Thursday, October 21, 2010

Astronomy in Ancient Egypt

Think 'Egypt' and most people think of pyramids, not astronomy.
When one thinks of Ancient Egypt, pyramids, hieroglyphs, and mummies come to mind, not astronomy. However, unbeknownst to many who are more conscious of the more popularized aspects of Ancient Egypt, the Ancient Egyptians left quite as astronomical legacy, too.

Trying to trace the history of Ancient Egypt is difficult as Egypt (along with the Fertile Crescent) can be considered the birthplace of civilization. By 7,500 B.C., the first permanent settlements were already in existence in the Nile Valley. By 3,500 B.C., two distinct kingdoms, Upper Egypt in the South and Lower Egypt in the Nile Delta, had emerged. In the centuries that followed, Upper would conquer Lower Egypt, thus unifying the country and establishing Egypt of the Pharaohs. This unification took place under a king named Narmer (alternately given as Menes) in around 3,100 B.C.

When compared to the Fertile Crescent, Egypt was much better suited to breed a great civilization and all of the things that come with it, including: literature, religion, medicine, art, music, and science. While the Fertile Crescent was located on a flat floodplain between two irregular rivers (Tigris and Euphrates), Egypt was nestled in a valley bordered by deserts and bisected by a river that behaved like clockwork with its annual flood. With a reliable water source and protection from invaders on 3 sides, Egypt was the perfect location for history's first great civilization.

Now, onto the astronomy.

Even before the kingdom of Egypt was unified under Narmer, Egypt was a nation of farmers. Every year, snow in the Ethiopean highlands (where the Nile originates) causes the world's longest river to swell. In time, the flood reaches Egypt and inundates the land with water. While many would consider this a disaster, the Egyptians did not. Along with the water, the Nile flood also brought large deposits of nutrient-rich Nile mud. When the water receeded, the land would be covered with soil that was perfect for planting. Unlike other areas where there was always the risk of exhausting the soil, this problem was nonexistent in Egypt as the Nile would bring a fresh later of rich Nile mud each year. With this lucky chance, farming flourished in Egypt as it could nowhere else in terms of both productivity and yearly security.

'Nilometers' were used for measuring the height of the annual flood.
So, with this national reliance on farming, telling time was a most important business.

As far as we know, the Ancient Egyptians were the first people to recognize the 365 day year. For the Egyptians, a calendar allowed them to predict the time the Nile would flood. This way, the growing season could be determined from year to year. Besides the calendar, the Egyptians also noticed another astronomical portent of the seasons: every July, the Dog Star, Sirius, would appear to rise just ahead of the Sun. The helical rising of Sirius is where we get our “dog days of summer,” which mark the hottest period of the year.

On a more day-to-day scale, the Egyptians also developed a system for dividing up smaller units of time. The Egyptians divided the 365 day year into 12 lunar months of 30 days each. Also, the day was divided into 36 weeks of 10 days. Unfortunately for the Egyptian working man, the weekend was still only 2 days! Like other civilizations obsessed with even numbers, the last 5 days of the year were troublesome for the Egyptians. Unlike other cultures, the optimistic Egyptians took the last 5 days as a cause for celebration. Considered independent from the rest of the year, the extra 5 days were marked by festivals, feasting, and general revelry as the Egyptians celebrated the gods' birthdays at this time.

Unfortunately, as smart as the Egyptians were, they never picked up on (or did anything about) the fact that the solar year is actually 365 ¼ days long. As a result, after 4 years, the calendar would be a day off of what is was supposed to be. In longer time spans, the difference would become dramatic. In 100 years, the calendar would be almost a month off of where it should be. In all, it would take 1460 years for the calendar to cycle back to where it needed to be. So, with the calendar essentially useless most of the time, how could one go about telling the time of year?

Enter the Dog Star.

