I recently played my way through the Mass Effect game series, and one of the ideas I found most intriguing was the emphasis placed on "time capsules" sent from one cycle to the next: not only did several Prothean messages last until the in-game present, but presumably each cycle had done the same in an unbroken line, at least going back as far as the development of the Crucible.

Assuming modern-day technology (not Mass Effect-era), would it be possible for humans to leave a message that would confidently be received 50,000 years in the future? Do we have any storage mediums that would last that long, or preservation techniques that could work on that scale? Obviously there are ways that a message could last that long (such as a rock carving inside a dry, untouched cave), but things happen. Caves fill with water, earthquakes crack them open, etc.

But if we had a message that must survive 50,000 years into the future and still be understandable, what would be our best bet for delivering it?

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    $\begingroup$ Hasn't this problem been considered in real life in the context of marking nuclear waste disposal sites? Not exactly the same but certainly similar. $\endgroup$ – mu is too short Nov 1 '14 at 4:48
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    $\begingroup$ Take a look at projects by The Long Now foundation: longnow.org $\endgroup$ – Neil Slater Nov 1 '14 at 11:03
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    $\begingroup$ You could always carve it into the moon. $\endgroup$ – superluminary Nov 1 '14 at 20:44
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    $\begingroup$ Funny that accepted answer solves easy part - leaving the message but does not even attempt to solve hard part communicating what we wanted to say. Pyramids is such persistent message. What does it say? $\endgroup$ – Peter M. - stands for Monica Nov 3 '14 at 19:06
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    $\begingroup$ Our scientists have only some idea of what the glyphs on the pyramids say, and that's only four thousand years ago. $\endgroup$ – Mooing Duck Nov 4 '14 at 0:34

23 Answers 23


My first thought is redundancy. You shouldn't send just one copy of the message, you should send thousands and through different methods. Some thoughts on possible methods:

  • Rock carving in a protective sheath (e.g. amber or a similar substance).
  • Shoot rockets to the Moon and Mars (vacuum doesn't decay things the way that atmospheres do).
  • Build satellites in orbit.
  • Bury on the sea floor and in swamps (hey, it works for dinosaur bones).
  • Hang them in houses for anthropologists to find later.
  • Scatter them around the active volcanoes in Hawaii (think about Pompeii-style preservation).
  • Impress upon your children that the message needs to be preserved verbatim and have them make copies. Deliberately start a tradition of each generation making verbatim copies.

Again, let me say that the most important part is redundancy. Any single message is vulnerable to destruction for any method of transmission. Make as many copies as you can. That way you have a better chance that at least one will survive.

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    $\begingroup$ Ahh, redundancy. Nice, I hadn't thought of that. $\endgroup$ – HDE 226868 Nov 1 '14 at 0:47
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    $\begingroup$ While there are considerable space waste that survive in orbits, planetary surfaces are no better than Earth's when it comes to preserving things. Thighs might not decay due to bacterial/fungal activity, but will suffer from all kinds of physical damages like temperature, collision, radiation and in some cases corrosion. Even moon isn't safe; the flag we left there is now white! $\endgroup$ – Renae Lider Nov 2 '14 at 12:33
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    $\begingroup$ sattelites will suffer orbital decay unless you put them in high earth orbit $\endgroup$ – ratchet freak Nov 3 '14 at 8:54
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    $\begingroup$ Mars is not under vacuum and has an atmosphere (including wind). $\endgroup$ – s0rce Nov 3 '14 at 20:27
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    $\begingroup$ The medium is not a problem. Ceramic plates, printed and fired, will last that long. Redundancy will deal with breakages and missing bits. Making the message understandable 50000 years hence is the real problem. $\endgroup$ – nigel222 Feb 22 '16 at 12:12

There's a very specific existing case study of nearly this exact question.

In the 1970s, the US Department of Energy began investigating what is now known as the Waste Isolation Pilot Plant as a means of safely storing radioactive waste for the next 10,000 years.

Considerable thought was put into the topic of signage: how to indicate to future generations, for whom the very concept or science of radioactive waste may be lost, that the materials buried in this location remain harmful in a very literal sense.

There are some interesting papers from researchers at Sandia on the topic. You can read some excerpts as well.

Do we mark it at all?

I know this wasn't specifically what you asked, but it calls into question the very premise of the exercise. Recorded history goes back only about 6,000 years. The earliest known permanent human settlements go back less than 9,000. So communicating to humans 10,000 years (or, as you posed, 50,000) in the future may simply be impossible.

