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A 26,000-year astronomical monument hidden in plain sight (2019) (longnow.org)
278 points by mkmk 4 hours ago | hide | past | favorite | 49 comments




Many Hindus celebrated Malay Sankranti a week ago. It was originally meant to coincide with winter solstice but because the Hindu dates are based on the position of the Sun against the background stars (as viewed from the Earth), precession over the last ~1700 years has driven it out of sync with the tropical calendar.

But is the star map there? This article seems to imply that it got demolished in 2022: https://www.oskarjwhansen.org/news/save-the-star-map

If so that is somewhat ironic. A message intended to communicate a date to thousands of years into the future got demolished a mere 86 years after its creation due to a drainage issue and a contract dispute.


It is currently under reconstruction, it sounds like much of it was beyond salvage and has to be remade but it is difficult to find much info on this, bits and pieces strewn about the web. The project was resumed in 2023 and the BOR stated they were still committed to reconstructing the star map. In 2024 they completed the new underlayment and I have yet to find anything from 2025 other than that Monument plaza is still closed to the public.


At a loss for words. :|

That is a crime of humanity. Terrible!

The same website says that as of 2024, it is slowly being reconstructed: https://www.oskarjwhansen.org/news/2024-hoover-dam-star-map-...

I have once created a pendant to my friends’ wedding following a similar idea. A silver disk engraved one one side with the position of the planets and major moons at the moment of the ceremony. Fun thing is that the Galilean moons orbit fast enough that you can even read the intended minute. https://www.instagram.com/reel/DIpFTPOIP60/

If you have a blog post with a few more technical details, it may be a nice submission for HN. (Do you have a few photos of the intermediate steps to share?)

Some ideas/questions: How is it painted? Is it laser cut or by hand? Did you designed it? How did you do the calculations? Does Saturn have rings? Where is the cutoff? (No Neptune/Uranus/Fobos/Deimos/...) Have you tried to give a different size to each planet?

PS: I showed the video to my older daughter that is interested in astronomy and she likes it.


> If you have a blog post with a few more technical details, it may be a nice submission for HN.

Oh. That is very kind of you. I do have many more pictures and details. I will try to collect them together, and will publish it once it is done. But can’t promise that it will happen soon. So i will answer your questions here in the meantime.

> How is it painted?

The shapes are recessed and the recesses are filled with black nail polish. The excess nail polish was then scraped off from the flat upper surfaces leaving it only in the recesses.

It was very fiddly, and i don’t necessarily recommend this method for anyone. I have since learned how to enamel by melting glass powders onto the metal surface which is both easier and gives a better result. That is how i would do it today. (On my instagram the last reel i posted is showing that process, even though with a different design.)

> Is it laser cut or by hand?

A third and a fourth option. The planet side is machined on a cnc. First I etched the orbits with a v-bit, then cut the planets with a 0.8mm flat endmill, then cut the hole, and finally cut the outline. After that i etched the initials side chemically. As a resist i used self-adhesive vinyl which i cut with a plotter.

To be honest. I wouldn’t recommend this process either. It was super finicky, slow, and error prone. Today i would just etch and cut the metal with a fiber laser. In fact i bought a fiber laser because i got sick of the chemical etching and mechanical machining during this project. :)

> Did you designed it? How did you do the calculations?

I did design it! I’m very proud of it. The initials side was designed in inkscape while the planet side was generated with a python script. The script used the super handy skyfield python library for the calculations. (Which in turn uses the planetary ephemeris files published by the Jet Propulsion Laboratory.)

> Does Saturn have rings?

No ring of Saturn unfortunately. But it would be a cool idea!

> Where is the cutoff? (No Neptune/Uranus/Fobos/Deimos/...)

Unfortunately I don’t have a real good principled answer to this. Because of the machining I had a hard limit on the smallest details I could put on the metal. I did know that i wanted to put the Gallilean moons on there because their short periods meant that they provide good basis for the minutes and hours part of the date. I did know that i also wanted one of the gas giants to provide a “slow hand” to the clock to show the years, and to hopefully stretch out the period before the next time the solar system is in a similar position to very far into the future. And i wanted the inner planets and the Moon so people and future alien minds will recognise it as the solar system. Everything else was just futzing around with the script and finding a good compromise between not making it too large to wear and not making it too crowded either.

> Have you tried to give a different size to each planet?

I did, but it looked uneven and too haphazard to my eyes. Not saying it is impossible to make it neat with different planet sizes but I liked the diagram simplicity of keeping all the planets one size and the moons an other smaller size.

