The Andes mountains in South America are a hotspot of astronomy today, but ancient peoples knew it was a great place for astronomy and lived their lives in tune with the night sky. Today we’ll learn all about what they knew, and how they mapped the movements of the stars and planets.
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Fraser Cain: Astronomy Cast, Episode 529 Ancient Astronomy in the Andes. Welcome to Astronomy Cast….space and journey through the cosmos, where we help you understand not only what we know but how we know what we know. I’m Fraser Cain, publisher of Universe Today. With me as always, Dr. Pamela Gay, a senior scientist for the Planetary Science Institute, and the director of Cosmo Quest. Hi Pamela, how are you doing?
Pamela Gay: I’m doing well, how are you doing?
Fraser Cain: Good. Now we are recording these episodes back to back, this week and next week’s episodes, so if something really exciting happens, we apologize in advance, we have – we are banking an episode. But you’re going to go somewhere interesting?
Pamela Gay: I am. Next week, I will be in Budapest, Hungary, a country I have never been to and I will be giving the opening keynote at Craft Conference, which is a software developers’ conference and I’m feeling totally overwhelmed, imposter syndrome is real. The individual, whose name I am not going to mispronounce, so I’m just gonna not say it, who developed the C++ programming language is going to be there.
Fraser Cain: Oh that’s amazing.
Pamela Gay: I’m not worthy.
Fraser Cain: Oh that’d be great. It’d be great to one programming nerd to another. It’ll be perfect.
Pamela Gay: It’s true.
Fraser Cain: All right, well let’s get into this week’s episode. So, the Andes Mountains in South America are a hotspot of astronomy today, but ancient peoples knew it was a great place for astronomy and lived their lives in tune with the night sky. Today, we’ll learn all about what they knew and how they mapped the movements of the stars and planets. So, two weeks ago we talked about the ancient astronomy of the American Southwest. That was great. Turns out, they weren’t the only ones watching the night sky. What was happening in South America over history?
Pamela Gay: Well, so, the first I want to do is – is try and paint a map of where everything was. So, we’ve talked about the Mayan a bunch before because the world did not end in 2012. And the Mayan were located in the Yucatan Peninsula. Then we – we also have the Aztecs, they’re more Mexico City. The Inca were along the Andes Mountains. In general, Peru is the country that is most associated with the Incans, but Chile is a place too, and they were located there as well. These artificial national boundaries we have today have nothing to do with the original cultural boundaries of these people.
So, the Andes Mountain – Mountains are the places that the Incas were located and what’s amazing is these are places where the sun was straight over head a couple of times a year, and that played a major role in how they viewed the sky.
Fraser Cain: That’s great. Right, I mean, we’re always so…we in the Northern Hemisphere – me – much farther from the equator than many people. I’m always just so used to the sun making this sad, pathetic journey across the southern sky. In the middle of winter, it shows up at like 9:00 a.m., 9:30 a.m., just pokes its head up and then heads back down at like 4:30. And then in the summer time it lasts a little longer. We get – it’s up at 5:00 and goes back down at like 10:00. But I can’t imagine what it’s like to stare straight up overhead and see the sun directly, where shadows just don’t exist.
Pamela Gay: And that was the thing. One of they key features of how they viewed the world they would build these giant nomen. These straight up and down sticks for lack of a better way to put it, and they would climb these sticks to get closer to the stars, which were in some cases identified as their deities. And beyond that, they also built these nomen in order to figure out different key dates of the year, and so depending on exactly where they were, it wasn’t going to be a solstice or an equinox when the sun was straight overhead. But, there were key days when you looked at those sticks and those sticks had absolutely no shadow and this is how they marked the passage of the year.
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Fraser Cain: Wow, and so what would they be – what would they be looking for apart from someone to tell them that if you climb a stick you’re not that much closer to the stars?
Pamela Gay: It was a noble idea. It wasn’t a valid idea but they tried.
