I'm conceptualizing a sci-fi short story. In it, the main character will find an obelisk type object which has been half-buried for who knows how long. Well, the answer is about 20,000 years. The object needs to contain lots of detailed information, equations in math and physics. What would be a good way of setting up this object such that it is plausible that it has survived this long and is still legible. The character who is finding this object will be about as advanced as the ancient greeks, he will not have any modern technology so encoding it on a hard drive in a supercomputer wouldn't really work as he probably wouldn't be able to operate it.

Is stone-carving the best option? What metal can we make with our technology now that could possibly last that long and be engraved so that the information would remain.

The 'apocalypse' that has supposedly separated these two civilizations will not be in the story, I only need to set up the object and make it manageable and plausible.

Timeline: -Modern humans create object containing what we know about the universe so far, math and physics. -Some unnamed event happens which leaves our civilization in shambles and mankind starts anew (on earth still). -Tens of thousands of years pass as civilization rebuilds and enters into the age of the ancient greeks again. -Our story takes place here where the main character is akin to a student of Pythagoras or Euclid, who finds this object that the ancient (modern) humans had created which shows him all of the things they achieved through mathematics and physics.

Imagine Euclid finding a stone obelisk or epitaph which has written on it Einstein's equations, Feynman Diagrams, the constants of nature etc. and trying to make sense of it all.

-EDIT: I just thought of this method: The humans create the object to be computerized and deploy it into orbit around the earth, with a program counting the time until it needs to descend back down in which case it would be safer in orbit than here on earth with the elements. Would that work better?


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    $\begingroup$ See en.wikipedia.org/wiki/Rosetta_Project and en.wikipedia.org/wiki/HD-Rosetta and note that the engraving size can be varied so that a diagram visible to the naked can show how to build a microscope capable of reading more densely packed microengraving on the disk. Lifespan is estimated at 10kyears but different materials are available that should easily reach well beyond 20kyears. Mass produce these and stash them all over the planet. $\endgroup$ Jun 10 '21 at 2:26
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    $\begingroup$ I've given you a slight tag edit to be more apt by their definitions and our usage, feel free to revert if you feel I've missed your point. We invite you to take our tour and read-up in the help center about how we work (as and when you have time, it's long). Welcome to Worldbuilding. $\endgroup$ Jun 10 '21 at 2:27
  • $\begingroup$ Thank you A Rogue Ant I certainly will take a look at it and thank you for the edits! Thank you aswell GrumpyYoungMan that is very very close to what I was looking for in trying to achieve. I wonder what materials could possibly extend the life that long, either way, it's not entirely crucial as I could bend that time scale a bit and still have it hold together I think. 10k years could be enough time for the humans that remained to at least rebuild something similar to the ancient greeks. -I actually did not know that we were really trying to create something like this, I would love that! $\endgroup$
    – user179809
    Jun 10 '21 at 2:34
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    $\begingroup$ If you need longer term, you can look at the technique used here southampton.ac.uk/news/2016/02/5d-data-storage-update.page?1 with an estimated lifespan of 13.8 billion years even at 190 C. The research touts high density storage but, as the pics show, it works just as well for engravings or microengravings. $\endgroup$ Jun 10 '21 at 3:07
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    $\begingroup$ Welcome to the site! There are several questions that might already answer your question. See the following: worldbuilding.stackexchange.com/questions/125442/…. worldbuilding.stackexchange.com/questions/200553/…. worldbuilding.stackexchange.com/questions/3429/…. There are many more like it. $\endgroup$
    – Trioxidane
    Jun 10 '21 at 5:50

Engrave the Moon

As human civilisation fell, a group of scientists used a solar power satellites power beaming laser or a spacecrafts main battle laser to engrave several regions of the moon.

The engravings could be of different sizes. Perhaps big enough to be deciferable with the unaided eye. In your case making them small enough that one would need a primitive spyglass/telescope to seem them would be sufficient. Why was this hinderence introduced? To ensure that whoever finds the information first is a least somewhat scientifically minded and doesn't turn the data into religious dogma.

You can't really prevent degradation of the carvings (which would be glassy burn marks on the lunar regolith), but you can carve the same things several times onto the surface in different places. The data is saved via redundancy.

