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I'm constantly amazed at these historical records still exist. Kepler's et al are one thing, but some of the much older from China are also impressive that the information exists today and is still somehow accessible. Now that everything is digital, will they still be available in the future to the same extent that these older analog records have been
You might enjoy the oldest active financial bond, a parchment manuscript from the Dutch water authority 1624.

It still pays a small amount of interest (a bit over 13 Euros per year) provided that the bearer (currently the New York Stock Exchange) if they show up every few years to collect it.

It helped that the written language was modeled on an earlier variation and stayed relatively stable over millennia. I was amazed yesterday that I could understand a bit of a poem written about thousand years ago, and that the poem references a poet that lived another thousand years ago at the time of writing.
I think that yes, they will. Generally these historical records exist because some people went through the effort of preserving them for all these years. I feel this effort is a lot lower when your records are digital and infinitely duplicatable.
Keeping a digital archive is much more expensive than an analog one. In 1990s, if you saved something to floppy, is it still accessible now? Oh, so a new format comes along, so you spend more money to migrate data from old and busted to new hotness format of today. Every time a new comes out? Every other new flavor? What about bit rot so when you try to migrate you've lost readability? Who is paying for all of these format migrations? The ancient Chinese scroll that a monk wrote noting a super novae from the first century is still operational.
Hard drives are non-magnetic & remain readable with good microscope indefinitively. They ALSO allow one to use superior error correction algorithms at ease (analog EC being possible). There exists no obligation to "always mitigate." Actually, from your comment it follows that one should not mitigate constantly.

For large archives, volume determines the cost, because the archive needs to be maintained at constant temprature, humidity etc. Digital storage, being much more dense, costs less.

Architecturally, this will also mean that the further distance between points A and B in the digital archive will grow, I would claim roughly exponentially, slower than what happens in the analog archive. This will affect the costs in myriad ways, which I at the time of writing don't recall.

I think you mean CDs/DVDs are non magnetic and can be read with a microscope.
And even with CD's there are issues.

Writable CD/DVDs have a written shelf life of about 25 years before the layers start to deteriorate and the best ones have a max lifespan guarantee of 100 years. They do rot, just slowly. With a microscope you can of course stretch that a bit but they won't last forever.

Perhaps I was wrong, thanks.
The CDs/DVDs use a metallic mirror. With the exception of certain expensive CDs made for archival purposes, e.g. by Kodak, which used a gold mirror, the reflective layer can oxidize in time, becoming transparent, when it no longer reflects the light.

The pressed CD-ROMs/DVD-ROMs still have pits in the polycarbonate disc, even when the mirror is no longer reflective. Those could still be read with a more sophisticated microscope, e.g. by using phase contrast.

The recordable CD-Rs/DVD-Rs used an organic dye for storing the bits and after a long enough time that dye can be completely degraded and it can become impossile to read.

The rewritable CD-RWs/DVD-RWs store the bits in a layer that can be either amorphous or crystalline, with different reflectivities. After a long enough time, that layer can recrystallize, erasing the bits.

Of all the optical discs that have been available commercially, those with the longest archival time were the pressed CD-ROM with gold mirrors, where the only degradation mechanism is the depolymerization of the polycarbonate, which could make them fragile, but when kept at reasonable temperatures and humidities that should require many centuries.

There have been experiments with write-once optical memories where the bits are stored in an inorganic glass that should easily last for many millennia, but until now I have not heard of commercial products. In any case, none exist at an affordable price.

Might add a new footer:

Please consider printing this email out for posterity.

I literally did this with the email we (college students) got sent by the University (of Alabama: Roll Damn Tide) on the morning of 9/11, which was basically, “We see no reason to cancel classes today.” I thought people would never believe me, because what.
But are digital records really more resilient to catastrophic societal and global changes? Physical records don’t need anything to exist and be read and only time and simple resources to duplicate compared with digital.
> Physical records don’t need anything to exist and be read

Surely you’re joking. Physical records are notoriously fragile. They default to having a single copy and require intentional effort to create and distribute duplicates. They are frequently lost to fires, fading, physical decay, and even just being misplaced for generations.

Digital records have their own issues, but implying with a straight face that the default state of physical records is persistence is a bridge too far.

We have analog records from thousands of years ago, and we still have the technology to use them. I have digital formats from ~25 years ago that can no longer be read. I think the longevity speaks for itself.

Water and fire are equally destructive to digital or analog. Library of Congress has chosen analog vinyl for long term storage over any digital format. I think you're putting way too much faith in digital and totally discounting analog.

The majority of the very old records that still exist are those that have been carved in stone or bronze, or pressed in burned ceramic.

Besides these, there have been huge amounts of written records that have used more perishable materials, like plant leaves, plant bark, wood, papyrus, wax etc.

Almost all of those have been lost.

In the past, carving stone or bronze was hard work, so it was avoided, except for the most important records. Also today, there are technologies to make digital records that could survive for many millennia, but due to their high cost they are used even less than stone carving was used in the ancient world.

Sure, things carved into or painted onto stone have good longevity. That’s an insignificant minority compared to all the paper records that have been rendered unreadable over the same number of years.

Not to mention that accessing those records—finding them in the first place and searching through them—at any kind of scale is essentially completely prohibitive for most use-cases, many of them might as well not even exist until someone takes the effort to digitize them.

Can they actually no longer be read? Or would it just require a few hundred dollars spent on eBay?
At this point, who knows??? None of the data is worth the few hundred dollars nor my time worth messing with it to be honest. I have a couple of Syquest disks that I keep around not so much for the data, but they're just kind of nostalgically cool to me.
> We have analog records from thousands of years ago, and we still have the technology to use them. I have digital formats from ~25 years ago that can no longer be read.

