I’ve been thinking about this subject for some time, but it was only after reading this article (and the ones linked there) that I decided it would make a good post. The article is about a new kind of data storage, created by femtosecond laser bursts into fused quartz. In other words, as the researchers helpfully put it, memory crystals. They say that these bits of glass can last (for all practical purposes) indefinitely.
A common trope in fiction, especially near-future sci-fi, is the mysterious artifact left behind by an ancient, yet unbelievably advanced, civilization. Whether it’s stargates in Egypt, monoliths on Europa, or the Prothean archives on Mars, the idea is always the same: some lost race left their knowledge, their records, or their technology, and we are the ones to rediscover them. I’m even guilty of it; my current writing project is a semi-fantasy novel revolving around the same concept.
It’s easy enough to say that an ancient advanced artifact exists in a story. Making it fit is altogether different, particularly if you’re in the business of harder science fiction. Most people will skim over the details, but there will always be the sticklers who point out that your clever idea is, in fact, physically impossible. But let’s see what we can do about that. Let’s see how much we can give the people a hundred, thousand, or even million years in the future.
Built to last
If your computer is anything like mine, it might last a decade. Two, if you’re lucky. Cell phone? They’re all but made to break every couple of years. Writable CDs and DVDs may be able to stand up to a generation or two of wear, and flash memory is too new to really know. In our modern world of convenience, disposability, and frugality, long-lasting goods aren’t popular. We buy the cheap consumer models, not the high-end or mil-spec stuff. When something can become obsolete the moment you open it, that’s not even all that unwise. Something that has to survive the rigors of the world, though, needs to be built to a higher standard.
For most of our modern technology, it’s just plain too early to tell how long it can really last. An LED might be rated for 11,000 hours, a hard drive for 100,000, but that’s all statistics. Anything can break tomorrow, or outlive its owner. Even in one of the most extreme environments we can reach, life expectancy is impossible to guess. Opportunity landed on Mars in 2004, and it was expected to last 90 days.
But there’s a difference between surviving a very long time and being designed to. To make something that will survive untold years, you have to know what you’re doing. Assuming money and energy are effectively unlimited—a fair assumption for a super-advanced civilization—some amazing things can be achieved, but they won’t be making iPhones.
Material things
Many things that we use as building materials are prone to decay. In a lot of cases, that’s a feature, not a bug, but making long-term time capsules isn’t one of those cases. Here, decay, decomposition, collapse, and chemical alteration are all very bad things. So most plastics are out, as are wood and other biological products—unless, of course, you’re using some sort of cryogenics. Crossing off all organics might be casting too wide a net, but not by much.
We can look to archaeology for a bit of guidance here. Stone stands the test of time in larger structures, especially in the proper climate. The same goes for (some) metal and glass, and we know that clay tablets can survive millennia. Given proper storage, many of these materials easily get you a thousand years or more of use. Conveniently, most of them are good for data, too, whether that’s in the form of cuneiform tablets or nanoscale fused quartz.
Any artifact made to stand the test of time is going to be made out of something that lasts. That goes for all of its parts, not just the core structure. The longer something needs to last, the simpler it must be, because every additional complexity is one more potential point of failure.
Power
Some artifacts might need to be powered, and that presents a seemingly insurmountable problem. Long-term storage of power is very, very hard right now. Batteries won’t cut it; most of them are lucky to last ten years. For centuries or longer, we have to have something better.
There aren’t a lot of options here. Supercapacitors aren’t that much better than batteries in this regard. Most of the other options for energy storage require complex machinery, and “complex” here should be read as “failure-prone”.
One possibility that seems promising is a radioisotope thermoelectric generator (RTG), like NASA uses in space probes. These use the heat of radioactive decay to create electricity and they work as long as there’s radioactivity in the material you’re using. They’re high-tech, but they don’t require too much in the way of peripheral complexity. They can work, but there’s a trade-off: the longer the RTG needs to run, the less power you’ll get out of it. Few isotopes fit into that sweet spot of half-life and decay energy to make them worthwhile.
Well, if we can’t store the energy we need, can we store a way to make it? As blueprints, it’s easy, but then you’re dependent on the level of technology of those who find the artifact. Almost anything else, however, runs into the complexity problem. There are some promising leads in solar panels that might work, but it’s too early to say how long they would last. Your best bet might actually be a hand crank!
Knowledge
One of the big reasons for an artifact to exist is to provide a cache of knowledge for future generations. If that’s all you need, then you don’t have to worry too much about technology. The fused-quartz glass isn’t that bad an option. If nothing else, it might inspire the discoverers to invent a way to read it. What knowledge to include then becomes the important question.
Scale is the key. What’s the difference between the “knowers” and the “finders”? If it’s too great, the artifact may need to include lots and lots of bootstrapping information. Imagine sending a sort of inverse time capsule to, say, a thousand years ago. (For the sake of argument, we’ll assume you also provide a way to read the data.) People in 1016 aren’t going to understand digital electronics, or the internal combustion engine, or even modern English. Not only do you need to put in the knowledge you want them to have, you also have to provide the knowledge to get them to where it would be usable. A few groups are working on ways to do this whole bootstrap process for potential communication with an alien race, and their work might come in handy here.
Deep time
The longer something must survive, the more likely it won’t. There are just too many variables, too many things we can’t control. This is even more true once you get seriously far into the future. That’s the “ancient aliens” option, and it’s one of the hardest to make work.
The Earth is like a living thing. It moves, it shifts, it convulses. The plates of the crust slide around, and the continents are not fixed in place. The climate changes over the millennia, from Ice Age to warm period and back. Seas rise and fall, rivers change course, and mountains erode. The chances of an artifact surviving on the surface of our world for a million years are quite remote.
On other bodies, it’s hit or miss, almost literally. Most asteroids and moons are geologically dead, and thus fairly safe over these unfathomable timescales, but there’s always the minute possibility of a direct impact. A few unearthly places (Mars and Titan come to mind) have enough in the way of weather to present problems like those on Earth, but the majority of solid rock in the solar system is usable in some fashion.
Deep space, you might think, would be the perfect place for an ancient artifact. If it’s big enough, you could even disguise it as an asteroid or moon. However, space is a hostile place. It’s full of radiation and micrometeorites, both of which could affect an artifact. Voyager 2 has its golden record, but how long will it survive? In theory, forever. In practice, it’ll get hit eventually. Maybe not for a million years, but you never know.
Summing up
Ancient artifacts, whether from aliens or a lost race of humans, work well as a plot device in many stories. Most of the time, you don’t have to worry about how they’re made or how they survived for so long. But when you do, it helps to think about what’s needed to make something like an artifact. In modern times, we’re starting to make some things like this. Voyager 2, the Svalbard Global Seed Vault, and other things can act, in a sense, as our legacy. Ten thousand years from now, no matter what happens, they’ll likely still be around. What else will be?