1 Astronomy of the Pyramids: Show Script Original show 2004 by Jennifer Moss Logan Updated version 2013 by Eddie Goldstein (with help from Alaina Reel, Matt Brownell, and Jess Wellington) 1/25/13
The ancient Egyptians built giant pyramids as tombs for the pharaohs. They were built exactly North-South-East-West. Why did they build them this way? And, how were they able to line them up so perfectly? The answer: they used the motions of the stars.
Script Notes Media Setup 1) Put foam wall sections off to the sides of the Space Screen. 2) Place merkhet, ropes, 2 stones, spinning plate and stick off to one side. 3) Microphone 4) Remote control 5) Lights ON 6) SELECT Astronomy of Pyramids Show 7) Make Exhibit Wide announcement
Hi Everybody. My name is XXXXX, and this is the Astronomy of the Pyramids show. 2 Script Notes Media Who knows what these are? (get answers) That’s right. They are pyramids. After all, this is the Astronomy of the Pyramids show.
Who knows where they are? (Giza Egypt) Actually, this is a modern picture taken from a plane. You can see the modern city of Giza in the background.
Who knows what they were used for? (Tombs for the Pharaohs)
OK, who here knew that the pyramids were built exactly North-South-East- West? That blue arrow points exactly North.
This show is about WHY the Egyptians wanted to line their pyramids up to the North. And, HOW they were able to do it – using the stars.
4000 years ago, during the time of the ancient Egyptians, these pyramids were the wonders of the world. So, let’s go back in time to see what was going on in the Egyptians’ minds. This was the Egyptian god, Ra. Ra was the god that fed the plants, that gave light to the Earth, that led people through the course of the day.
Can anybody here think of something in the sky that fits that bill?
(The Sun) That’s right. The Sun. To our way of thinking, the Sun REPRESENTS Ra. But not to the ancient Egyptians. When they saw the Sun going across the sky, they thought they were actually looking at Ra. 3 Script Notes Media The other big player in this story is Osiris. According to Egyptian mythology he was a pharaoh. His brother who was jealous of him chopped him up into pieces and spread them all over Egypt. Osiris’s wife (who was also his sister) was so upset that she collected all of the pieces, wrapped them up in linen, and he came back to life as the god of the underworld. He was the first Egyptian mummy. He is represented by this constellation. Does anybody know what we call this constellation? (Orion) When the Egyptians saw this, they thought they were looking at Osiris. Let’s watch Ra and Osiris going across the sky.
They go across the sky in an East-West path. MOVIE The Egyptians wanted to build their pyramids lined up with the paths of the gods so they could pick up some of the “energy,” or “vibes,” from the gods. That’s why they built them lined up exactly North-South-East-West.
OK. If you wanted to find out today which way is North, how would you do it?
(Compass, GPS, North Star) Those are all great. I used to look for the North Star. And, for us, today, that works. You can see how the pole of the Earth coincidently points toward the North Star. But it wasn’t that way during the time of the ancient Egyptians. 4 Script Notes Media Here’s why. Optional Spinning Plate
I’m going to spin this plate, just the way the Earth spins around. You can see that it holds it’s orientation even when I move the stick.
But, if I tilt the plate like this, just like the Earth is tilted, can you see how it moves? That is called precession. Believe it or not, the Earth also precesses. It takes 26,000 years to do it.
That means that while the Earth points to the North Star now, back in the time of the Egyptians, it didn’t. So they needed to come up with a different way to find North.
They probably came up with lots of ways to find North, but many of the methods basically boiled down to this one which I’m about to show you.
This represents where you are standing out to the horizon.
If a star rises exactly to the East, it will set exactly to the West.
So, if you were to connect a line between where it rises and where it sets, you will get an exact East-West line.
How many of you are with me? Great. But, if a different star rises in a different place, like “this much” away from East. . . it will set that “same amount” away from West. 5 Script Notes Media Then, if you connect where that star rises to where it sets, you will still get an exact East-West line.
Still with me?
That means that you can use any star, mark where it rises, mark where it sets, connect them up, and you get an exact East-West line. It doesn’t matter what star you use! That’s what we’re going to do. We’re going to pick a star, mark where it rises and sets, connect those points and get an East-West line.
Let’s pick a bright star to follow. Sirius is a good one. It’s bright and very near Orisis, so it’s easy to find.
OK, all we have to do is see where Sirius rises, run out to the horizon and put a flag MOVIE there, then wait until it sets, run out to the horizon and put a flag there, then take a rope, connect the two flags and we’ve got it. No problem.
Actually, there is a problem. First of all, when you run out to the horizon, the horizon isn’t there, it’s always farther off in the distance. And, you can’t even have someone else hold a flag out there and tell him to move left or right because you don’t have any phone to call him. How are you going to tell him which way to go.