The lunar environment is significantly more stable and less aggressive than anything on Earth, so beating the few 10000 years other methods suggested should be trivial.

As a bonus, this method allows you to hint at old lunar bases and landers, which could have preserved data, technology and even biological artifacts in the cold vacuum for a long time.

Additionally you can introduce even smaller carvings which the young civilisation can only find, when their telescopes get better. You could actively incentivse them to get into space by hinting that there is more advanced knowledge on the far side of the moon.

This obelisk will actively guide the development of its civilisation.


Proper preservation already exists, kinda

If something isn't broken, don't fix it. The best existing techniques for preserving data over long periods of time have been provided to us by the ancient Egyptians. First you need to engrave your data on to a material that would best survive the passage of time, stone or ceramic is the best candidate for this. Then you provide an adequate protection from erosion and the elements, which the Egyptians did by building the pyramids around the very things they wanted to preserve.

The only real challenge comes in deciding WHAT kind of data to preserve and which format to preserve it in. The language or, most importantly, the semantics of the data itself, could be lost not only by the slow passage of time, but also by many variables that tend to wipe entire civilizations within a single generation. Conquest, total genocide, wide-scale disasters and similar things have to also be taken into account.

How would one go about providing a time-capsule for the far future without actually knowing if the future generations would actually consider preserving them as well is the biggest question and, once you've answered that, you pretty much solved this problem.


I've been thinking about engraving, but you must be sure of some importants things before doing so:

  • Material : sould be incredibely resistant through time, so maybe some kind of alloy, or self-conservating.
  • Your message : is the language universal ? Are you thinking of Mass Effect probe? How your artifact should interact with the user ?

You could also go for something that open itself to show its content to the user, like an armored closet



You just engrave the data in durable rock. A nice 3-D lasercut works well, providing both durability and good information density.

Make many, *many, many copies, scattered all over the place. The more delicate or detailed ones can be put in orbit, or on the moon. This helps preserve the artifacts, and ensure that only the worthy get access to it. No good engraving the secrets of a quantum hyperdrive where cavemen will get their grubby claws on it!


Engraving and containing

If you want a relatively low tech solution, you should just engrave and then protect with a layer. For example, you engrave something in granite and enclose it in amber. It is clear enough to read, especially after sanding the outside after many years. You can possibly replace the granite and amber with things more durable. As long as one can be visibly engraved and it can be encased by a see-through material that is relatively strong and can take the brunt of erosion, you're golden. Instead of engraving you can do a lot more. You can make an evolutionary path to use the items stored within, like special long term USB sticks (I'm not saying current USB sticks, but a solid state volume that can be read after many years). That way you can eventually release a ton of information of the digital age when they progressed far enough.

Make many to prevent unexpected breakage or loss of the tablets. Spread them mostly in area's that are stable and erosion proof, or at least erosion proof for the materials used.

Why engraving?

Shooting things into space, locking them away in vaults and the like are all nice idea's, but the possible loss of these rise each year. They rely on finding them again and mechanics that might fail, while limiting the amount that can be spread. Engraved and encased tablets can be made in multitude, at relatively low costs and spread around at easily to find locations. They can be added to any other high tech solution, vault or cult worshipers that memorize them to your hearts content later, but the information must be as stable with the least chance of loss as possible from the start.


A form of writing technology that has survived millennia is clay tablets. Clay tokens were used in Mesopotamia around 9000 bce. Pictographs were recorded on clay tablets around 4000 bce and writing was being recorded on clay tablets around 3000 bce.

Large clay tablets offer a solution to what you want. They also offer a way to mass produce many tablets so the information can be stored in numerous locations.

With research and development the right type of clay and the best thickness of tablet can be determined.

The concept behind linotype machines could be adapted so that clay tablets could be imprinted with both text and line pictures. The tablets would then be glazed and baked to harden them and give them a durable surface.

To ensure durability, the tablets would need to stored in a dry thermally stable environment away from all the elements: sunlight, wind and dust abrasion, water erosion and deposition of water soluble minerals. Desert sands are ideal for this. Thermal stability would be needed to prevent deterioration from stresses induced by rises and falls in temperature.


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