One alternative (in the case of the WIPP) is simply to bury the material in as inaccessible a place as possible, and assume that any civilization able to discover and uncover it will also be able to detect the danger posed.

The Sandia panel rejected this on legal and (I would say) moral grounds.

How do you ensure the message is physically durable?

This seems to be most related to the core of your question, and the answer is fairly mundane. The final proposal calls for the use "granite monuments, 25 feet high" carrying etched messages, an information center and two storage rooms with similar granite markings, and, buried throughout the complex, the same messages etched on "nine-inch-diameter discs… made of granite, aluminum oxide, and fired clay."

In addition, the same information will be placed in various archives around the world.

How do you ensure the message is intelligible?

The plan calls for the message to be translated into the six official languages of the UN (English, Spanish, Russian, French, Chinese, Arabic) as well as Navajo, the ancestral language of the region.

But come on, how do you really ensure the message is intelligible? How do you ensure that future generations don't destroy the markers? How do you ensure that people take this seriously, anyway?

This is, to my mind, the true crux of the matter. The obvious (and somewhat pulp) analogy is to curses on Egyptian tombs – an Egyptologist might properly translate the text, but he is unlikely to take seriously a warning threatening bodily harm due to vague invisible forces.

Worse yet, the presence of the tomb encourages desecration for motives both historically minded (archeological investigation) and crassly economic (as with reuse of building materials from Roman or Egyptian edifices for more modern constructions).

The WIPP panel was quite aware of such risks, and made a number of suggestions which I will simply quote verbatim:

Each component of the marking system should be made of material(s) with little intrinsic value. The destructive (or recycling) nature of people will pose a serious threat to the marking system.

We decided against simple "Keep Out" messages with scary faces. Museums and private collections abound with such guardian figures removed from burial sites. These earlier warning messages did not work because the intruder knew that the burial goods were valuable. We did decide to include faces portraying horror and sickness (see Sections 3.3 and 4.5.1). Such faces would relate to the potential intruder wishing to protect himself or herself, rather than to protect a valued resource from thievery.

While the below messages differ from the final design, I found a certain sense of Lovecraftian poetry in their directness:

This place is a message… and part of a system of messages… pay attention to it!

Sending this message was important to us. We considered ourselves to be a powerful culture.

This place is not a place of honor… no highly esteemed deed is commemorated here… nothing valued is here.

What is here is dangerous and repulsive to us. This message is a warning about danger.

The danger is in a particular location… it increases toward a center… the center of danger is here… of a particular size and shape, and below us.

The danger is still present, in your time, as it was in ours.

The danger is to the body, and it can kill.

The form of the danger is an emanation of energy.

The danger is unleashed only if you substantially disturb this place physically.

This place is best shunned and left uninhabited.

As a final aside, the suggestions made by a poll conducted by the Zeitschrift für Semiotik and Bechtel's "Human Interference Task Force" are quite interesting in their more far-ranging conceptions – suggestions include the creation of artificial satellites that can circle the earth for millennia, genetic coding of messages into cats, and the creation of an "atomic priesthood" to keep the knowledge sacrosanct.

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    $\begingroup$ The WIPP plan also specifically addresses the problem of language change: part of the planned text is something along the lines of "If this message is hard to read because of damage or because it is written in an archaic language, please re-inscribe it in a physically durable way in a language that your community understands." Hopefully, a "chain" of copied and rewritten messages like this would form a sort of dynamic Rosetta stone, making it far more likely that future humans would get the point. $\endgroup$ – dodgethesteamroller Nov 2 '14 at 21:05
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    $\begingroup$ Anecdotally, when told that one of the premises of the committee when creating the WIPP plan was that no present-day human civilization would survive in a recognizable form for 10,000 years, the Navajo representative said, "Maybe you won't, but we will." $\endgroup$ – dodgethesteamroller Nov 2 '14 at 21:09
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    $\begingroup$ This is an important answer, since it points to people who've already considered exactly this question. The key search term to find out more about this is "nuclear semiotics"; Wikipedia's page on the Human Interference Task Force is a good place to start looking. $\endgroup$ – David Richerby Nov 2 '14 at 22:54
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    $\begingroup$ @dodgethesteamroller I always found that part of the plan to be quite moving. You aren't just trying to control the behavior of future generations, but to make them part of the chain ensuring that the message won't be lost. $\endgroup$ – octern Nov 3 '14 at 16:50
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    $\begingroup$ I'm reminded of the rakshasa vault scene in Zelazny's Lord of Light: "Go away. This is not a place to be. If you try to enter here, you will fail and also be cursed. If you somehow succeed, do not come whining to us when your soul is eaten by demons and your body used to destroy everything you ever loved. We warned you. Signed, The Gods." $\endgroup$ – Paul Z Nov 4 '14 at 17:48

I think we can all agree that whoever finds this message in 50,000 years isn't going to speak English. Or Mandarin. Or Hindi, French, Spanish, Swahili, or, in fact, any language spoken today. So we'll have to figure out a way to communicate with them in a language that we'll both understand.

