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A 26,000-year astronomical monument hidden in plain sight (2019)

565 points| mkmk | 1 month ago |longnow.org

113 comments

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krisoft|1 month ago

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.

andrejk|1 month ago

I'd have to look at what it looked like before, but when I visited there earlier this month, I didn't see any restoration in progress and the star map was open. I didn't take a ton of photos in that area, and here are the only two of the monument I grabbed:

https://photos.app.goo.gl/qgJ3x5za82EiFz5P7

ofalkaed|1 month ago

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.

venusenvy47|1 month ago

On Google maps, someone posted a photo from 9 months ago, explaining the restoration.

throw0101a|1 month ago

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

heresie-dabord|1 month ago

"Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The phenomenon is named after the Serbian geophysicist and astronomer Milutin Milanković. [...] variations in eccentricity, axial tilt, and precession combined to result in cyclical variations in the intra-annual and latitudinal distribution of solar radiation at the Earth's surface, and that this orbital forcing strongly influenced the Earth's climatic patterns.

The Earth's rotation around its axis, and revolution around the Sun, evolve over time due to gravitational interactions with other bodies in the Solar System. The variations are complex, but a few cycles are dominant."

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

krisoft|1 month ago

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/

gus_massa|1 month ago

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.

hydrox24|1 month ago

If others are interested in getting something like this — there's an Australian firm already doing a good job at scale (but slightly different to parent).

https://www.thenightsky.com/

BrandonY|1 month ago

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

breckinloggins|1 month ago

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.

vedmakk|1 month ago

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.

dylan604|1 month ago

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.

sneak|1 month ago

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

Those buildings are, of course, gone now.

giraffe_lady|1 month ago

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.

laszlojamf|1 month ago

Slightly off topic, but it's interesting to see the same phrase "the long now" pop up in different contexts independently and mean very different things:

https://www.epsilontheory.com/the-long-now/

Both are pretty obscure references for now, but I can easily imagine a world where they both become widely known in separate groups. Like the word "legacy" has hilariously different connotations for software engineers as compared to _everyone else_

interleave|1 month ago

Related: Huge fan of Long Now here.

Asking "How would you build a 10k year clock?" is one of my favorite ways to get to know people, say, at parties.

With a few seconds to mull it over, so far EVERYONE has had at least one strong, novel and leftfield idea that I had not heard or thought of before.

My favorites included: A mirror on the moon, bio-engineered crops and the Pyramids of Gizeh.

aaronstreet|1 month ago

I’m the author of the original posts on https://oskarjwhansen.org and can confirm that the Star Map restoration project finished near the end of 2025. I’d been planning to get an announcement post up this week but saw the HN attention and wanted to put fears to rest.

aaronstreet|1 month ago

Also, since y’all seem interested, feel free to AMA.

ummonk|1 month ago

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.

MomsAVoxell|1 month ago

I visited it the first time as a teenager in 1986 part-way through a driving tour from LA to Mexicali and Vegas and Tahoe and so on.

I had a Sony Walkman and one of the 'trip tapes' I'd had packed for my family driving-tour vacation, was Eddy Jobson, Theme of Secrets. So his visceral strings and landscape arrangements were my personal soundtrack all the way to those crazy angel sculptures and beyond, to Death Valley and Vegas and all that jazz, until we got back to San Francisco, where I'd got his tape.

The eternal nature of that spot really seemed feasible to me. Even if the water dried up completely, it'd still be somewhere, some time in the future, some people would meet .. and perhaps wonder just what it was all about, some tens of thousands of years ago.

akshay326|1 month ago

> 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?

Liquix|1 month ago

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.

peter303|1 month ago

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.

DougN7|1 month ago

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

staplung|1 month ago

I think the most likely end fate of the Hoover dam is that humans dismantle it. Eventually, Lake Mead will silt up enough to make the hydro plant useless (it will take centuries to silt up completely but silt will choke the plant long before that). De-silting the reservoir is not a realistic option.

Hopefully, we'll have alternate means of power generation that nullify the dam's economic viability long before then but water supply and flood mitigation are other functions that need consideration. Silt will eventually destroy those functions as well however.

ifh-hn|1 month ago

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).

spartanatreyu|1 month ago

Graham Hancock the fraud?

carlcortright|1 month ago

And to think we're all here building b2b SaaS

fc417fc802|1 month ago

Those ad impressions won't optimize themselves!

staplung|1 month ago

The star map comes up at the end of Joan Didion's essay "At the Dam":

""" I walked across the marble star map that traces a sidereal revolution of the equinox and fixes forever, the Reclamation man had told me, for all time and for all people who can read the stars, the date the dam was dedicated. The star map was, he had said, for when we were all gone and the dam was left. I had not though much of it when he said it, but I thought of it then, with the wind whining and the sun dropping behind a mesa with the finality of a sunset in space. Of course that was the image I had seen always, seen it without quite realizing what I saw, a dynamo finally free of man, splendid at last in its absolute isolation, transmitting power and releasing water to a world where no one is.

"""

avhception|1 month ago

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.

antonvs|1 month ago

I find it a bit silly. When we refer to 70 CE or 500 CE we don’t add zeros in front.

timc3|1 month ago

As a European it took me a few seconds to parse.

