Just curious. Do any plastics have true archival lasting powers?
Teflon is almost indestructible. If buried, it might last many millennia.
What conditions is the OP interested in? Buried or in a cool, dark basement, Vs. in a house somewhere, Vs. outside in sunlight will make a big difference.
Also, I wouldn’t be surprised if the different recycle numbers have different degradation properties.
There are a number of variables. Most plastics are formulated with stabilizers, antioxidants, free radical acceptors, etc. The more stabilizers, the longer they last. UV, heat, and moisture reduce how long a plastic lasts. Flexible vinyls and other plastics contain low molecular weigh materials to soften them. Their loss makes the plastic shrink and embrittle.
I think CD’s and DVD’s are made out of polycarbonate. Packed away in the dark and climate controlled, I am sure they would last a long time. Maybe the popular SD cards and USB sticks too. Their data is actually on silicone isn’t it?
The plastic cover of a USB stick will last a lot longer than the data kept inside of it. Your guess was correct. The data is trapped electrical charge in an oxide layer on a floating gate transistor, which is close enough to “in silicon” in layman’s terms. The data on a USB stick is pretty fragile, comparatively, and a USB stick can lose its memory much more easily than a CD or a hard drive can. Don’t use USB sticks as backup devices. Even under the best of circumstances, the data on a USB stick is only going to last something like 5 to 10 years. The plastic case will certainly survive a lot longer than that.
CDs and DVDs are plastic with a small layer of metallic particles on them. Data is “written” by punching holes (with a laser) in the metallic layer, and then the hole, or lack thereof, is read by a laser. The metal layer degrades over time, so DVDs and CDs also won’t last anywhere near as long as the plastic parts of them. Your DVD or CD may look ok after ten or fifteen years, but you may not be able to read the data off of it much longer than that.
As for the OP, the typical number thrown around for most common plastics is that they’ll last about 500 years in a landfill. The way this number was derived is kinda hokey, though, and a lot of experts don’t think that plastics will degrade that quickly if they aren’t exposed to sunlight. Other estimates are in the 1,000 to 1,500 year range. Since plastics haven’t been around all that long, the experts really don’t know for sure, all they know is that the plastics degrade very slowly and will be around for a very long time.
For “archival” purposes though you would need to store data on the plastic somehow. Off the top of my head I can’t think of any data that is currently archived on plastic in such a way that it would last for hundreds of years. If you wanted to make some sort of archival time capsule though, imprinting data on plastic probably wouldn’t be too bad of a way to do it. Stone and gold would probably be better materials to use, though.
I have a couple of CDs that are 25 years old. They play just fine.
I have CDs older than that, too. I suspect they last a bit longer than the 10 to 15 year number that the “experts” like to throw around. I don’t have a better number to give though so I just quote that one.
Well, how many things do we make that will last a few thousand years?
Not many, I’d say.
What manufactured/built things do we have around not that are more than even 3,000 years old? I can only think of a few:
[ul][li]the pyramids & Sphinx in Egypt (but partially demolished).[/li][li]some ancient statues (mostly damaged)[/li][li]walls of some ancient cities (though maybe they have been rebuilt over the years?)[/li][li]Dams, harbor piers, canal water gates (but these too, have probably been replaced/rebuilt over the years).[/li][li]Some prehistoric cave paintings (in France, I believe).[/li][/ul] That’s about all I can think of.
The technology in a commercially made CD is different from that in a CD-R or a CD-RW disc.
There are intact glass bottles that are over 2,00 years old. If kept from mechanical damage, glass could last for many 1,000s of years.
The polyethylene milk bottles that I keep some water in are already degrading in my closet and periodically leaking.
I actually asked about this in a thread that is several years old. The replies didn’t really provide a consensus as to what the condition of the CD’s might actually be. I’m thinking that while the music produced from them sounds fine to the human ear, the millions of bits of data may have degraded and are actually less accurate than what was on the disk on the day it was manufactured.
If what I am saying is inaccurate than I am fully willing to be corrected.
Even if the data on a CD has started to decay, CDs contain error correcting code that can cope with and correct a certain level of errors from decayed bits.
Though if they really are decaying, eventually it’ll reach a level beyond what the error correcting code can cope with, and you’ll start to get missing or corrupt audio or data.
lots of pieces of ceramics, including with cuneiform writing from ancient Mesopotamia. That’s how we know about the 3rd dynasty of Ur from 20th century BC. (darn commies…)
I don’t think this is quite correct. The pits and lands in a pre-recorded optical disc aren’t burned by a laser - they’re pressed from a master - the master is manufactured by a photoresist process which uses lasers, but is more like photography than laser engraving.
For consumer-recordable optical media, the recording laser alters (reversibly, in re-recordable varieties) the properties of a thin layer of dye on top of the metal layer.
Some of the dead sea scrolls are over 2100 years old. I’m no expert in antiquities, they are just the first thing that comes to mind. I think that an expert could name any number of things of an age of the same order.
Also the (implied) extrapolation doesn’t work.
Just because not many things from 2k years ago have survived to now, doesn’t mean that few of the things we are creating today won’t last 2k.
For one thing, we’re creating thousands of times more “stuff” than two millennia ago. For another, many of the materials we’re using are synthetic and have been designed to be inert / resistant to degradation.