I'd look to communication with aliens for inspiration. There have been various proposals involving math. For example, we could perhaps use prime numbers in an attempt to show patterns. Any sufficiently advanced civilization could understand that. Or perhaps we would use a modified version of binary code. Maybe we could just decide to create a new language, that would be easy to decode.

To preserve this message, we need to put it somewhere that will protect it for a long time, but will still be open-able in 50,000 years. Paper is, of course, a good choice, but it can degrade in certain environments. Etching the message in metal is another option. Sure, you could store it digitally, but all digital devices have a limited lifetime - certainly less than 50,000 years.

We could encase it in some hard material, such as metal or stone. I know that some smart-alec is going to say amber, so I'll add that here. Essentially, you need something that will survive 50,000 years untouched by the things around it - i.e. a material that's tougher than its environment. Perhaps you could put the message on a sheet of metal and encase it in pure diamond. That way, whoever discovers it could maybe read it through the diamond. Alternatively, put it in a solid glass box and encase the box in some tough, transparent material.

All the ideas above can be summarized like this: Write the message in an easily-decipherable code on a stable medium, stick it in something that will last a long time, find a safe place to put it, and wait 50,000 years. There is another option, though: send the thing to space.

The KEO satellite will (if the project ever gets anywhere) stay in Earth orbit for 52,000 years. It will then re-enter the Earth's atmosphere and, hopefully, carry a message to whoever is still on Earth at that time. (The LAGEOS satellites will also enter the atmosphere - albeit it 8.4 million years from now; their primary function is also not that of a time capsule) You could do something a la KEO and put a message in orbit, where it won't be impacted by severe weather, continental drift, or those pesky humans.

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    $\begingroup$ Great answer - pretty close to this platinum encased in sapphire solution. $\endgroup$ – DeveloperInDevelopment Nov 1 '14 at 0:51
  • $\begingroup$ Holy cow. That's incredible. $\endgroup$ – HDE 226868 Nov 1 '14 at 0:52
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    $\begingroup$ wait... you came up with your suggestion entirely off the top of your head? I'd upvote again if I could. $\endgroup$ – DeveloperInDevelopment Nov 1 '14 at 0:54
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    $\begingroup$ We can be pretty sure they won't speak English, or Swahili, or whatever, but we can be almost certain that the language they speak will be descended from a current language. Write the message in as many languages as possible, and there's a very good chance that a future historian will be able to work out a chain of languages that will let them translate at least one of the copies. $\endgroup$ – Mark Nov 1 '14 at 1:13
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    $\begingroup$ @imsotiredicantsleep, that's why you use many languages: so that if one chain is broken, you still have others. The Rosetta Stone, for example, had Egyptian in both the hieroglyphic and demotic scripts, plus Ancient Greek. $\endgroup$ – Mark Nov 1 '14 at 1:38

I am going to derive on the things already said and add few comments:

1) The message must be interesting to pass on Take a story about Atlantis. Somewhere I heard that it actually describes a story which happened 1000 years before Plato. In other words, story old about 3500 years is still around (and people are still having arguments what and where Atlantis might be)

2) Make it into religion: This point will help you a lot to make your message to pass on in generations. Not only people will be willing and wanting to make copies of your message, but also, your message will be translated to many languages (especially if your religion becomes popular).

And also, you can make sure that your language will be still around even when no one actually speaks it.

3) Build whole society on the message Ok, we know about religious practices old about 7000 years, and still are somehow able to understand the language. But how did we learn about it in the first place? Well, they built the pyramids. They built the Stonehenge. They kept their awesome badass burial places behind.

So, to wrap up:

  • Make your message into religion
  • make the religion very popular and mighty
  • Make sure, the culture and society lives on the religion.

But one thing is for sure: Using those practices above will be able to pass the idea of the message, not message itself. Religions update as society updates, and wonders of the modern world get forgotten in the desert, or the fields, leaving no one behind to tell the stories.

