Microsoft's project Silica [0] may hopefully provide really long term, large capacity archive grade storage on earth. I wonder what effects interstellar radiation has on them.
Glass is pretty inert, full stop. It would depend on the voxel size but I imagine as long as you have more than a few hundered atoms per voxel/bit you will have survivability on the order of millenia, even in high radiation environments. Someone would have to do the nuclear cross section calculations to get a real bit error rate but glass is very tough stuff.
I wonder if that's actually feasible for this application.
Microdots managed about 32MiB / square centimeter (from the "you could fit the Bible 50 times in a square inch") measure. That's a completely arbitrary density to achieve, since it was photographs which were enlarged and shrunk, and you could hypothetically use any encoding for your gold etchings, and it also leaves out the question of "how fine can you etch gold plates while still having the engraving be 'robust'".
But in any case, that gives you a target area of ~325 square meters for a 100TiB archive.
That's a lot, but not like a crazy obviously impossible number like a million square km or something.
Assuming you can cut the etching down to 1m squares and stack them on top of one another that should be no problem at all. Assuming each layer is 1.2mm thick (same as a CD) that's a volume of 1m x 1m x .390m, it would fit easily in a payload fairing of any rocket that can get it into orbit.
The volume isn't a real problem, but nearly half a cubic meter of gold should also have a mass of ~7500 kilograms. You're also looking at a cost of ~$350 million, US.
(Which isn't necessarily impossible, but still a lot, especially for an interstellar probe.)
7.5 metric tons is well within the weight limit for a Falcon 9, so add about $57m for the launch costs for a total project cost of probably around $500m.
That puts it in the realm of the Voyager probes for total cost.
there is no need to put a data storage archive on something shot out into interstellar space. geostationary telecommunications satellites are at a sufficiently high enough orbit that they will likely outlast human civilization. We could destroy ourselves with nuclear war, regress to a stone age level of technology, rediscover spaceflight and go find them long before the orbits of any of them decay.
okay, high Mars orbit. Quite a lot less delta-v requirement for some theoretical several thousand kilogram chunk of long-lifespan data storage, and easier to discover and retrieve, than achieving solar escape velocity (look at the delta-v budget for the new horizons probe vs. its total size and weight, for instance).
I'd probably put a signaling system on it. Some large RTG using elements with a long half life and extremely redundant systems that send a weak signal towards earth, just over the background noise. Some regular signal ("DATA" as a morse code) that repeats from an unknown object orbiting mars?
I'd bet that any civilization would be flying there ASAP to see what it is about.
The crux is really making a simple radio transmitter that can survive that long but the parameters are very weak (ie, the frequency is allowed to shift so long as it remains somewhat in a region that can be received on earth's surface, it needs a very long last power source but doesn't need a lot of power, unidirectional transmission is fine as long as it arrives).
Storing that amount of information in a way that an unknown alien species would be able to read (even assuming technical expertise greater than our own) is a huge problem.
Keep in mind that they don't know our written or computational language and there's nothing about our technology that is inherently self-explaining/obvious.
Even the assumption that they'd use binary computers (rather than trinary, or other technology not based around electrical voltages) is open to debate.
An idea I've seen is including messages at several levels. At the outermost level you describe in very basic format how to build a magnifying glass. From there you have diagrams that are legible that describes how to build a microscope. From there you have more than enough space to describe the basics of what else is in there and to start describing your language. I'm thinking optical storage in a clear rock of some sort, as has already been prototyped.
If you assume motivated readers and human-level intelligence, you could end up with good results. It might take a decade or three, and a lot of mental firepower, but they could get there.
(The outer layer is the hardest, since our information density is lowest. Our "description of how to build a magnifying glass" might cover just the basic optics of curved glass and a very basic description of how to get to glass and how to curve it correctly, leaving a lot of the details up to the finder. After all, we did it without help. We're not so much trying to solve this problem for the finder as help them on their way.)
So, before jumping in to argue, remember I'm stipulating decades of dedicated effort by presumably an interested consortium of... whatever they are. I think we can safely stipulate an amount of effort at least as large as our society has dedicated to, say, Linear A and B, or the Voynich manuscript. I'm not trying to spec "Ugh wanders out of the jungle, sees our pretty rock, and personally has a 20th century civilization up and running in 10 years" or anything crazy.
>I'm not trying to spec "Ugh wanders out of the jungle, sees our pretty rock, and personally has a 20th century civilization up and running in 10 years" or anything crazy.
Quite coincidental, there is currently an Anime running named "Dr. Stone" which is quite exactly about that; jump starting human civilizatio from the stone age to modern day as fast as possible. Atleast in-story it's been a few months and they're currently building radios and have a waterwheel generator.
Yeah, it's on my list. My strategy is generally to wait until I can just mainline the entire season, so I tend not to watch the latest seasonals, but it's definitely on my list when the season is done.
In Vernor Vinge's "A Fire Upon the Deep", a very advanced civilization in the outer galaxy that can't reach where we are for $REASONS has as a persistent hobby speculation on the fastest way to bootstrap advanced civilizations, assuming essentially-perfect knowledge of physics instead of blundering around.
Not necessarily for aliens ... but why not keep a backup in a safe place outside the dangers of earthlings ?
OTOH, I think a sufficiently advanced alien intelligence will be able to decipher the information structures we use regardless of differences in technology. It's possible though there will be missing links in that archive, which will need to be supplemented with a primary secondary and high school curriculim.
/Godel, Escher, Bach/ has an interesting thought experiment about exactly this.
If one were to receive an object, how would it be indicated that there is a message embedded in there? Given that a intelligence could recognize that there was a message embedded, could it eventually be deciphered?
This is an interesting idea because there's a lot of radical political and philosophical publications on there. Brill's Historical Materialsim book series is on there almost in its entirety.