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?