Also, war happens so even following all the rules might get you to dead end.

So, if you need the exact message to be around in 50 000 years, use means as stated in other answers

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    $\begingroup$ That's maybe why the religions were created, that would explain a lot about them. $\endgroup$ – exebook Nov 2 '14 at 10:18
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    $\begingroup$ I VERY much like the idea of "want to send a message 50kyr in the future? Build an entire civilization to do it!" Quite robust, though sometimes results in pesky wars due to disagreements in the faith. $\endgroup$ – Cort Ammon Nov 3 '14 at 2:02
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    $\begingroup$ Makes you want to join religion, right? :) Because dude, someone 2000 years ago wanted to pass message on. We have to carry on 48000 more years! $\endgroup$ – Pavel Janicek Nov 3 '14 at 8:26
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    $\begingroup$ Stonehenge was a strong religious message. Religion is rather unsuitable medium, because it is subject of later reinterpretations. Say biblical flood: was it some tsunami? flooding of Black sea (en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis) Something else? We lost context, and only 7000 years passed. $\endgroup$ – Peter M. - stands for Monica Nov 3 '14 at 19:11
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    $\begingroup$ Religion and culture are prone to mutation though. Every religion has so many schools of thought and sects after just 1000 years. In 50k years the message would have evolved into something else entirely. $\endgroup$ – Muz Jun 30 '15 at 7:58

I just wanted list a few projects that exist and pertain to this question.

LAGEOS - A series of scientific research satellites which use lasers to measure the planet's shape. LAGEOS-1 is predicted to reenter the atmosphere in 8.4 million years and contains a plaque designed for review by future humanity. It was launched in May of 1974.

Memory of Mankind project - Has an estimated lifespan of 100,000 years. They are storing information on inscribed stone tablets and storing them in a salt mine in Austria.

Rosetta Project - It's goal is to preserve around 13,000 pages of information in each of 1,500 languages on a disk made of nickel. The disk can be read with a microscope and is contained within a 4 inch spherical container. One of these disks is on the Rosetta spacecraft that was launched in March of 2004; although it's mission ends in 2015.

KEO space time capsule - Has experienced several delays and has not been launched yet. Estimated to launch in 2015. It's purpose is to reenter the Earth's atmosphere in 50,000 years. It will apparently carry around 24 billion pages of messages on a DVD with symbolic instructions for how to build a reader. It will also contain a drop of human blood and samples of air, sea water and earth encased in diamond.

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    $\begingroup$ "24 billion pages of messages on a DVD"... So unreadable by a typical PC that you could buy 5 years later then? $\endgroup$ – DrMcCleod Jun 13 '20 at 7:46

Encode it with some added redundancy (mutation-resistancy) and inject it in to the DNA of the several geographically distributed organisms (from single to multi cell) with the option of on some species which message manifest itself (whole or in part) some visible way (think zebra stripes as barcode or leopard with QR code).

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    $\begingroup$ I really love this idea, but it also makes you think: Will someone in 50 000 years know, that "this is the message"? And how to read it? Just take 5 minute thinking if today zebras are carrying the message and if we know it that their skin color is the message. And even though - how to read it? ;) $\endgroup$ – Pavel Janicek Nov 3 '14 at 15:46
  • $\begingroup$ Wasn't this a story line in Star Trek: Enterprise? $\endgroup$ – Kevin Krumwiede Nov 4 '14 at 6:43
  • $\begingroup$ Math is universal language and any massage distinguishes itself from "noise" with it's statistical properties (even you can't read it yet, you can still detect its presence). That's what SETI Project do. Or taking a class from Finding Hidden Messages in DNA from coursera do the trick. $\endgroup$ – underscore May 3 '15 at 22:45

There are many long orbit comets that pass by every 50,000 years, and the half-life of Uranium is over 4 billion years, so a powerful multi frequency transmitter encased in synthetic diamond powered by uranium stuck on a 50,000 long orbit comet could be a good long-shot, with another few stuck here in our solar system and on earth.


Even the pyramids are not guaranteed to survive that long.

You could engrave something on the really hard crystal and make sure the words and the crystal are big enough to keep the shape under conditions. The degradation of the shape could be calculated by a chemist. Then put it in to a mountain cave, you need to talk to a geologist here and find the area with the caves that are really old, there are plenty, some mountains are more or less stable for millions of years.

