Ep. 528: Modern Astronomy of the American Southwest

Posted on Apr 26, 2019 in Astronomy, Doing Astronomy, podcast | 0 comments

Last week we talked about the ancient astronomy of the American Southwest. But this is actually Pamela’s stomping grounds, and she’s spent many a night perched atop mountains in this region staring in the night sky with gigantic telescopes. How does astronomy get done in this region today?

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Show Notes

Kitt Peak National Observatory – National Optical Astronomy Observatory

McDonald Observatory

Lowell Observatory


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Fraser:                         Astronomy Cast Episode 527: Astronomy of the American Southwest. Welcome to Astronomy Cast, your weekly facts-based journey through the cosmos, where we help you understand not only what we know, but how we know what we know.

I’m Professor Cain, publisher of Universe Today. With me, as always, Dr. Pamela Gay, a senior scientist for the Planetary Science Institute and the director of CosmoQuest. Hey, Pamela how you doing?

Dr. Gay:                      I’m doing well. How are you doing Fraser?

Fraser:                         Really good, it’s been a nice relaxing week so far, actually. It’s been good. Some follow-up stories, you know the Beresheet Lander crashed, but now Beresheet 2 is go. The Falcon Heavy landed perfectly, except it didn’t, the core booster fell over in the high seas and broke in half and half of it –

Dr. Gay:                      I didn’t know that.

Fraser:                         – was returned to Poseidon. You didn’t know that?

Dr. Gay:                      No.

Fraser:                         No. Yeah, so it landed and then fell over in the high – because the Octagrabber can’t grab the core booster of a Falcon Heavy. And so, yeah, it fell over and the top crunched off and went to Davey Jones’ locker. –

Dr. Gay:                      The need an Octagrabber massive edition.

Fraser:                         Yeah, an Octagrabber heavy, yeah.

Dr. Gay:                      Yeah, yeah.

Fraser:                         And, of course, we’ve still just been feasting on black hole news. So, it’s been – but it’s been a lot more chill, but it’s been good. Let’s just say I was very burnt out on space news last week, all excited about space news again this week.

Dr. Gay:                      Yesterday and today have been like story after story after story. And what I loved is today there was a theme of when asteroids invade your solar system. And it was a pleasing theme; it was a really pleasing theme. Yeah.

Fraser:                         Ancient peoples had no light pollution and they knew the night skies very well. In fact, they depended on them to know when to plant, when to harvest.

Today Pamela talks about the archaeoastronomical sites of the American Southwest, which coincidentally is a place you are going to be traveling to relatively soon.

Dr. Gay:                      It is true. Next August I am going to leading an astro tour through the American Southwest, departing from Tucson, going to places still being determined, but will include national parks and observatories, and ending it all in Las Vegas.

Now, we aren’t going to get to visit a lot of the archeological sites that I’m thinking today, but the reason that I’m leading that tour is because that’s the part of the country where I spent my summers growing up, it’s where my grandparents are, it’s where I went to graduate school, it’s where I did a summer REU as an undergrad.

And so when I picked the topic for today, it was basically like, “Okay, the news is heavy, I wanna pick something that will bring me joy to read,” and I kind of –

Fraser:                         I know exactly how this went down. You were looking at sites that you were going to be going and thinking about it and then just nerded out and went down a rabbit hole of cool historical archeological sites in the American Southwest.

Dr. Gay:                      Yeah, no that – so, actually I was playing Ticket to Ride with Keeper of Maps and Paramore, going, I have no idea what to talk about, I have no – I am out of ideas. And it was out of me bemoaning how I was out of ideas as I faced the week’s world news, that I was like, what if? And it was like archeology, let’s talk about archeology, let’s talk about things from before the expletive hit the fan. So, yeah, yeah.

Fraser:                         Yeah. So, but I mean the irony, of course, is that the places you’re gonna be talking about are not places you’re gonna be going on your astro tour, I think that’s the point –

Dr. Gay:                      Exactly.

Fraser:                         – is that this is pure Pamela rabbit hole, this is you finding something and nerding out about it for our benefit.

Dr. Gay:                      It’s true and this is going to be part of a series and we are going to talk next week most likely about the modern astronomy being done in the American Southwest. So, today we start with the beginning times and next week we’re gonna talk about how we’re learning about the end times.

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Fraser:                         So, where do you wanna start? Which peoples, which sites, which monuments?