I have physical records from 2 years ago that can no longer be read.

I explicitly called out that digital records having questionable archival properties doesn’t magically make physical records durable by default.
It would make a lot of sense to develop some kind of digital storage medium that’s reasonably easy/cheap to read and write and is designed to endure centuries and hopefully millennia. Of course, this would need to come alongside a reader device which is similarly durable to ensure effectiveness (archives that can’t be read might as well not exist), which I suspect is the greater challenge.
Pressed CDs are supposed to last a while. And I think there are archival versions of CD-Rs.

Or just go for something like microfiche (or even ordinary-scale engravings) with OCR-friendly fonts.

except anything you can build today will be slow and tiny capacity tomorrow. the fact that anyone could suggest a universal format can be developed that will endure all of time where everyone continues to use it for ever after it is introduced is farcical like a fairy tale where unicorns exist.
Survivorship bias. I have no doubt there will be some subset of digital data that survives thousands of years. Probably Rick Astley honestly.
>We have analog records from thousands of years ago, and we still have the technology to use them. I have digital formats from ~25 years ago that can no longer be read. I think the longevity speaks for itself.

We do have records from thousands of years ago, and the fact that we can read them is really cool! But, your argument that therefore analog is 'more reliable' is sketchy. It's true that we have many digital formats that can no longer be read today. But there a few things of note.

One, this isn't a fair comparison. We have analog records from thousands of years ago, yes, but we also have tons of missing ones. (Beowulf once had only one copy, and that was nearly destroyed in a fire in the 1700s. If someone hadn't been quick to rescue it, we could have no idea of Beowulf.) The vast majority is probably missing. A fairer comparison would be to invent a time machine and fast forward a few hundred years. If any file format from today is still readable, then that can be considered a success. Of course, absent a time machine, there's no real way to test this, but judging analog records only be survivors is flawed. (An incomplete list of books which we are aware of but don't have is at https://en.wikipedia.org/wiki/Lost_literary_work)

Two, water and fire might be equally destructive. But if, in theory, all of the print copies of the books in this collection [https://babel.hathitrust.org/cgi/mb?a=listis;c=158633464] get destroyed before digitization, then, so far as we can tell, they're gone. Forever. There's no way of recovering them. But if you can't access the file at HathiTrust anymore, for whatever reason (which might be more likely), there's a copy at the University of Illinois [https://digital.library.illinois.edu/items/bf8640e0-061b-013...] and at HathiTrust [https://catalog.hathitrust.org/Record/100008794]. And since HathiTrust has a mirror, in reality it would require three failing simultaneously.

Maybe a digital file is more likely to be unreadable or fail in some other way, but there are also many more copies. For a Project Gutenberg work to be inaccessible, all of the sites on this list [https://www.gutenberg.org/MIRRORS.ALL] must fail (in reality, it's less, as many are hosted by the same group; but it's still two continents, four countries, and eight providers) and possibly/probably others. For a rare book collection that isn't digitized, it takes one fire.

You’re assuming straight line civilisation. That we’ll always be as we are or more advanced technologically speaking. But civilisation isn’t straight line and one day who knows. Physical records will still be accessible even when digital no longer are.
Wow, interesting take. Some counterpoints from history:

- After the wheel was invented, humanity has never stopped building vehicles with wheels.

- Since the printing press was created, humanity has never lost the ability to mass-copy and distribute information.

- Since airplanes were invented, humans have never been unable to achieve flight.

I'd say it's perfectly reasonable to believe that humans as a whole will never lose the ability to read digital information in the future. Heck, I'd say it's the most likely outcome.

Humans learn from each other. Information "likes to spread". All of known history supports the idea that technology generally advances in one direction.

> - Since the printing press was created, humanity has never lost the ability to mass-copy and distribute information.

> - Since airplanes were invented, humans have never been unable to achieve flight.

This is 600 years and, depending on what you count as an airplane, about 150 years of history. On the scale of millennia, they don't say much about what we will always have.

> - Since airplanes were invented, humans have never been unable to achieve flight.

"Humans" don't mean much in that context. How many countries could build a plane? France, US (albeit they start having reliability issues), China, Russia, India, Japan, and a few others. That list [1] gives only two East-Asian countries, one South Asian and one South American countries. Every other on the list is an European country or a derivative.

[1] https://en.m.wikipedia.org/wiki/List_of_countries_by_aircraf...

That’s putting a lot of eggs in one basket on an assumption. I would say let’s keep it in different formats.

Better to be safe than sorry.

I am curious about the methods used by these early astronomers. TFA mentions Chinese astronomers observing sunspots in the third century BCE. How? Did they use a camera obscura, too? It also casually mentions "reconstructions based on tree rings." What? How do tree rings tell us about sunspot activity cycles?
What? How do tree rings tell us about sunspot activity cycles?

IIRC, solar activity affects the level of charged particles hitting the upper atmosphere which in turn, affects the ratios of radioactive elements in the atmosphere. Traces of these variations can be found in the wood of trees that grew at the time. The tree rings provides dates for the growth.

Are there enough trees from 300 BCE that still survive today?

In the ones that do, wouldn't there be enough thermodynamic diffusion within the tree trunk to obfuscate the true isotope levels in each ring?

It also mentions telescope observations, did those go to a camera obscura after going through the telescope (is that possible?) or were people actually just staring at the sun through a telescope? How did they not go blind?
This group of sunspots triggered a large solar storm and a strong aurora. For comparison, the Carrington event was said to have a strength of -800nt to -1400nt (the more negative the number, the stronger the storm).

The storms on May 11th were verified to have reached -800nt, so right at the bottom of the Carrington event estimates.

Interestingly, while there were a few minor easily fixed issues, the world as we know it did not end as some have said it would with a Carrington scale event.