But then again, how you let the receiver know where to look for your message. And do you care who exactly is going to find and read it? And why should they care? They would care if they knew this some how helps them in their lives. So it must be about them. Like we are really curious where our civilization came from, that's why we keep looking for old messages. So basically to make them interested in your message, you need to some how change their lives. And leave a track to a message.

But assuming you can change their lives, which means to have some influence on the society, it is easier to leave the message in the society to pass on in the form of useful idea. That's maybe why religions were created and continents conquered, the greats of the past wanted to leave us the message.

Since we do not know how to create mental entities that would survive in the society for so long, maybe you can choose to modify human genome, and then the scientists of the future will decode your message.

But in fact, I believe that once you left your message here on Stack Exchange, it will most certainly survive for 50000 years. Because this site was created to accumulate knowledge, and is one of the first more or less successful implementations in this area, this site and the dump of all it's database is almost certainly guaranteed to be backed up and copied into all future implementations of knowledge gathering. Once they create quantum computers or even pure-energy computers or any other advances in information processing and storage will be made - most important data will be copied over from old systems. Like those floppy discs, billions of floppy discs are dead, but most of even slightly valuable data from floppies is now stored on hard discs or SSDs, in the cloud or you PC/tablet/phone. And surely future data storage devices will allow super cheap copies of whole Stack Exchange network.

So leave your message here in the comments and add a hashtag #tobereadin52014. So the "Bing" of the future will be able to find it and let the whole mankind "retweet" instantly around the galaxy or whatever. And don't worry about the language, translation tools of the 52014 will easily decrypt your ancient scriptures online. You can even add some formatting and hyperlinks. But probably only few hyperlinks will still work in a distant future. At least those that link to another stack exchange page are surely safe.

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    $\begingroup$ "most of even slightly valuable data from floppies is now stored on hard discs or SSDs, in the cloud or you PC/tablet/phone." that's absolutely, patently false. chrisfenton.com/cray-1-digital-archeology comes to mind but there are countless examples. Also, the Library of Alexandria comes to mind as as knowledge gathering place. $\endgroup$ – chx Nov 2 '14 at 22:18
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    $\begingroup$ @chx, you still can download CRAY OS 1 archive.org/details/Cos1.17DiskImageForCray-1x-mp $\endgroup$ – exebook Nov 3 '14 at 0:28
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    $\begingroup$ @chx digital information largely solves the Library of Alexandria problem... unless you consider the entire planet a single library. Let's hope Moonbase Google gets off the ground soon. $\endgroup$ – octern Nov 3 '14 at 16:52
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    $\begingroup$ The edit was too minor since it was only a few characters so I couldn't suggest it without making other pointless changes to your answer to game the system which would have likely resulted in a rejected edit $\endgroup$ – RobV Nov 5 '14 at 9:02
  • $\begingroup$ @exebook how do you “report in private” on this site? $\endgroup$ – JDługosz Jan 21 '17 at 22:05

According the news from phys.org

Eternal 5D data storage could record the history of humankind.

The storage allows unprecedented properties including:

  • 360 TB/disc datacapacity,
  • thermal stability up to 1,000°C and virtually unlimited lifetime at room temperature.
  • 13.8 billion years at 190°C
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    $\begingroup$ And no drivers available for an obsolete model. $\endgroup$ – JDługosz Mar 2 '16 at 15:04

As has been said, language won't survive. Thus, don't use language in the first place, use pictures. I would a bunch of pictures made out of a pair of metals that won't corrode--not plating but images that go all the way through the metal. Once you have enough pictures to explain you can use a more compact coding scheme.

You can never predict what's going to happen to any given time capsule so you make a lot of them. Put them in varied environments, including on the moon. I wouldn't put things in orbit because anything put high enough up to last 50,000 years is going to be awfully hard to detect. Make it big enough to be spotted and you're asking for it to get smashed.


Place a large terrestrial object in orbit around the earth, a second moon if you will. Place it on a strange orbit so that it clearly isn't the result of nature. Possibly make it a strange shape or color to strengthen the message.

The message is that great beings came before you. Aspire to great things.


Actually, an attempt has been made in the past, and we can still access the message nowadays : bible, kûran,... The best way to make a message go through centuries is to make people alienated about the fact they should spread it.

Edit : This solution has the advantage of removing the message's language problem.