By an amazing coincidence, the helical rising of Sirius not only marked the start of the hottest days of summer, but also heralded the soon to come Nile flood. At its origin, the Nile would flood in spring. However, it would take several months for the flood to reach Egypt, with the delta over 4,100 miles downstream. So, come July, just like clockwork, the Nile would flood just as Sirius reemerged on the other side of the Sun as a morning star. With this lucky chance, the Egyptians were still able to tell time regardless of their flawed calendar. Because of this new cycle of flooding, planting, and harvesting, the Egyptians considered the first appearance of Sirius in the morning as the start of a new year. In Egyptian mythology, Sirius became associated with the goddess Isis, who is credited with creating the first mummy after she restored her slain husband, Osiris, to life after he was killed by his evil, envious brother, Seth. A more appropriate choice of stellar association was not possible as, just as Isis restored Osiris to life, the Nile flood, announced by Sirius, would restore Egypt to life via the life-giving waters.

Although it was only one star, the gods-stars association would grow much stronger as time progressed.

For the Ancient Egyptian, the greatest concern in this life was preparing for the afterlife. Although there were many different theologies in the early days of Egypt, they eventually coalesced together into a uniform religion that, at its start, was very stellar in nature.

The central idea of Egyptian religion was that, to guarantee an afterlife, the body needed to be preserved. Again, no one is sure where this idea came from but one idea is that, after burying the dead in the sand, the sand would dry out the body before bacteria could cause it to decay, thus preserving a shriveled, but very recognizable human form. In essence, these were naturally made mummies. In time, the sand would shift, revealing these preserved corpses. The living, upon seeing the bodies, may have assumed that, since the remains looked so life-like, that the individuals cheated death. What started as accidental preservation soon became an obsession and a central idea of Egyptian religion.

However, some people could see to that they were better prepared for the afterlife than being buried in the sand and hoping for the best. The pharaohs, considered living gods, had the wealth of Egypt at their disposal in order to ensure eternal life. With all the resources commanded, the pharaohs commanded elaborate tombs be built and techniques developed for the purpose of preserving the body. By the Fourth Dynasty in around 2,600 B.C., the art of mummification was essentially perfected and the tomb had evolved from a large pit in the sand lined with bricks and roofed over into the massive pyramids that people all over the world associate with Egypt to this very day.

For the pharaohs, all of this preparation still wasn't enough.

By the time of the pharaoh Khufu, the religious beliefs of the Egyptians, especially in regards to what happened to the king after he died, were very complex. For the pharaoh, there was no rest after death. By day, it was believed that the spirit of the king would join the sun god, Ra, in a solar boat that bore the Sun through the sky. With this association, the pharaoh's spirit would conquer death every day when
the Sun rose in the morning. After the Sun set, it was believed that the king would join the god Osiris, associated with the constellation Orion, in the night sky before being reborn with Ra in the morning. It was for this reason that two boats were buried with the pharaoh Khufu beside his Great Pyramid. However, the always prepared Egyptians had a backup plan in place just in case something went wrong somewhere.

An undeniable feat of engineering, the Great Pyramid is home to what have been termed “air shafts,” even though they don't all (at least today) extend to the exterior of the Great Pyramid. In the Great Pyramid, there are four such shafts, two extending from the king's chamber where Khufu was buried and two more from the incorrectly-named “queen's chamber,” which sits almost directly below the king's chamber. Ever since the pyramids were examined by historians, the purpose of these shafts remained an utter mystery, at least until the last few decades.

It was long known that the Ancient Egyptians placed a lot of emphasis in the stars in the battle to overcome death. However, it was not until 1960s that Alexander Badawy and Virginia Trimble  first postulated the idea that the air shafts in the Great Pyramid could have some stellar connection. The angle of the shafts known, the experiment was simply this: extend a line up to the sky and see if the shafts pointed at any stars that were important to the ancients. When this was done, no matches were found. However, thanks to computers, the sky's motion can be traced back through time and the phenomenon of precession to the point in time when the Great Pyramid was built. Result: each of the shafts was pointing at a star venerated by the Ancient Egyptians.