Fraser Cain: But what could they then use, these moments of knowing they were at the…I mean, I guess it depends on where you’re going, and it depends on what latitude you’re at, what that means, but I guess anywhere as you go – anywhere between the tropic of Cancer and Capricorn you’ll have you moment when the star – when the sun is directly overhead.
Pamela Gay: Exactly, and this would tell them where they were in their local year and results would vary depending on where you were. And they coupled these nomen with also, a lot like we saw here in the American Southwest, they would create observatories where the shaman would stand in the exact right place and look out towards the horizon and look for the sun, the moon, generally the sun, to rise or set between specific pillars that would be built off on the distance.
Fraser Cain: Oh, cool.
Pamela Gay: And so, they were forever building things and for this we are mostly grateful. The problem and the reason it’s not completely grateful is the Spanish.
Fraser Cain: Right.
Pamela Gay: So, unfortunately, the Spanish Conquistadors tore down most of the easily accessible relics and people have had to try and piece together what was where and in some case figure out, ok if I follow this llama track, that has pottery shards all along the llama track, get far enough out, climb this hill, oh this is where there used to be sticks erected. And that’s kind of a miserable way to do archaeology, but this hasn’t stopped archaeologists, who may be the most self-hating of all scientists. And so they have tracked all over these mountain regions trying to piece together the cities, the alignments, and figure it out. Figure out how it was that they marked out their calendars.
Fraser Cain: So, then what do they think that they were doing based on the tiny clues that they found so far?
Pamela Gay: Well, it’s clear that they were trying to figure out when should we plant, when should we harvest, the normal things. Like so many societies of the world, they had celebrations for mid-summer and mid-winter and the equinoxes. And the Incan people found that their universe was one, continuous, united whole where the relationships with the stars, the relationships with even the dust in the Milky Way. The Incans were one of the only peoples, not the only, but one of the only peoples to have both star constellations, which they considered inanimate, and also dark constellations made out of the dust in Milky Way, which to them were animals that were very much alive and moving through the plane of the Milky Way.
So, I just love this idea that the stars were static and dead and the dust was alive with animals.
Fraser Cain: One of the places that I really wanna go, like as a child, I’ve wanted to go to Machu Picchu. And that’s an example of a place where astronomy is – was definitely happening there.
Pamela Gay: There was a vast solar observatory that has long been known about and it was somewhat in the heart of the city, it was where ritual sacrifices took place, so –
Fraser Cain: Of course.
Pamela Gay: – not so much a fan of that aspect. But we’re still exploring this vast city and it was found just back in 2012 that it appears there was also an astronomical observatory that was used to mark the rising and the setting of the various stars. And we still don’t exactly understand how everything fed together. I – we know that other cultures, for instance the Greeks, saw the rising of Sirius, the dog star summer as adding heat to the hottest month of the year.
We’ve lost too much of the culture of the Incas. It was purposefully eradicated, purposefully killed out, and so we may never know, but at least by finding these places, by doing laser re-creations of them in software so that we can explore all possible alignments, it’s starting to give us hints of what’s possible. And this ability to use archaeological maps in combination with planetarium software is something that was first done, actually, for the Inca Nazca lines and for Stonehenge. And while Stonehenge was really good at offering up clues as to why it was there, the Nazca lines are more annoying.
Fraser Cain: We, as science explainers, have definitely run into the Nazca lines and there’s a lot of nonsense out there, so – but they’re a real thing –
Pamela Gay: Yes.
Fraser Cain: – And they’re actually pretty amazing. What do scientists think they probably are, like if you went there right now, what would you see?
Pamela Gay: Well, so what we’d see is there’s three different kinds of Nazca lines. There are ones that are made subtractively. So, the Nazca lines are out in the Atacama Desert. The most prominent, the most well known ones are in the vicinity of Nazca, Peru. There’s also lines on the Chilean side of the Andes and the Atacama Desert. And these two suites of lines are made either by people removing the darkened topsoil that has been made a rusty color through interactions with solar UV light. But, there’s like no rain there, no rain pretty much at all, a couple millimeters a year, maybe. And, by going through and removing this UV altered soil, they can reveal the white stuff underneath.