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    $\begingroup$ But the message is not the same as the original. The message changed over time. The question is more about a specific message that does not need to be interpreted. $\endgroup$ – Vincent Nov 3 '14 at 17:01
  • $\begingroup$ How does it remove the language problem? $\endgroup$ – HDE 226868 Nov 20 '14 at 21:39
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    $\begingroup$ Because people will spread the message, and if language evolves, people will make the message's language evolve. We can't speak hebrew but we are still aware of the bible's message, right ? :) $\endgroup$ – johnkork Nov 24 '14 at 11:02

Now we can send a sattelite to a high and stable orbit, that can fly here for 50k years. If orbit is quite high, satellite will not be stopped by Earth atmoshpere, and it can orbit Earth forever. We can add solar panels and radio signals emitting beacon to satellite, so it can be found


Pass it on to your children and make sure they understand the importance of passing it on to their own offspring - and try to be as convincing as you might. If future generations consider your message to be important enough, they will keep passing it on, and it will eventually enter "common sense/universal knowledge". If not, the message will eventually get lost (and probably for good reason). Your question implies that (you believe) any one of us (today) would have knowledge or advice to provide that will still be of relevance in 50,000 years from now. That may be so, but then they had already made it known to us. It were rather pointless to keep from us a message that "must" survive 50,000 years, but preserve it for future generations who might never be born. Any technical approach is rather useless, because it relies on the idea that what technology we know and use today will remain accessible for thousands of years. It doesn't matter which technical solution you opt for today, what really matters are the technical options future people will have to solve the riddles of their day. Physical devices, be they fancy gadgets or carved stones or books, may help your message survive physically (at least for a considerable while), but that doesn't mean your message's meaning will survival too. If anything, the religious scriptures we know today prove this flaw dramatically. What valuable message ever you may have for future generations, it won't make much sense without the proper historical context.


Well its a great Question, I think the best way to preserve a message for 50,000 years and also be understandable to the people is to make draft of useful information e.g rock carving,books,hard disks etc in large cylinders. Make many copies of it and bury some of them in sea, under the earth, below the polar ice, project them in space as a sattalite, send them on moon. someone in future will sure find it.


Just pass it through generation as you would any other scientific information. Wiki mentions that the problem is:

Unfortunately, there is no method available to continuously provide the necessary knowledge about the location of nuclear waste over thousands of years. The culture of earlier centuries becomes incomprehensible when it is not translated into new languages every few generations. National institutions do not exist longer than a few hundred years. Even religions are not older than a few millennia and do not typically hand down scientific knowledge. https://en.wikipedia.org/wiki/Human_Interference_Task_Force

But this is complete bullshit because people who call this "a problem" seem to focus on what they percieve as "important" - i.e. religion, which is inherently subjective and open for interpretation, and thus easily "mutated" with each generation, while scientific knowledge stating objective facts survived longer lenghts of time undamaged. Statements of Pythagorean theorem or Archimedes' principle, for example, is about 2500 years old. There's NO problem.

  • $\begingroup$ Even in a paltry 2500 years, the Dark Ages happened. In 50000 years, it is not at all unthinkable that humankind would experience periods of severe backsliding, assuming it survived for that long of course. And while we did rediscover a lot of classical knowledge after the dark age ended, it would kind of suck if your super important message to the future was only rediscovered a couple centuries after it was important for people to know about it. $\endgroup$ – trevorKirkby Jun 4 '18 at 4:52
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    $\begingroup$ @someone-or-other So, did we lose the math knowledge I mentioned in the Dark Ages? No? What's the problem then? $\endgroup$ – Oleg V. Volkov Sep 27 '18 at 16:18

I would like to develop on the redundancy idea. I think the message should be not only redundant, but it's should be a sort of a physical RAID - a cross-referenced repeatable array of data.

As for the storage medium, I do but think digital storage will cut it for 50 000 years. Contemporary digital storage is actually quite unreliable and decays quickly. Without constant attention and efforts to transfer it to new media the message will be lost quickly. Some answers propose disks and plates from exotic materials - I do not think that is going to cut it too. The storage medium should not be valuable by itself, nothing that future humans would like to melt, turn to jewelry or tools, etc. Rather it should be something comparatively worthless of itself, but durable and chemically stable. Fired clay tablets seem too be a very good variant, carvings on the cavern walls sound good too.

So, returning to the topic of redundancy, I will speak on the example of the tablets. Each tablet is a separate page of your message, and should be explicitly marked as such. So that if a tablet in one storage facility is damaged, it should be easy to understand, which one should be substituted instead. Also, perhaps quite obviously, the tablets with the same parts of the message should be absolutely identical - the same number of rows, the same line separation, absolutely the same shape of letters and drawings (if there are any).