Dr. Gay:                      Well, it probably makes sense to start at the beginning. And the beginning is Chaco Canyon as far as the Archeology goes. This is the place of the Anasazi people. If you read a lot of Neil Gaiman, this is the peoples where Coyote originated in the stories.

And the Anasazi went on to fragment into the Pueblo tribes that include the Zuni, the Hopi, and many others. Now, the reason that we’re starting with the Anasazi isn’t just that they’re the old people; they’re the first ones is how they’re often referred to.

But they also left us amazing archeological records of how they traced the seasons, the stars, in Chaco Canyon, which is a UNESCO World Heritage Site, and it’s also one of the very few sites in the world where the supernova of 1054 is believed to have been recorded.

Fraser:                         I just surprised Pamela with an actual picture of the places she’s describing, so for those listening there’s a stunned silence there for a moment. But this is what the audience is seeing as well. Is this what you’re talking about, Pamela?

Dr. Gay:                      Why, yes. Yes, it is.

Fraser:                         Okay, all right. So, what kind of features are at this place?

Dr. Gay:                      So, the 1054 supernova is recorded – at least this is one of the explanations. What is seen is there’s a cliff-face, rockface, that has a handprint, a crescent moon with the points facing down towards the horizon, which indicates it’s near the horizon. As the moon comes up, it rotates, and so you can actually tell what phase of the moon you’re looking at. Based on how it’s oriented, it always has the bright side pointed towards the sun. And then it shows a bright many-pointed star next to it.

And while the mundane explanation of what this is says, oh, it’s just the crescent moon, the planet Venus, and a handprint. What is also looked at is perhaps this is one of the very few examples of the 1054 supernova being recorded.

This particular supernova went on to become our ever-beloved Crab Nebula. And for whatever reason, even though it shined many times brighter than Venus and stayed put, unlike Venus, it wasn’t noted by Europeans that we know of.

There is like a known recording of it in Arabic literature. There are a bunch of notices about it in Japanese literature and Chinese literature. And part of this is explained as, well, the Europeans were more closely tied to dark ages and Christianity at that particular moment in time and wouldn’t have seen the sky the same way, whereas the Chinese and the Japanese were using it as recordkeeping. They were actually careful recorders of the sky.

And similarly, we had a – we use the sky for day to day stuff, culture, in the American Southwest, where one of the ways that they figured out their calendar was to stand on specific rocks and look for the sun to rise and set, aligned with specific places. And they also had sun towers scattered throughout the American Southwest.

Fraser:                         That’s cool. So, what’s a sun tower?

Dr. Gay:                      It’s a cute little squat tower, meter or so wide, couple of meters tall. And they typically have an ability to get in and out. You need a door. But once you’re inside, there are specific windows that are lined up to capture the sunrise or sunset on specific dates, lined up with specific objects on the wall. So, these would be designed to conform to the local latitude and longitudes, the local geography. So, these were built by someone who was like, okay, I have to put the window here and on this day the sunlight is gonna shine through. Okay, quickly record it on the wall. Okay, I’m gonna put a monument here.

And once these were created, you could sort out a calendar based on the extremes of the summer and winter positions of the sun and by looking at how the sunlight shined in through these windows and where it hit the wall, you could build a calendar.

Fraser:                         That is really cool. It’s kind of like – well, I’m sort of thinking Manhattanhenge.

Dr. Gay:                      Yes.

Fraser:                         But after the fact, right? So, if they had actually designed Manhattan for the perfect day, waited for the sun to come straight down some streets and then built a whole city around it, then that would be the same thing. But as opposed to an interesting coincidence, where the sun happened to come down some streets on Manhattan on one day of a year at a certain time.

And so like what would they use something like this for, apart from just feeling really proud of their ability to predict the movements of the sun?

Dr. Gay:                      Well, calendars, in general, are a useful thing and the moon is an annoying thing. One of the things that was quickly realized by academics who tried to interact with what remained of the indigenous peoples of North America was they have a very different relationship with time than Europeans do. And for many of the peoples of North America, the calendar would be divided into two chunks. And here this is particularly true of the Pueblo nations that descended from the Anasazi.