And what is cool to me is this isn’t all that different from how we’re able to see the trails of dust devils on Mars, where it reveals the subsurface soil that’s a different color. Now it’s a really subtle effect, and in some places rather than simply stripping off the surface material, they also gathered rocks and pebbles and added that on top of the surface, and in some places they did both. They scraped off the topsoil and piled rocks and these lines are kilometers and kilometers across, and you can’t really figure out what the heck it is that’s out there until you fly over it. And in fact, these Nazca lines weren’t even known to modern peoples until the 1930’s when regular commercial air flights started to take place.
Fraser Cain: That’s such a crazy discovery that you would be flying overhead and see some recognizable shape that people had been crossing for all their lives as they moved around the desert and never had an idea of what it was. And finally, we get some perspective. So, I mean if your average person would have no sense of what it is they were looking at, it must have required tremendous math for them to figure out how to lay down these lines in a way that was recognizable by who? By the gods?
Pamela Gay: And this is where you start to get all the crazy internet rabbit holes that, unfortunately, have far more YouTube hits than we do.
Fraser Cain: Yeah, exactly, yeah.
Pamela Gay: So there –
Fraser Cain: Yeah, go ahead, search for Nazca lines on YouTube. I dare you.
Pamela Gay: On the more benevolent side of we don’t think this is true, are the theories that they actually had hot air balloon technology. And people have been able to create hot air balloons out of things that the Incas are known to have had, but, there’s like, no records of hot air balloons and it kind of seems like that’s the thing there would be records of. So, that one falls under the category of mostly harmless, could be true, probably isn’t. As we go down towards the crazier and crazier ideas, we start to hit the aliens have visited and these were built in worship of the aliens, or built by the aliens, built with the aliens. I inadvertently came across an article where one of the people who’d been preserved in the glaciers was viewed as being an alien instead of a human.
Fraser Cain: Right.
Pamela Gay: Yeah, there’s lots of crazy, don’t go there people, don’t go there.
Fraser Cain: But you can kind of imagine the thought process right, which is that they’re saying okay we think the stars are – the gods live among the stars. And so they make an estimate. You know they climb the top of a mountain and the stars don’t get any closer. They go to the bottom of a valley and the stars don’t seem to get any closer. So, they know that the stars are really far away and so if they want to show their dedication and devotion to the gods they want the – and they know how far away you can see something, so they figured we would have to make something really big, in a place that was really flat as our big easel.
And then they did the math to figure out how to map some small drawing that they’d made to something that was very large so that it could be visible to really far off.
Pamela Gay: And we’re not even sure if that’s really the reason that that was done. More recent studies are starting to explore the idea that maybe, yeah; the giant spider in the desert probably had ceremonial reasons. But, these lines come in a variety of different patterns ranging from geometric to that’s an animal, that’s a spider, that’s a monkey, that’s an eagle. And some of these shapes seem to be indicating over here is where you can find water, over there is where you can graze. And so, there may have been a joint ceremonial and informational use to having these Nazca lines.
And this joint, everything is united is very consistent with what we know of the Incan people, who did see it all as one continuum of we’re all united. Now have there been, falling down the rabbit hole again, some interesting articles that probably aren’t true, but since we can’t go back and interrogate the people who built these lines hundreds to thousands of years ago, or hundreds to over a thousand years ago, we don’t know. So, there is one researcher who feels that the great spider that is spotted out there is actually a projection of the constellation of Orion onto the surface of the planet as viewed by a very different culture.
And so there are lots of attempts to try and unite the, is this pointing to water, is this pointing to grazing, is this just showing off? We see you up there stars that make Orion or make a spider.