Obviously, each storage facility should also have maps pointing to all the other facilities.

As for the language problem - the Rosetta Stone approach seems the only one to go. Most likely, the tablet should have text in several languages running in parallel. I do not think whether there is any optimal way to select the languages - there is absolutely no way to predict the evolution of languages for time period that big. I would choose languages with drastically different writing systems, just to avoid confusion between languages.

If possible, if the message itself is comparatively short, but decent amount of space can be devoted to storage, the message can include a sort of ABC - tablets with a single drawing and corresponding words in all the language for the most basic and important concepts.

  • $\begingroup$ What do you think about storing Wikipedia in all languages next to the message? $\endgroup$ – Anderas Aug 3 '20 at 16:13

Carve it into extremely hard rock, encase that in Lucite, and put it on the surface of the moon. Unless hit by a meteor, it should last millions of years. Look at Nazca...they scratch some line in the soil, and they're still stumping modern man after? ...an unknown number of years. The reliefs carved in Egyptian obelisks are still sharp, after ??? an unknown number of years, so any deep etching in granite or andesite would last. Or carve it into porcelain...that's supposed to last many eons...or encase it in our most durable plastic, and place it in orbit. If something doesn't have erosion to deal with (water or air/dust storms), images will last indefinitely. Look at the stones from Puma Punko, Teohaunico, or Sacsayhaunan...unknown age, still sharp and precise, and subjected to erosion...?

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    $\begingroup$ I think you are mistaken with all the "unknown"s. We're fairly good at dating things, including relatively constrained estimates for the Nazca lines, ancient Egypt, and the last group of locations (to some degree). $\endgroup$ – Zxyrra Jan 21 '17 at 7:23

This expands on https://worldbuilding.stackexchange.com/a/3433/2700 "Redundancy", but I felt it too large to be a suggested edit.

Not thousands of copies: millions, or even billions.

You know why we can still find dinosaur bones? Yes, bones are kinda durable, some chemical properties etc. But the fact of the matter is, there were many dinosaurs, and the ones we find, are the tinyiest fraction of a faction that happened by chance to endup somewhere that preserves them well.

For super long-term storage you are targetting are the archeologists. They are the people with the interest and expertise to recover and translate the messages.

  • Print it in a book
    • send it to every library, archive and museum etc in the world
    • This is where future archeologists are going to start looking for information.
    • Some will (sooner or later) destroy it; but some small fraction will maintain it as they preserve other things in their collection.
  • Print it on microfilm, and burn it to CD, and any other compact media
    • run a publicity campaign asking people to try and store it, e.g. in household time capsules.
    • Send it to everyone who asks
  • get it digital, and try to get a copy onto every device
    • A virus would be effective in the short term, but would likely turn public sentiment against you.
    • Something like having a free copy of it included in every ebook reader (ebook app) would be good.
    • Having it be used as the secure erase overwriting data common OS system/security suite would result in it being on millions of thrown out government and corporate computers
  • Do everything else in this thread, not once, not a dozen times or a a hundred times but as many times as possible.

Sure all these things have a a very finite life span, but they are really easy to do. All you are trying to do is get lucky. You are buying 1 million lotto tickets.


Ancient hominids managed to leave messages for longer periods of time.

Evidently from this we can gather that the best way to leave a message, is leaving it more than once and more than in one place in different forms.

We know about their religions, their social structures, we know about their families, their conflicts, those are all message they left and the rest we know from archeologists.

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    $\begingroup$ There's plenty of general evidence of people from 50,000 years ago, but I can't think of any specific messages that they left behind that we were able to receive and understand as intended. Can you give examples of what you mean? $\endgroup$ – Nerrolken Jun 12 '20 at 20:16
  • $\begingroup$ @Nerrolken edited. $\endgroup$ – user76409 Jun 12 '20 at 23:29

Leaving aside the problem of actually deciphering the message in 50,000 years, there is one storage medium that is almost guaranteed to make it.

Say it with diamonds.

Most natural diamonds have ages between 1 billion and 3.5 billion years.

Diamond is possibly the most chemically and physically stable material we know. Most natural diamonds were created before humans existed, and will likely be around long after we're gone.

Sub-surface laser engraving allows the creation of internal engraving in a diamond. This is hard, but there are companies that do it today.