> I showed the video to my older daughter that is interested in astronomy and she likes it.

Oh thank you! That is lovely!


That's so cool! Is there a calculator somewhere that can convert to/from dates and solar system position charts?

Positions at a given time could be simulated in e.g. Celestia (and then projected). The other direction, I don't know.

More:

> Due to the precession of the equinoxes (as well as the stars' proper motions), the role of North Star has passed from one star to another in the remote past, and will pass in the remote future. In 3000 BC, the faint star Thuban in the constellation Draco was the North Star, aligning within 0.1° distance from the celestial pole, the closest of any of the visible pole stars.[8][9] However, at magnitude 3.67 (fourth magnitude) it is only one-fifth as bright as Polaris, and today it is invisible in light-polluted urban skies.

> During the 1st millennium BC, Beta Ursae Minoris (Kochab) was the bright star closest to the celestial pole, but it was never close enough to be taken as marking the pole, and the Greek navigator Pytheas in ca. 320 BC described the celestial pole as devoid of stars.[6][10] In the Roman era, the celestial pole was about equally distant between Polaris and Kochab.

* https://en.wikipedia.org/wiki/Pole_star

* https://en.wikipedia.org/wiki/Celestial_pole


> Marking in the terrazzo floor of Monument Plaza showing the location of Vega, which will be our North Star in roughly 12,000 years. (Photo by Alexander Rose)

I wonder if some content creator 12K years from now will transport to Earth and stream the North Star from this position for likes/views. If that's even a thing then...


I somehow doubt there is any future version of me that regrets joining The Long Now Foundation, and work like this is the main reason why.

If you're in SF you should pay them a visit and buy a coffee at The Interval; I think you'll find it worth the trip.


This is the kind of stuff I love about ancient architecture. It seems they were full of such clever things (or maybe only the few constructions which survived until today).

Its nice to see that some people still care about creating such thoughtful art for modern constructions. It seems that most building of our time are just optimized for fast and efficient construction.

I hope there are many more out there, so that Earth's Graham Hancock of the year 16000 has something to explore on his/her ayahuasca trip.


When you had no electricity to produce light pollution, when you have no TV, printing press, or any other thing to distract your attention, you had plenty of time to look at the night sky. When that also means you didn't have a way to have a shared calendar, you paid more attention to the sky to know when the seasons were changing. When the changing of seasons were key into surviving, you gave it a lot of importance. It's hard to put that into perspective when we can just look at an app to see the specific time/date of astronomical events well into the future.

Having something built IRL would at least inspire a few to actually be interested in astronomy or star gazing.

The buildings then were also optimized for fast and efficient construction.

Those buildings are, of course, gone now.


The precession circle is 144 arc degrees sin 23.5. In an 80 year lifespan precession would move the rotation pole about .44 arc degrees or the diameter of the full moon. Any long lived astronomical observatory in ancient times would have noticed this.

> There is an angle for doubt, for sorrow, for hate, for joy, for contemplation, and for devotion.

I’m so intrigued - what was going on inside Hansen's brain?


Makes sense when talking about human postures and emotions.

Victory/elation/worship corresponds to extending the arms above the head or in a "V" shape, sorrow/grief corresponds to dropping to the knees and holding the head in the hands, etc. These associations seem to persist despite language barriers and great spans of time.


You solved the riddle good sir!

Walking along the millennia, viewing the night's glorious celestial panorama, the registrations on the floor, you'll have successfully circumnavigated the long now, as well the total integral of your own life.


For a hypothesis concerning the precession of the equinoxes and religious pantheons, see https://news.ycombinator.com/item?id=38761574

The concept of "religion" didn't exist until the 17th century or so. Let's not use it here.

You are confusing the thing with the category of the thing.

Religion the category is only a few hundred years old. The things that fall under that category go back at least as far as Neanderthal times.


The conceptualization of religion as a category, is actually quite a bit older. The idea that it was created recently was, well, created recently.[1]

Casadio details it going back thousands of years across cultures.[2]

[1] https://plato.stanford.edu/entries/concept-religion/index.ht...