And with the Pueblo nations, you might have half the year that have very poetic names that are tied to things like this is the moon when the snow breaks the branches off the tree, this is the moon when the eagles fly. And each tribe had their own names, but what typically occurs, you’d have half the moons of the year that have these amazing specific glorious names. And then the other half of the year, it’s like colors. And this is in part because directions had a sacred place in the Pueblo peoples. And you’d have the six sacred directions, those would be given six months. And then you had the other months of the year, which were treated more fluidly by being tied to, okay, let’s look outside and see what’s going on. Okay, now we know the name of this moon. And the reason that you needed to have that fluidity is you can’t divide the number of moons evenly into the length of the year.

Fraser:                         Right. Yeah, it’s like 29 ½ days is the length from full moon to full moon. That’s – and so you just –

Dr. Gay:                      It’s 12 moons and 11 days per year, essentially.

Fraser:                         Right. And so you can’t get –

Dr. Gay:                      And if you –

Fraser:                         You can’t get them to line up nicely.

Dr. Gay:                      No, no.

Fraser:                         That would have been so convenient.

Dr. Gay:                      And the way they get around not having this work is by paying attention to part of the year very carefully. And in some of the most northern latitudes, which we’re not discussing today, other than this bit, they didn’t even bother with some segments of the year. It’s like, okay, we’ve got no moon, we’ve got no sun, we’re going to suffer.

And then once you have that return of the sun, once you start to see the special days of the year coming, then you start noting, okay, if I stand on this rock and I look out at that ridgeline and I note the rising point of the sun as it migrates across the horizon, this tells me the special days of the year.

And by looking for the first moon after the sun, that allows you to keep a better calendar. And there’s actually some sacred ceremonies that are supposed to coincide with horrible to figure out things, like the full moon closest to winter solstice, which is one of the hardest things to observe because you have these short days, you have miserable weather. The probability that your ability to observe is going to be, well, blocked by clouds is great.

And there are records of people essentially making fun of the sun priest in their village because they got it wrong. And so planting was off and these poor individuals got blamed.

Fraser:                         Right.

Dr. Gay:                      Now, here in Illinois with my modern European calendar, I know I don’t plant anything before May 1.

Fraser:                         Mm-hmm, yep.

Dr. Gay:                      And I’m sure you have something similar there in Vancouver.

Fraser:                         Yep, [inaudible] [00:17:36] long weekend. Oh, you don’t have it. Middle of May. We don’t plant anything.

Dr. Gay:                      And in Massachusetts it was Memorial Day Weekend because it’s even colder there. Well, we tie things to certain dates. They didn’t quite have the capacity to do that, so they had to use a combination of the sun and the moon to get an ancestrally determined repeated experience, this is when you should plant.

And when the priest got it wrong, well, you know who [inaudible].

Fraser:                         Right, yeah. Sorry, we call it Victoria Day. And that’s on May 20th and that is, of course, to celebrate Queen Victoria, who is very near and dear to our hearts here in Canada.

Dr. Gay:                      It’s a thing.

Fraser:                         And it really is a thing.

Dr. Gay:                      It’s a thing.

Fraser:                         Now, we happen to have a Victoria as a city here in Vancouver Island, but that’s not what it’s for. But, yeah. I mean when you look at Chaco Canyon, it is just this stunning site, this enormous sort of half circle with these embedded circles inside of it. How much of that is astronomy-related and how much of that is just living spaces and various other celebrations and other community events?

Dr. Gay:                      Well, based on knowing that today’s multiple Pueblo nations are descended from the peoples of Chaco Canyon, the modern peoples have their great Earth lodges that have four massive pillars that mark out the cardinal directions, north, south, east, and west. And they suspend a round roof that is meant to be a reflection of our sky. And it is off of these cardinal points, it is off of the great sphere of the sky, hemisphere is what we see, that they build in their architecture.

The great circles, some of them are called kivas; they were only open to men. These were the meeting places, the religious centers. But the Earth lodge was a place for everyone that was also round. And so we see these shapes that come up over and over and it is a reflection of seeing themselves as being tied to the stars, tied to the seasons, tied to the Earth and the sun. And it was all one thing within their philosophy and their culture.

Now, we have lost a lot of the details of this, unfortunately. The majority of our understanding comes from the Zuni people. They were geographically hard to get to by the Spanish. So, unlike many of the other Pueblo peoples, such as the peoples of Taos, which is now basically a ski resort. The Zuni people were isolated. They’ve managed to maintain many of their traditions across the centuries. So, there is wiggle room in our understanding.