Nonsense formatting.

accrual|1 month ago

> 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...

antonvs|1 month ago

> transport to Earth

They’ll almost certainly still be on Earth. Fundamental physics is unlikely to change in the next 12,000 years.

lalos|1 month ago

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

Only in the northern hemisphere.

kevinpet|1 month ago

Not even in the northern hemisphere. Celestial navigation is about shooting altitudes for known bright stars. At least three ideally five. This could include Polaris, but it doesn't need to. Source: watched some old training videos about celestial navigation after reading Fate is the Hunter a while back.

kraig911|1 month ago

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.

tim333|1 month ago

I wonder if you can pin down other cycles in the sky to pinpoint how many years after the big bang? I guess the appearance of galaxies must change.

ProllyInfamous|1 month ago

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.

hakkoru|1 month ago

Heh, a group of friends and I also visited the Hoover Dam while we were in Vegas for DEF CON one year. Was a really cool experience for sure.

ljsprague|1 month ago

>It is likely that at least major portions of the Hoover Dam will still be in place hundreds of thousands of years from now.

Kinda sus of this.

u1hcw9nx|1 month ago

It can be hard to recognize the heaps of dirt on the riverbanks. The internet claims the Hoover Dam could last 10,000 years, but I don't believe that for a second.

Dams are not permanent structures without maintenance. If they are holding back water or if water is flowing through them, they will eventually erode and their foundations will collapse.

Because the main structure lacks rebar , it will last longer than most modern structures, but it won't last nearly as long as 2,000-year-old Roman structures made with volcanic ash and lime because it uses Portland cement.

There is bigger and more immediate problem. Hoover Dam ends with siltation long before concrete erodes. The Colorado River carries massive amounts of sediment. Eventually, the lake behind the dam will fill with mud, turning the dam into a giant waterfall. Once water starts flowing over the top of a arch-gravity dam rather than through controlled pipes, scouring at the base will undermine the foundation.

anentropic|1 month ago

Could plate tectonics conceivably throw off the alignment of this monument within the ~10ky timescales involved?

staplung|1 month ago

Not really. The axis of the earth's rotation is not affected by plate tectonics and the star map is recording where the earth's northern axis is pointing as precession slowly moves it around a circle. The star map could certainly move around or get broken up by plate tectonics over that timescale but it's not really aligned with anything in a meaningful way so that doesn't matter.

The stars themselves will move - relative to us - and eventually some of them will disappear but nothing much is expected on that front for much longer than 10ky timeframes.

flomo|1 month ago

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

hopelite|1 month ago

The civilization that created that must have been a wonderful place and probably was taught how to create such things by aliens.

Is sarcasm, but it may as well not be since that America is long dead and gone and has been replaced by an America that really needs to be renamed at this point.

gku|1 month ago

The 26,000-year cycle is also known as the Platonic Year.

IG_Semmelweiss|1 month ago

is that the time it would require to complete 1 revolution, shown specifically in figure 1 of the article ?

Also - wouldn't the north star(s) (polaris, deneb etc) also move, even if slightly, in that period of time as well ?

zehagray|1 month ago

The fact is; this kind of knowledge are mostly pursued by people called "lunatics" and this is taking science held back in fringe cases. But sometimes lunatics are right too

mockbuild|1 month ago

3.82

plein d’impressement: a series of cordialities

kazinator|1 month ago

[deleted]

krisoft|1 month ago

> Just, stop.

Why do you mind what others do?

> A leading zero does not unambiguously say "there are no implied nonzero digits to the left of this zero".

Nor does it anywhere say that it means that or that it should mean that. To me the the leading zero in front of 1931 means “Do you think a thousand year is long? Think on a longer scale.” It is a vibe.

> Or is that the usual truncation of 101931, since most relevant dates are in this decamillennium?

The sentients of 101931 won’t be confused because they will know that 01931 refers to our time. Simply from all the context clues acrued. Such as the fact that the document was written in HTML (an archaic markup format rarely used past 8470 as any historicaly inclined sentient of that age would know) and found saved on an SD—card in the backpack of an astronaut who crash landed on the far side of the moon in 2457. Same as you don’t get confused about which milenia a roman public inscription unearthed in Pompei refers to.

bravoetch|1 month ago

Their stated aim is to encourage long term thinking. It appears they scored a bullseye with your response.

eddieh|1 month ago

error: invalid digit '9' in octal constant

bregma|1 month ago

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

GavinMcG|1 month ago

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.

Aloisius|1 month ago

> Leading zeros don't do what you think they do

It's has been pretty normal for clocks with digital displays to include leading zeros for seconds, minutes, hours and/or days for about a century. Doing the same for years, while unusual, doesn't seem particularly confusing. And of course, there is precedent with things like ISO86011 - where 0400 is the year 400 CE.

I'm not sure why one would assume it was a truncation of 101931. That doesn't really make much sense. The first decamillennium digit started at 0, just like the first millennium digit started at 0. 101931 would be 99,905 years in the future.

> how people say 03 when they mean 2003

Making people think beyond that form of casual shorthand (even omitting the apostrophe which would indicate the omission!) is sort of the point? Never mind that 03 doesn't necessarily mean 2003.

calibas|1 month ago

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

lisp2240|1 month ago

Destruction of art is the only crime I think should receive the death penalty. You’re making the world darker for everyone.