Fraser Cain: Right. Yeah.
Pamela Gay: Pick your translation.
Fraser Cain: Right, so, admire or devotions gods. We built pictures that you can see…from space. Or – or they serve some way to memorize – memorialize the constellations as they understood them. It’s a fascinating mystery.
Pamela Gay: And the Incan culture was huge. It spanned modern day Peru, parts of modern day Chile. And there were vast trading paths for llama and these Nazca lines weren’t associated with any ancient cities that we can tell, but they were along the llama routes between the different cities that did exist. So, part of me also wonders how much of it was this was just part of what people did as they traveled back and forth across this horrifying desert. Was this a hello god, please don’t kill me, I’m gonna make this – this pattern a little bit bigger. What – what exactly was the purpose we can’t ever really answer and that’s part of the beauty of it.
Fraser Cain: That’s really cool. Any other regions that are located in the area that have some interesting astronomical significance?
Pamela Gay: Well, we’re going to get the most of that astronomical significance in our next episode where we hit on all the different observatories. But I think with this the one thing we probably skipped over way too fast because I was excited about getting to the Nazca lines –
Fraser Cain: Yeah, me too.
Pamela Gay: – was how they used these nomen indicators and the mythology associated with this is fabulous to think about. So, they were erecting sticks, it’s what they did. And in their tradition, August was some of the most important time of the year because here, Southern Hemisphere, you do your planting in August. And because they weren’t exactly on the equator, August was when the sun came along and sat squarely on the top of their poles and this is how they viewed it. They actually viewed harvest time as when the land parted and the farmers planted their seed in the earth, take that where you will, that’s what they did, and at this point the sun has paused directly overhead to, well, fertilize the land.
Take that also how you will. And so you have this – this idea of the sun sitting atop the stick, and there were some rather crude ways that early archaeologists put this, which I am not going to repeat, but I will let your imaginations go there. Now, in addition to this day when the sun was straight overhead, they also held ceremonies for when the sun was at its anti-zenith, which is something we haven’t really seen in other cultures. Now again, unlike most of the cultures we have looked at, their sun was straight overhead. Greeks didn’t have that going for them. The Americas didn’t have that going for them, here in North America where we have the Navajo and Zuni and so many other histories.
But the Inca had the sun straight overhead, and so instead of having their celebration for winter solstice, they did have their celebration for winter solstice, they also worried about that exact moment when the sun was directly beneath their feet. Now, you can see exactly when the sun is straight overhead. You put up a stick, you look for the shadow to go away, that’s easy. Now they also figure out when the rising and setting points, where they were on the sky. And it turns out that you can use geometry to figure out based on the sunrise and sunset positions, exactly where the anti-sun is.
So, specifically when the sunset beams in the morning hit going straight across the land, the sun – sorry, the sunrise beams go straight across the land to hit the sunset point for the zenith that was when you were looking at the anti-zenith sun.
Fraser Cain: Well hold on, so is the anti-zenith sun then in the middle of winter?
Or is it…
Pamela Gay: It’s in the fall. So, if you have zenith occurring in August for planting…
Fraser Cain: Right.
Pamela Gay: Then you’re going to have anti-zenith in spring and they have a celebration for it.
Fraser Cain: Is it – so is it – I’m just trying to imagine the geometry. Is it dependent on how far away you are from the equator? Because…
Pamela Gay: Yes.
Fraser Cain: Right, okay. So, if you are right at the Tropic of Capricorn or Cancer, then you’re gonna get the sun going directly overhead, is that at the solstice?
Pamela Gay: Very close together, so they will actually both be in the spring.
Fraser Cain: Right, but if you’re farther away, then you’re gonna have this moment as the sun is directly overhead and then a couple of months later, you’re gonna have this moment where the sun is directly under head.
Pamela Gay: Right.
Fraser Cain: Right, I see, now.