The South-facing shaft in the King's chamber was pointed at Alnitak, the lowest star in Orion's belt. As stated already, Orion was associated with Osiris, Egyptian god of the dead. The choice of this particular star could also be of more significance later.

The Southern shaft in the Queen's Chamber was pointed at Sirius, which was associated with Isis, goddess of among other things, rebirth.

The Great Pyramid's astronomical alignments.
The North-facing shafts were directed at alpha Draco/Thuban (King's chamber) and beta \Ursa Minor/Kocheb (Queen's Chamber). For the Ancient Egyptians, the circumpolar stars were known as the immortals for the simple reason that they never set and therefore, never “die” as they don't dip below the horizon. It was only natural that the immortality-desiring pharaohs would want to be associated with them. However, with these two particular stars, the Egyptians sought to do better for their King than merely send him in the right direction.

At the time the Great Pyramid was built, there was no North Star. Instead, all the stars seemed to revolve around an empty patch of sky located between, guess what, Thuban and Kocheb. Aa a result, the Egyptians pointed the air shafts at the two brightest stars near the location for the North celestial pole as it was at the time of construction. In addition,a the point of night when Thuban and Kocheb were directly vertical of each other, true North was indicated. Perhaps this is how the Egyptians orientated their pyramids so close to true North, with the Great Pyramid being less than 1/20th degree from perfection.

As good as this was, incorporating stellar alignments into the Pyramid's design, the whole Giza complex itself may have been modeled on the heavens.

Coincidence or design?Popularized by Robert Bauval in the 1994 book The Orion Mystery, one notion is that the Ancient Egyptians tried to copy the heavens on Earth via their pyramids. Whether this was intended or not is unknown (and probably never will be), but the coincidence is stunning. The Giza pyramids, three of them, consist of two large pyramids in a straight line with a smaller one slightly offset. Lookinga t the belt of Orion, the two lowest stars are of the same brightness but the highest one is dimmer and slightly out of line. While Bauvall and often co-writer Graham Hancock have taken their theories in a distinctly alternative history vein, the initial idea that the Giza pyramids were meant to copy the belt of Orion found supporters in the Egyptological community, including that of Egyptology legend I.E.S. Edwards, a former chief keeper of antiquities at the British Museum. Whether by coincidence or design, the theory does explain why the perfection-obsessed Egyptians would have made such a huge “error” in the layout of the Giza complex.

However, just after the Great Pyramid was built, the stellar orientation of the Egyptian religion started to wane. Yes, the stars were still important and astronomical scenes often decorated kings' burial chambers but the Egyptians would never go to the length they did with the Great Pyramid to incorporate the stars into the structure's design. Evidence for this fact comes in the names of Khufu's successors: Jedafra, Khafra, and Menkura. Notice all the kings' names end in “Ra” for the sun god, which the later kings would increasingly seek to associate themselves with.

The burial chamber of 5th dynasty pharaoh Unas.
As a last bit of pyramid-astronomy, consider the pyramid shape itself. Sure, when building in stone with the technology of the time, the only way to build extremely tall was with the pyramid shape as the design spreads the weight of every block onto the four below it, thus preventing collapse. However, why build perfectly, geometric pyramids at all? The first pyramids were stepped versions, simulating a staircase to heaven. So why spend time and effort building a true pyramid, which gives virtually no room for error? One theory is that the Egyptians saw the Zodiacal Light and thought of it as a light ramp to heaven for the king and thus wanted to replicate this launching pad on Earth.

Was the Zodiacal Light the inspiration for the pyramids?
After the Old Kingdom, which saw the construction of the Great Pyramid, collapsed in around 2,100 B.C., the stellar associations in Egyptian religion would decline as the Sun became ever more important. By the time of the New Kingdom (1550-1070B.C.), giant obelisks would populate the Egyptian skyline. According to some theories, the obelisks were built to simulate sun pillars in stone. However, at this time, the astronomical ceilings that adorned the burial chambers of the royals (and sometimes non-royals) reached their highest level of sophistication.