[2] https://api.pageplace.de/preview/DT0400.9780191045882_A29773...


it's an interesting point, and i don't think it can be resolved quite so neatly. to the people building such monuments, or writing such texts, the activity may have been closer to what we now refer to as "history" or "natural philosophy" (or even "civic infrastructure").

the fact that _now_, we have independent traditions referred to by those terms, and so categorize the ancient practices under "religion" is quite confusing, and it may be productive to make the distinction clear.

for a modern example, suppose we build a skyscraper in such a way that it lines up with, or reflects the setting sun on the solstice. we would regard this as "architecture", not "religion". i would be quite offended if, some thousand years from now, the aesthetic decision is dismissed as primitive superstition.


> i would be quite offended if, some thousand years from now, the aesthetic decision is dismissed as primitive superstition.

Why? I can't imagine being offended if people today, ignorant of the true motivations, dismissed it as primitive superstition, let alone a thousand years from now when I'm long dead.


cf. "The Map is not the Territory"

What?

Wikipedia says similar [1]:

> The concept of "religion" was formed in the 16th and 17th centuries. Sacred texts like the Bible, the Quran, and others did not have a word or even a concept of religion in the original languages and neither did the people or the cultures in which these sacred texts were written

That said, GrowingSideways is mistaken. He is confusing the thing with the category of the thing.

[1] https://en.wikipedia.org/wiki/History_of_religion


> or even a concept of religion in the original languages

IMO this and the sources it cites are wrong. A huge chunk of the Old Testament is about how God had to keep sending prophets to tell the Israelites to stop worshipping other deities. So while they may not have had a single word that was equivalent to 'religion,' they clearly possessed the same concept. They would just use the phrase "worshipping other gods."


I first heard about this in a Graham Hancock book. Found it a fascinating example of an attempt to encode a date that far distant future generations might understand (provided it survives).

That was an excellent rabbit hole to go down while eating lunch :)

Haha, I clicked without reading the URL. Then I read the "01931" in the text, immediately looked at the URL and of course it was longnow.org. Brought a smile to my face.

Thanks for this, at one point I tried to google this monument and didn't find much.

> Having this one fixed point in the sky is the foundation of all celestial navigation.

Only in the northern hemisphere.


I loved this. I wish I had the ability to do the same innocuous deep dive into a easter egg in code - but I fear it would never be discovered at this rate of which AI is generating similar stuff. But much like this article maybe there's a time and place.

> construction of the dam began in 01931

Person in far future:

Was that in the original 01931 as in 1931? Or is that the usual truncation of 101931, since most relevant dates are in this decamillennium?

Leading zeros don't do what you think they do; you need look no further than how people say 03 when they mean 2003. A leading zero does not unambiguously say "there are no implied nonzero digits to the left of this zero".

Just, stop.

Or find some other convention, like, say, =1931. The = means, this is an exact value and not some value truncated modulo a power of ten.


It is a convention of The Long Now Foundation to get people to think of time in terms of 10k years instead of a lifetime at best. It goes hand in hand with their 10k year clock.

https://en.wikipedia.org/wiki/Clock_of_the_Long_Now


I think they are speaking to, not ignorant of, this.

> 10k year clock

a.k.a. cuckoo clock


Why do you imagine that =1931 wouldn’t be equally confusing in some future decamillenium? Arabic numerals have only been around for (charitably) 0.12 decamillenia. Sorry, =.12 decamillenia.

I just look at it and think someone can't even count to 010 in octal.

error: invalid digit '9' in octal constant

In the extremely interesting book about water, cadillac desert, there is a great discussion with a scholar of some kind, I think an archeologist, about the large western US dams and the future. The gist is that the reservoirs will eventually silt up and disappear, but the dams will remain for thousands of years. The silted lakes will preserve clear evidence of their construction in the geologic record of these regions.

We will quite plausibly be known as the dam builder civilization, as these artifacts could very easily outlast the memory of what we call ourselves. It is fitting to embellish them in this way.


During DEF CON XX, I got bored/overwhelmed (it was not my first year attending) — so I decided to rent a car and visit Hoover Dam (this was before the bypass bridge was completed). I drove through the desert 100mph+, in my own little HST jaunt, searching for nothing but concrete's high water mark.

The statues in OP's article are absolutely beautiful examples of Art Deco / 1930s Americana (my local post office was built then, too, and has eaglettes of similar [but smaller] design). I had no idea they were out there until stumbling upon them, and they definitely leave a lasting impression of our forefather's imposing presence. America, fuck yeah!

Wish I had then-known about this "clock," which is definitely hidden in plain sight. Wish we had similarly-lavish federal budgets, today. But worth visiting, both article, statues & dam.


Sounds like it's about the precession of the equinoxes and the new "Age of Aquarius".



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