Now, we see, though, this ability to see the architecture get reflected in multiple places, from Chaco Canyon, for reasons that aren’t really well-understood, Chaco Canyon grew and grew and grew, became an amazing metropolitan city. But for some reason around 1150 it pretty much emptied out. One of the leading theories for why it emptied out was a massive drought. These things happen in that part of the world. And there was a simultaneous rise of the peoples of Mesa Verde, who were also the Anasazi people, but that was a later city up in Colorado that grew up, growing inside the canyon walls again.

And, again, in Mesa Verde, you see these same aligning your architecture so that sunlight shining through walls can mark the seasons. Choco Canyon sun dagger is the most famous of these, but we see this idea of sunlight shining through small spaces to eliminate symbols, getting repeated over and over throughout the architecture of the America Southwest.

Fraser:                         And that’s got to be where, for example, the Harrison Ford raiding the lost ark had opened up a door using sunlight. Or it was a crystal, that’s right. And things had to line up perfectly on the right date. I’m sure they got the inspiration from something like that.

Dr. Gay:                      And it was a common way of keeping track of calendars. We saw it similarly done in Egyptian architecture, mirrored again throughout Greek. We need more understanding of what was going on throughout the rest of the Middle East and Saudi Arabia is finally allowing archeologists in, so hopefully we’ll get more understanding of that part of the world.

The sun dagger is perhaps the best case of, oh, those rocks are doing something useful. In the British Isles, they moved rocks to create solar alignments. In Chaco Canyon, there is a set of three rocks that align just right to create a thin dagger of light that passes through the rocks and onto a wall behind the rocks. And on this wall there’s carved a beautiful spiral pattern. And on the equinoxes, the sun dagger pierces the center of that pattern. And on the solstices, it hits the two extremes, the bottom and top of that sun – of that spiral pattern.

So, the motion of the dagger of light passing between these three stones that appear to be a natural formation was taken advantage of –

Fraser:                         Right.

Dr. Gay:                      – to create a calendar.

Fraser:                         That is just – that’s amazing, like a natural sundial.

Dr. Gay:                      Well, and just think about all the study that would go into getting that perfect. Some human being, basically, watched the stone and did whatever the historic equivalent of penciling it in was.

Fraser:                         Right.

Dr. Gay:                      Until they knew exactly where it would hit on the equinoxes, until they knew exactly where it would hit on the solstices, and then carved into the rock. You only get one chance to do that right.

Fraser:                         Right. Yeah, take a couple of years, make sure that you measure twice before you carve once. So, I mean were there – I mean this is just one location, but this same thing was repeated on a lot of these sites. They had like mini versions of the same kind of facility, right? So, your local clock.

Dr. Gay:                      And this is where we go back to the sun towers and also the difference in how they paid attention to time. The Pueblo people, the Hopis, the Zunis, they didn’t think the same way about noon and 8:00 p.m.. And so there’s this sacredness to certain days, but not a sacredness to time. And there was also the, yeah, we fully acknowledge sometimes it’s 12, sometimes it’s 13 solar cycles, so we’re just gonna, well, look outside and see what’s going on.

But they did rely on that sun and this is where we go from that old, old sun dagger scene in Chaco Canyon to instead having the sun towers. Now, beyond just noticing the sun, they also watched the constellations. And while their understanding of many of the different constellations, what they were, differed from the European ways of looking at the constellations, although everyone seems to have seen Scorpio as a scorpion. No matter who you were, it was a scorpion. But beyond some of those exceptions, they were picking out many of the same stars that we pick out. And this also went into their understanding of the seasons.

And unlike many other cultures, they took these constellations. And just like we do today with Think Geek, they turned it into their day-to-day food storage items. So, you can find crocs that had the constellation Orion in the lid.

Fraser:                         Oh, really?

Dr. Gay:                      Yeah.

Fraser:                         So, they would – and so like that’s when you open it, when you can see Orion, that’s when you open this lid and eat the food?

Dr. Gay:                      Well, I don’t know if that’s the case.

Fraser:                         Okay.

Dr. Gay:                      We can’t know that.

Fraser:                         I don’t know.

Dr. Gay:                      We simply know there are food containers that had constellations on the lid.

Fraser:                         That’s my theory. If you see Orion, then it’s –

Dr. Gay:                      Well, does that make sense.

Fraser:                         Then it’s probably time to eat this.

Dr. Gay:                      Yeah, so they knew their stars and it got tied into the lore. And it also got tied into the lore, the not knowing which moon it was. And this is a fabulous combination of they knew on this date the sun would set behind that place on the ridge. They knew in this season this constellation rises and is high and it was passed through the oral traditions.