We’ll have to come up with another way. What I am going to show you is just one of the many ways that the Egyptians might have used, but they all worked on basically the same principle. 6 Script Notes Media We’ll build a wall and sort of make our If you click into this movie own horizon. when the last one is in the daytime, it will look So, instead of marking where Sirius rises smoother. and sets on the real horizon, I’ll mark the spots on this stone horizon. Take out the two foam rubber PAUSED MOVIE walls and place them This is what the Egyptians called a touching, but sticking out merkhet. I’ll put it in the center of the from, the screen to make it circle and use it to sight along. look like a semi circle.
Put the merkhet in the center of the imaginary semi circle.
Then click to make the movie start again. OK. I need someone to help me out. The movie will automatically (Pick a volunteer and hand him or her a stop when rising Sirius lines stone.) up with the top of the wall. Please stand behind this wall (left) and move this stone back and forth for me PAUSED MOVIE while I line it up with Sirius. (You look through the merkhet towards Sirius. Have your volunteer move the stone on the wall until it lines up with Sirius.) 7 Script Notes Media Now, let’s wait until Sirius sets behind The movie will automatically the other side of the wall. I need another stop when setting Sirius lines helper. up with the top of the wall. (Pick another helper and have him or her line up a stone with the setting PAUSED MOVIE Sirius, according you your directions as you sight through the merkhet.)
We’ve marked where Sirius rises and sets. Now lets stretch a rope between those two spots. (Hand the loop of the rope with the red tape to the volunteer on the left. Hand the loop with the black tape to the volunteer on the right. Have them stretch the ropes over their stones and pull tight.)
These ropes make a perfect East-West line. How many of you are with me?
OK. Now that we have an East-West line, how do we make a North-South line? May need an extra click. The Egyptians knew that if you made a rope triangle with the sides 3-units, 4- units, and 5-units long, and you pulled it tight, it would automatically make a right triangle. They didn’t know why it worked. Pythagoras wouldn’t figure that out until more than 1500 years later. But, they knew that it worked.
(Have volunteers hold onto their loops while you take the third loop and pull it tightly to form a triangle. Hold your loop high so that the audience can see the triangle.)
So, this part of the rope must point exactly North-South.
(Thanks volunteers and send them back to their seats. Put the rope away.) 8 Script Notes Media So, that is our story of Astronomy of the Pyramids. They were built to line up with the paths of the gods across the skies. And the way that the Egyptians did it was by using the motions of the stars. The End
How to store the props on cart Foam walls Merkhet 2 stones Rope triangle Spinning plate and stick
Store the props behind planetarium stage
Questions and Answers
Did the pyramids align with magnetic North or polar North? Polar North. Since the pyramids are made to align with the paths of the stars and Sun, whose apparent movement is due to the rotation of the Earth, the result is that they are aligned with polar North.
Don’t the stars and Sun have different rising and setting points at different times of year? The Sun does rise at different points throughout the year, but stars do not. While the time of day/night when they rise and set changes, the location along the horizon (when seen from a set viewing location) does not change. This is why they would have used a star, rather than the Sun, to mark the artificial horizon.
Does precession play a part in this alignment of the pyramids? 9 Precession would not affect this method of finding East-West at all. Precession affects where in the sky the North (and South) pole points, rather than the actual axis of the Earth. Therefore, if you find the rising and setting points of a star now, then do the same thing in several thousand years, the two resulting East-West lines will be exactly parallel.
Tell me more about the theory that they used the right-angled triangle to find the North-South line. The Rhind Papyrus (1832 BCE) gives historians an insight into the role of geometry in ancient Egypt. The 3-4-5 triangle is one component of that. Today, we associate this triangle geometry with the Pythagorean theorem. Pythagorus, a Greek, came much later, and there is no evidence to suggest that the Egyptians understood this theorem. However, they did understand that a 3-4-5 triangle rendered a right angle at one corner. In addition to this written evidence, ropes with units marked by knots have been found. Some state that it would be too difficult to get the accuracy we observe using ropes, since it is difficult to mark units using knots, and the rope that would be needed to create a sufficiently sizeable triangle would be prone to stretching. However, this is one possible method that they may have used. See http://www.touregypt.net/featurestories/pyramidorientation.htm for more ideas.
How did the ancient Egyptians view the planets? The ancient Egyptians recognized that the 5 planets visible to the unaided eye plus the Sun and Moon moved across the sky compared to the stars. They saw these as deities, often in boats, crossing the sky.
Background materials (websites, videos, articles, links)
http://www.touregypt.net/featurestories/pyramidorientation.htm - excellent article on pyramid alignment, such as how they may have found the right angle, etc. http://www.touregypt.net/featurestories/numbers.htm http://php.math.unifi.it/archimede/archimede_NEW_inglese/curve/curve_giusti/prima.p hp?id=1