The burial chamber in the tomb of Seti I.

Obelisks: sun pillars in stone?
In 1279 B.C., the pharaoh of the pharaohs came to power in Ramesses II, better known as Ramesses the Great. Under his reign, it is widely regarded that Ancient Egypt reached the high-water mark of its 3000 year history. As befitting the greatest Egyptian, Ramesses created what can be considered the most spectacular architectural work (rivaling the pyramids, but in a different way): the Temples of Abu Simbel, located a the Southern border of Ancient Egypt.

The temple of Ramesses II at Abu Simbel
The inspiration for Mt. Rushmore, the facade of the larger of the two temples features four statues of Ramesses seated on his throne, each nearly 70 feet high. If that wasn't enough, the temple then extends nearly 200 feet into the mountain, revealing more chambers, colossal statues, and corridors before terminating in an inner chamber featuring the statues of four of Egypt's most important gods: Amun, Ra, Ptah, and Ramesses himself. However, on two days and two days only (February and October 20), the light from the rising Sun will penetrate all the way into the temple and illuminate three of the divinities, leaving the god of shadows, Ptah, out of the direct sunlight. Obviously, whatever the Egyptians were doing was being done with a purpose. According to legend, one of these dates marked the coronation day of Ramesses the Great.

However, the story of Abu Simbel wasn't done: in the 1960s with the building of the Aswan High Dam, the temples at Abu Simbel were soon to find themselves underwater if nothing was done to stop the rising water that was quickly becoming Lake Nasser. In a concerted effort sponsored by nations all over the world, UNESCO descended on the site, cut the temples (carved into the mountain) into blocks, and then moved the pieces up and out of the lake's reach before reassembling them like a giant puzzle. Through all this destruction and reconstruction, the alignment was preserved. In all, the project cost $80 billion in 1960s dollars.

The temples then and now

Despite all the moving, the alignment was preserved.
In summary, the Ancient Egyptian civilization fits the general pattern of ancient cultures that become interested in astronomy in that the initial motivation is practical (timekeeping to ensure successful farming) but the final product involves religion as supernatural powers increasingly find themselves assigned to the stars and the starts eventually find themselves transformed into deities. In all, the Egyptians have left us an incredible astronomical legacy in stone, that is, if you know what to look for.

A final word and warning . . .

When dealing with works about Ancient Egypt, especially those of a speculative nature, it is important to keep oneself firmly grounded in the facts. Yes, it is good to speculate on ancient mysteries and such speculation can often lead to truth, but, when it comes to Ancient Egypt in particular, authors have a thing for taking a perfectly plausible unknown and transforming it into something completely unrecognizable and highly implausible. Example: the Orion Mystery, which takes a perfectly logical idea supported by facts (the air shafts in the Great Pyramid being for religious purposes and even the idea that the Giza complex was built to simulate Orion's Belt), but then ruins it with assertions (the complex was built in 10,000 B.C. by survivors or a superior, lost civilization, probably Atlantis), both of which are without any solid evidence whatsoever.

As another example, consider that the pyramids have been:

1. Ancient mathematics coded in stone (play with numbers enough and you'll 'find' anything you want to find)
2. Repositories for lost ancient knowledge Iaparrently, someone checked out the entire library and forgot to bring it back)
3. The Biblical grain storehouses built by Joseph (never mind the fact that there is little internal space in the pyramids)
4. Prophecies in stone (prophecy is bunk in itself)
5. Built by survivors of Atlantis (pyramids have been dated to Ancient Egypt)
6. Built by aliens (there are quarry workers' notes on some on the blocks)
7. Power plants (if we're so confident of this 'fact,' why can't we fire it up again?)
8. Weapons of mass destruction (I'm not making this up!)

Yeah, right!

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