But there’s also a fabulous Zuni tale of the person who was murdered because they said, well, the current season is, and they named the moon. And the person responded, no, it’s the moon of the eagle flying, you moron. There was an eagle flying behind you, except they said this in their ancient language. And the person turned around to look at the eagle and got their throat slashed. And the murdered responded, don’t you know there are no eagles in this season?

And so it was widely acknowledged that the season moons were fluid, but the sun and the constellations were set.

Fraser:                         That’s awesome and horrible. But that is the nature –

Dr. Gay:                      And it shows us –

Fraser:                         – of a bunch of these legends.

Dr. Gay:                      Humans are humans throughout all time. And one of my personal greatest sadnesses is there were amazing civilizations all across the United States that just died off horribly after the Spanish and Dutch began exploring, simply because European diseases –

Fraser:                         Yeah, they brought their little friends.

Dr. Gay:                      Yeah. So, the Mississippian people who lived where I live now went from having one of the largest cities in the world to just not existing anymore. So, there’s so much that we can’t know and this is why we’re so lucky that the Zuni were so isolated.

Fraser:                         Yeah. Were there anymore sites, anymore interesting features that you wanted to mention in the last couple of minutes?

Dr. Gay:                      I think this is one of the main sets of things for now. We will be going into discussing all of the telescopes that got built. They also, I should say, used the constellations on rattles that eventually got turned into the shakers used in mariachi bands. The original ones used by the native peoples also had constellations on them, so they used it on musical instruments that were ceremonial in many respects as well.

So, the takeaway from all of this is that the native peoples of the American Southwest had this fabulous time is fluid, the moon misbehaves, the sun is solid, we can trust its rising and setting to determine when we should plant.

And stars are cool, so put constellations on your musical instruments, on your food gourds. And we are part of our universe and we build our largest permanent settlements to have this earth lodge that reflects the cardinal points in the sky and its architecture. And I wish we built more architecture that incorporated, well, our universe into its design.

Fraser:                         That’s a great idea. That sort of – I mean we definitely think about that a bit here in Canada. When we build a house, you want a south facing whenever you – you know you have part of it face the south so that you can get some sunlight because it’s cold and wet, since you want to maximize the chances.

Dr. Gay:                      Yeah.

Fraser:                         And so you do think about the larger sort of facing, but you don’t necessarily – I would love to have a house with some feature that on one day of the year you get this shaft of sunlight or something that perfectly goes to some other location. That would be so cool. And so I’m gonna add that to my blueprint for my future house.

Dr. Gay:                      To let the audience in on one of my happy little no longer secrets, part of the reason that my recliner is placed where it is placed is because on the most miserable winter mornings in January, the sunlight comes through my office window, shines through the fish tank, makes all the plants start bubbling oxygen, and casts rainbows all over the walls. So, I organized my office furniture to maximize winter sunlight.

Fraser:                         That’s incredible. All right, on that note, Pamela, thank you so much. Now, before we go, do you have some names to say?

Dr. Gay:                      I do indeed. We are, as always, here thanks to your support through Patreon. You keep us going and allow us to help Susie keep her kids in college. One is there now and is facing finals. Amanda, we wish you the best of luck. You’re gonna rock it; you always do. And you are making university possible for Susie’s kid.

So, I want to thank Jay, Alex Anderson, Dustin A. Ralph, Father Prax, Jason Graham, Ron Thorsin, Claudia Masterlani, Holly Mayor, William Jones, Brent Clenop, Jack, Brandon Wolverton, WordOrigins.org, Jeremy Kirwin, Chad Caliepe, Joshua Pearson, William Loward, Joe Wilkerson, Arthur Lats Hall, Mark Steven Raznock, Bryan Kilby, Tyrone Fong, Iggy Hammock, Omar Del Rivero, Marget Robinson, Neuter Dude, and William Andrews.

Fraser:                         Awesome. Thanks, everybody. I’ll see you next week.

Dr. Gay:                      Thank you. Buh-bye.

Ad Announcer:           Thank you for listening to Astronomy Cast, a nonprofit 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 info@AstronomyCast.com. Tweet us at @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. Our interim music was provided by David Joseph Wesley. The outro music is by Travis Searle and the show was edited by Susie Murph.

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Duration: 34 minutes

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