Artificial diamonds are cheap. (Really cheap). Thus:

  1. Get yourself a truckload of artificial diamonds
  2. Engrave the message below the surface with sub-surface laser engraving.
  3. Sprinkle liberally

The message is very likely to survive in extremely inhospitable conditions. The only issue is high-temperature fire, which will cause diamonds to burn. this should be covered with redundancy and choosing good locations for your diamond messages.

Diamond's desirability to humans, especially when cut and polished, is likely to remain for a very long time. Human fascination with gems has existed as long as we have been able to produce them, I think it's fair to say that it will continue long into our future. Making the message intrinsically desirable, precious and worth preserving will help it navigate the next 50000 years of human history. Leaving large piles of cut and polished gems in out of the way places around the world will likely ensure that some caches remain in 50,000 years.

You can always use Quartz instead, as is being done right now but really, where is your sense of poetry?

Build a stellar clock

I'd also recommend placing the message in multiple satellites with different decaying orbits. Ensure that every 25 years or so, a new satellite makes it to the surface, with a copy of the message, on the aforementioned diamonds, and instructions to await a second message. That would require a ~2000 satellite constellation, which is a reasonable number.

Having a regular event, that occurs within human lifetimes, and leads to the message being (re)discovered, would also ensure that the problem of language is solved, as it is likely that the new message would be translated every arrival. This narrative of a message from the sky being delivered every 25 years would also likely survive extremes of cultural changes. Such cosmological events as comets or asteroids have been remarked on since we were able to remark on them at all. It's a bonus point that the satellites will likely be visible to the eye and telescope, especially if deliberately coated in reflective material, which means that their orbits can be tracked and their decay predicted, even if we have to re-invent orbital mechanics to do it.

Increase the delivery rate and redundancy to improve the likelihood the message will persist. It's quite conceivable that you could have a yearly programmed orbit decay for 50,000 satellites. (compare this number to the total number of satellites we've sent up so far which is ~8900).

The stellar clock mechanism has the advantage of being very resilient to cultural changes, while at the same time creating an intrinsic cultural focus for any civilisation. Think Halley's comet, except it happens more often and something falls to earth in a pillar of flame. I doubt many civilisations would miss the hint that something is going on.

Risks are that gravitational disturbances would cause the clock to go off sync, although it's unlikely to change the mechanism entirely, it just means that the periods may be perturbed.

Bonus if you call your constellation "Lucy" For one massive, 50,000 years Beatles song joke.

Reality check: This assumes that the Lyapunov time of earth-orbiting is greater than 50000 years, which may not be the case at all, although it strongly depends on the orbit specifics, in which case it's a pretty idea but not really viable.

Build a foundation

Isaac Asimov's Foundation Series is predicated on this exact problem, and how Harry Seldon solves it. I'll let Asimov explain this more eloquently than I could in his books :)

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    $\begingroup$ Except Seldon's Plan was a failure. In the end, Trevize made an intuitive leap, negating all that calculation. At least 3 new kinds of humans showed up. The Mule. Gaia. The Solarian kid, invalidating the base assumptions Seldon made. Sorry, 4 new kinds of human, including Trevize, who had the quality of making incalculable intuitive leaps. In fact, Seldon's plan was the tool used to bring the Galaxy into lockstep. Let me repeat this: In the end the course of the Galaxy was determined by some dude guessing! One dude! $\endgroup$ – chiggsy Dec 15 '20 at 19:20

2 methods come to mind;

  1. Quartz memory discs. They are a are currently existing technology that will store information for close to 12 billion years! - The problem? Designing a reader or instructions for building a reader that will last as long.

  2. Carve/mark giant symbols on the moons surface pointing to a secure storage facility there containing information engraved on metal tablets or some other system that can survive being buried in a underground chamber in a vacuum for the period required. - The problem? Getting there to recover the info.


There is a technique that might be interesting and not "far future" (currently we can only show a proof of concept, we have not tested it, but it's not far of the "self driving cars" future).

The bigger problem with a message that needs to outlive ourselves is that it needs to "stay alive": as in, it needs to not be destroyed.

To stay alive we can quite literary just do that: either make a robot that is self replicating and intelligent enough that it knows how gather supplies to make multiple copies of itself which.

Or even simpler: encode the message as a DNA sequence into the DNA of some species, many virii actually carry "information" about our history this way. And if you can encode it into a strong bacteria like the cyano bacteria it's probably going to last for a 100s of million years.

  • $\begingroup$ How would someone know that the message is there? Imagine a civ breakdown or even just a tech flatline from today and on. How would you discover and decipher the message? $\endgroup$ – Anderas Aug 3 '20 at 16:16

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