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.
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:
From my cursory web searches, your photos may be the first online evidence that the restoration project was indeed completed.
This is the second-best way to doxx HN users I've ever seen.
And the best way is...?
Job ads. It's job ads.
Thank you for the confirmation! This is so good to hear.
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.
It's in pieces, evidenced here: https://www.oskarjwhansen.org/news/save-the-star-map-decembe...
At a loss for words. :|
That is a crime of humanity. Terrible!
This is horrible! I always wanted to visit this. :(
The same website says that as of 2024, it is slowly being reconstructed: https://www.oskarjwhansen.org/news/2024-hoover-dam-star-map-...
On Google maps, someone posted a photo from 9 months ago, explaining the restoration.
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.
"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."
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!
> On my instagram the last reel i posted is showing that process, even though with a different design.
Permalink: https://www.instagram.com/cogs_and_curios/reel/DTNtEFPjEGQ/
> And i wanted the inner planets and the Moon so people and future alien minds will recognise it as the solar system.
I think it was successful.
Out of curiosity were the positions (especially of the Galilean moons) actual simultaneous positions, or positions as seen from Earth, given the ~40 light-minutes distance between the Earth and Jupiter?
Very good question! I believe they are simultaneous positions. Skyfield has facilities to calculate the light propagation adjusted position but i didn’t use them. Would you have? Is one more “correct” or more likely to be anticipated by future sentients? I’m always unsure about ther design details.
Also there is an other skewiness. Because obviously the drawing is not to scale the moon position can be correct from the sun’s coordinate frame or the Earth’s coordinate frame, but not from both. I choose to make the moons “correct” in the sun’s coordinate frame. Meaning that if you were hovering over the ecliptic frame looking down at the Jupiter during the wedding and rotating the pendants so the sun is in the direction the real sun is, then you would see the moons under you in the same arangement as they are on the pendant. But if you would stand on the surface of earth (during the wedding) and look at Jupiter you would see the moons in a different arangements than a tiny human standing on the earth dot looking at the jupiter dot. (And not just because of the time delay difference, but because the coordinate systems are different.)
Which is weird. Because the wedding happened on Earth, not hovering over the plane of the eliptic over Jupiter. So maybe that was a weird choice. (And not even talking about how north-centric it is that i decided to draw the diagram from the “north” looking down at the eliptic, instead of from the “south” side. These are all kinda culturally driven arbitrary choices. Would love to have none of those present but I haven’t found a good and principeled way yet.)
Wow such a great answer, thanks for sharing the thoughts that went into this. It's crazy that there are so many considerations when taking into account the limited speed of light.
The speed of light is most frustrating. I find myself alternately wishing it was infinite or slowed down to 'disc world speeds' depending on which of the two would make my current project easier.
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).
That's so cool! Is there a calculator somewhere that can convert to/from dates and solar system position charts?
To calculate the orbital positions i used the skyfield python library. https://rhodesmill.org/skyfield/
They have a very handy example right on the landing page how one can calculate the positions and angles of a planet from a date.
The inverse was a bit trickier. But I also implemented a script which could “solve” a given picture backwards and give us a date. I believe i used binary search to narrow the date down first for the planet with the slowest period, and then refined the date around that timestamp using the position of the planet one faster. That way the estimate got more and more accurate and i didn’t need to brute force search a large time interval. (I applied the assumption that the date to be found is within half a saturn year from our current date, but if that assumption were incorrect it would have resulted in a solver failure during the refinement and thus detected.)
Positions at a given time could be simulated in e.g. Celestia (and then projected). The other direction, I don't know.
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.
A few pharaos remain only known for being so poor architects that their hastily built temples needed renovations after only 2-3 generations.
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_
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.
Also, since y’all seem interested, feel free to AMA.
“It is likely that at least major portions of the Hoover Dam will still be in place hundreds of thousands of years from now.”
From the article itself, the Pyramids are only 12,000 years old. Every other Ancient Wonder has been destroyed.
Essentially there’s a Major Cataclysm about every 10,000 years, and a ‘Minor’ one about every 5000 years (Burkle Crater impact being the most recent).
How do you assume any parts of the Hoover Dam would be intact or even visible “hundreds of thousands of years from now”?
That quote actually comes from Zander Rose’s Long Now Foundation article, not from me or Oskar Hansen.
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.
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.
Discussed at the time (of the article):
A 26,000-Year Astronomical Monument Hidden in Plain Sight - https://news.ycombinator.com/item?id=19124698 - Feb 2019 (57 comments)
For a hypothesis concerning the precession of the equinoxes and religious pantheons, see https://news.ycombinator.com/item?id=38761574
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.
> 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.
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.
"""
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.
That was an excellent rabbit hole to go down while eating lunch :)
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).
Graham Hancock the fraud?
I think author and journalist is how he presents himself. Or pseudo-scientist according to Wikipedia. But yes Graham Hancock.
And to think we're all here building b2b SaaS
Those ad impressions won't optimize themselves!
My wife has bought a few of these for significant dates as gifts:
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.
As a European it took me a few seconds to parse.
Nonsense formatting.
I find it a bit silly. When we refer to 70 CE or 500 CE we don’t add zeros in front.
It's not silly when you consider what longnow stands for. They look at "now" on a 20,000 year scale so the extra zero is just emphasizing that 01931 is still the "long now".
It’s so arbitrary. We have at least a few hundred million years before Earth is entirely uninhabitable. Why not use 000001931, then? Not ambitious enough, I guess.
Our written history already goes back over 6,000 years. We can actually understand what people back then wrote. We don’t need unbroken year numbering, or leading zeros, to understand that. The calendar has been reset and changed multiple times. It seems like a mis-focus on something that doesn’t really matter.
I don't see it as a serious attempt to create a better way to write down the year. To me, it's a whimsical attempt to give the reader a little pause to think about long time periods, which is what this project is all about. That makes me smile and remember that I'm just a small spec of dust, not to be taken too seriously in the grand scheme of things. I like it.
> 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...
> transport to Earth
They’ll almost certainly still be on Earth. Fundamental physics is unlikely to change in the next 12,000 years.
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.
> Having this one fixed point in the sky is the foundation of all celestial navigation.
Only in the northern hemisphere.
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.
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.
Could plate tectonics conceivably throw off the alignment of this monument within the ~10ky timescales involved?
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.
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.
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.
I actually went to get away from some friends, whom were presenting that year (they needed prep time — and I needed escape). Top 10 memories made by myself out at Hoover Dam, watching as the bypass got completed (that is another incredible feat of engineering).
Definitely a cool experience, and I'm glad I did. My last year attending DEF CON me and a Hadoop buddy (nobodies) just walked up onto a stage [during a terrible presentation] and started drinking whiskey with the ESL speaker (again: nobodies) — predicting we'd get banned from attending (but didn't — nobody cared... audience appreciated the break from hard-to-understandings).
The 26,000-year cycle is also known as the Platonic Year.
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 ?
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.
Thanks for this, at one point I tried to google this monument and didn't find much.
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
3.82
plein d’impressement: a series of cordialities
>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.
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.
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.
Sounds like it's about the precession of the equinoxes and the new "Age of Aquarius".
Destruction of art is the only crime I think should receive the death penalty. You’re making the world darker for everyone.