Pamela Gay: And I misspoke, it isn’t exactly spring and fall. That is a conceit of making the geometry far too easy in my head for a moment. So, if you’re directly off the equator – so a few days after the equinox when the sun is directly over the equator, you’ll have the sun directly over your head. You then wait, wait, wait, wait, while it travels north. It goes through its extreme, travels south, south, south, south, south, so it’s right before that next equinox. So, here you do have fall and spring. But, if you’re right next to the equinox position, it might be like three days apart if you’re right next –
Fraser Cain: Right.
Pamela Gay: – not equinox, solstice position. If you’re right next to that solstice position, it’s just gonna be a few days apart and it’s both going to be in the same season.
Fraser Cain: Right and the point being that if you appreciate the sun and celebrate it’s directly overhead then they were most nervous about it having the least amount of sun. The point where it was directly, or the most anti-sun. I just like that idea, right?
Pamela Gay: Well it’s anti – it’s not least sun, it’s anti-sun –
Fraser Cain: It’s anti-sun, yeah.
Pamela Gay: – because least sun is other side of the equator doing other things.
Fraser Cain: It is directly below your feet.
Pamela Gay: Yeah.
Fraser Cain: It is as below your feet as the sun can be, which is such a clever idea. I like that.
Pamela Gay: And it’s always fascinating to see how different cultures connected with the sky in both useful and un-useful ways. I don’t see how anti-sun is necessarily a useful thing, but for them it was a thing. And their use of nomen though, that is a thing to celebrate about being near the equator. I’m just, like, enthralled with this concept. So, yeah, they had sun temples that were places where people got sacrificed. They had astronomic…
Fraser Cain: Right. Yeah, you need to know the exact right time to sacrifice somebody.
Pamela Gay: They had astronomical observatories for observing the sky. They had nomen for observing the changing of the dates and for literally climbing to get closer to the gods. And for them it was all one, it was all united.
Fraser Cain: Wow. All right. So, next week, which for us is gonna be in about four minutes, we will be talking about the modern astronomy in the region, which is of course, out of control. It’s crazy.
Pamela Gay: That’s an understatement, oh dear God.
Fraser Cain: Yeah, yeah, so we will get to that in a second, but before we wrap up today’s episode, do you have some names to celebrate?
Pamela Gay: I do, I do indeed. Today we would like to thank for their support over on Patreon.com/astronomycast, you are the people who keep us going month after month and let us pay Susie. I’m saying thank you for Susie and all of us too. So thanks to Elad Avron, James Platt, Nate Detwiler, Marek Vydareny, John Drake, Jeff Collins, Silvan Wespi, Thomas Sepstrup, Richard Riviera, Greg Thorwald, Frank Trippin, Bill, Hamilton, Jim Smith, Kjartan Saevre, Helge Bjorhaug, Joseph Hoyd, Dana Nourie, Emily Patterson, Les Howard, Corey Devali, Jos Cunningham, Robert Palsma, Laura Kittleson, TheGreatNothing, David Truog, Brian Cagle, Andrew Poelstra, Ramji Enamuthu, I’m so sorry, Burry Gowan, and Jordan Young, and I adore all of you and I apologize for everyone who’s name I continue to mispronounce, with gratitude, month after month after month. Thank you for making us possible.
Fraser Cain: Thank you so much, we’ll see you all next week.
Pamela Gay: Bye-bye.
Announcer: Thank you for listening to Astronomy Cast a non-profit resource provided by the Planetary Science Institute, Fraser Cain, and Dr. Pamela Gay. You can find show notes and transcripts for every episode at Astronomy Cast. You can email us at firstname.lastname@example.org, tweet us @Astronomycast, like us on Facebook, and watch us on YouTube. We record our show live on YouTube every Friday at 3:00 P.M. Eastern, 12:00 P.M. Pacific, or 1900 UTC. The intro music was provided by David Joseph Wesley. The outro music was by Travis Sorel and the show was edited by Susie Murph.
Duration: 30 minutes