial functions. The opening in the cave’s upper northwest corner admits light that could have been reflected by gold plates in the niche below it to illuminate the entire chamber. During the time surrounding the June solstice it also facilitates an effect of light and shadow on the ceremonial steps beneath it that are adjacent to the primary altar (Figure 5).


Figure 5. Kenko Grande’s internal ceremonial steps. Lacco’s caves demonstrate the interest and ability the Incas had for solar orientation. Each of the three has altars that the Incas illuminated at certain times by the sun or moon. The Northeast Cave’s altar is fully illuminated in the early morning on days approaching, during, and following the June solstice. On the horizon shown in Figure 6 the point of sunrise emerges from the right (east) and progresses daily toward the center. At the solar standstill (when the apparent travel of the sun stops near and on the day of the solstice), the alignment of the center of the cave opening with the sunrise is striking. The sun’s rays fall directly upon the cave’s altar and reflections brightly illuminate the rest of the chamber. The point of sunrise in the center of Figure 6 has reached its maximum extent to the left. After the solstice the movement of sunrise on the horizon reverses direction and proceeds back to the right.


Figure 6. June solstice sunrise from Lacco’s Northeast Cave. The Southeast and Southwest Caves incorporate specifically oriented light-tubes to admit the rays of the sun or moon. The Southwest Cave is the smaller of the two and also has a smaller altar. Its light-tube’s alignment with the path in the sky traveled by the sun and moon was shown on October 26, 2006 by the crescent moon displayed in Figure 7.


Figure 7. Crescent moon through light-tube of Lacco’s Southwest Cave. The Southeast Cave appears to have been the most prominent of the three as evidenced by the degree of workmanship in its sculpture, complete with fine carvings of a puma and snake near its entrance and the highly polished altar within its inner chamber. The altar is of an appropriate size and height for ceremony and sacrifice and is brilliantly illuminated by the sun near the time of zenith passage when it is overhead at 90° above the horizon (Figure 8).


Figure 8. Illuminated altar in Lacco’s Southeast Cave. Located between Kenko Grande and Lacco is a small huaca (Solar Horizons) with two carved circles that exhibit orientations for the horizon positions of solstice and equinox/east-west solar events (Figure 9). I first measured the east-west orientations of the circles and then recorded the additional orientations for the solstices. For reasons yet to be determined, watching sunrises and sunsets on days of the soltices and equinoxes appears to have been important here. The many seats carved upon the huaca underscore this relationship as there is at least one oriented for each of the associated solar risings or settings, with the exception of the June solstice sunset where that part of the outcrop has eroded extensively.


Figure 9. Orientations found at the huaca of Solar Horizons. Spanish chroniclers recorded solar pillars on the horizons of Cusco but all were eradicated, presumably in the post-conquest Catholic purge of Inca idolatries. Their locations were recorded, but there are no extant remains in Cusco. Two pillars near the modern village of Urubamba lie above Huayna Capac’s palace, Quespiwanka, give credibility to the Cusco reports, and enable direct study of this form of horizon astronomy (Figure 10). These towers on the Cerro Sayhua ridge demostrate the feasibility of this method for marking the June solstice sunrise when viewed from the vicinity of a granite boulder in the center of the palace courtyard. Their alignment supports Bauer’s and Dearborn’s 1995 hypothesis with regard to these pillars as well as Niles’ (1999) suggestions regarding the prominence of the granite boulder and an adjacent platform, no longer extant, that she argues were central features of Huayna Capac’s palace grounds. The utility of the boulder and platform as the focal point of the plaza is supported by this orientation and, to a lesser extent, by other potential alignments with natural horizon features for the December solstice sunrise and the June solstice sunset.


Figure 10. The pillars on Cerro Sayhua. The ceques of Cusco served as a system of intangible lines to connect, organize, and facilitate the care for the many huacas that surrounded the city. Polo de Ondegardo (1965 [1571]) tells us that each Inca village had ceques connecting shrines and it appears possible that such an organizational system may have been established at Machu Picchu, smaller but similar to the one in Cusco. Within Machu Picchu the Sacred Plaza is part of an oriention for the June solstice sunrise and December solstice sunset and might possibly have formed one end of what could have been an intentional ceque that included Llactapata’s Sun Temple and the River Intihuatana (Figure 11). An additional potential ceque is found in the alignment of Llactapata’s Overlook Temple with the River Intihuatana and Mt. Machu Picchu. These alignments of huacas near Machu Picchu lend themselves in support of the concept that ceques existed away from Cusco and ultimately may serve to validate Polo de Ondegardo’s claim.


Figure 11. Machu Picchu, Llactapata, and the River Intihuatana (modified from Malville, Thomson, and Ziegler, 2006). The 2003 rediscovery of Llactapata has given rise to many new questions regarding the overall extent, orientation, and function of the entire Machu Picchu ceremonial complex. Its many structures represent a significant enlargement of the overall estate and lend support to the possibility that a ceque system here organized huacas similarly to the one found in Cusco. The orientation of the stone-lined channel at the Sun Temple of Llactapata with the River Intihuatana and Machu Picchu’s Sacred Plaza is impressive (Figure 12), especially so when viewed from Llactapata at sunrise on the time of the June solstice. An orientation with the first rise of the Pleiades star grouping after it emerges from passage behind the sun also exists from Llactapata’s Sun Temple. Pleiades observations were a part of Inca predictions for crop success.


Figure 12. Alignment from Llactapata’s Sun Temple to the Machu Picchu Sacred Plaza. The River Intihuatana (Figure 13) may have played a much more significant role in the overall complex surrounding Machu Picchu than was previously thought. An intihuatana is said to have been a "hitching post of the sun," or a place where the sun was ceremoniously tied to prevent it from disappearing as it grew progressively lower in the winter sky. This term, however, might be a more modern invention. The River Intihuatana provides a distinct link between the structures of Machu Picchu and Llactapata and serves as a part of two axes between them. In addition to lying in line with the Llactapata Sun Temple and Machu Picchu’s Sacred Plaza, the River Intihuatana also is part of an east-west/equinox alignment between Llactapata’s Overlook Temple and Mt. Machu Picchu. These orientations emphasize the potential significance of the River Intihuatana as it is positioned at the junction of these two prominent axes. The locations of Llactapata’s Sun Temple and Overlook Temple may have been specifically selected to form these alignments.


Figure 13. The River Intihuatana 5. Concluding Remarks
The Incas were practitioners of solar worship and, as such, a logical assumption is that they might have designed many of their important buildings and shrines with features related to their veneration of the sun. This study set out to find evidence of solar orientations and/or effects of light and shadow at 29 sites in southeastern Peru. Overall 23 of these sites, or 79 %, were found to have at least one astronomical orientation. Features aligned for the solstice sunrises were found to be more common than the rest and slightly more of them were associated with the June solstice than were those for the solstice in December. The solstice sunsets were also notable, but of somewhat lesser relative interest. Also found were east-west orientations and as well some related to the zenith and anti-zenith suns.
The hypothesis of this study was therefore supported. As shown by the many examples identified in the research, a picture emerges of a culture interwoven with cosmology and astronomy. The Incas possessed celestial knowledge and as solar worshippers they chose to incorporate orientations and effects related to the sun, their god, in many of their temples and shrines. The huacas of this study point to a society that was both devoted to the sun and that possessed the technical ability to use their celestial knowledge in the design of any structure or carving.

Acknowledgements: The assistance of Kim Malville was indispensible, as were the suggestions of Tom Zuidema, Ken Wright, and Bernard Bell. Carlos Aranibar provided excellent support in the field and I am greatly indebted to Mike Zawaski who assisted the project with both insight and theodolite measurements. Jessica Gullberg, Steven Gullberg II, Gregory Gullberg, and Jesus Villafuerte also contributed to the fieldwork.