I sometimes wonder what people from the past would think of our modern technology. The other day when putting a CD in my computer while reading the thread about the PBS 1900 house I thought, what would the scientists of the day think about a CD if they came across one? If they put one under a microscope could they detect the pits or figure out the binary codes? Could the cryptography experts of the day decode the CD? Could they even understand it’s function or how it was made?
What an interesting question…I suspect witchcraft would be brought back into fashion and you would be drowned, burned, hung, drawn-n-quartered, pressed by stone, and stoned (with rock, not dope). However, none of these would be in order. I hope you understand you heretic! Now stop fooling around with the timeline so my quantum computer will come back.
I not so sure that the craftsmen who made mechanical music machines would have been too overwhelmed by CD’s. It’s just the digital age adaption of a technology pioneered by mechanical means. Some of their work was nothing short of mechanical genius. I recently visited a museum specialising in this area, and I was staggered by the degree of precision engineering that was required to build a couple of the German/Austrian/Swiss machines on display.
What was most interesting was the fact that these machines were “progammed” with the insertion of large metallic discs, that had holes punched through them, rather like the punch cards that early main frame computers used. Each disc held about a dozen tunes, and each “track” was cued up automatically by a slight realignment of the disc and the tracking mechanism. Fascinating to watch, and surely a precursor to the electronic storage mediums we take for granted now.
It would be impossible for them to figure out because they would not have known about quantum mechanics, microchips, or lasers. Binery code would be the easy part. Mathematics has been advanced far beyond that for a long time.
Not a very good mirror is it, it’s distorted and has a hole in it.
They’d be at a bit of a loss. Microscopy just wasn’t good enough to resolve the pits in a CD at the time, so they couldn’t even get started.
However, the 19th century had some damned fine scientists. Although they couldn’t begin to understand the details, if you TOLD them that the disc stored information in the form of tiny pits, they could understand that. Hell. Leonardo Da Vinci could. Likewise, they’d get it if you told them that you had a machine which could read the information to produce a stream of numbers ranging from 1 to 65536, 44000 per second. They’d know you could plot these numbers on a graph vs. time to produce an approximation to a continuous function. And they’d probably understand that if you had another machine which could convert this function into a mechanical displacement, you’d get sound out of it.
Trouble is, they’d never believe you!
I read a related story about this, it was an essay about the gold-plated analog LP disk attached to the Voyager satellites, I think Carl Sagan wrote it. He theorized about what a totally alien culture would think when it found the LP. It was written just like an vinyl audio record, so if the aliens looked at the grooves with a microscope, they would clearly see analog waveforms. The problem would be whether they could figure out how to spin the record. They decided that the hypothetical aliens would notice that the groove was one long continuous spiral, and should be decoded in a linear fashion, even if they couldn’t figure out that it was intended to be spun on its axis. Sagan included a diagram that was supposed to indicate the axis spinning.
But he speculated further on what would have happened if they had included a CD. The CD’s decoding method, unlike the LP, is not obvious from its construction. In order to decode the CD, the aliens would need detailed instructions on algorithms for decoding, it would not even be obvious that it contained audio data at some parts and stored images in others. Due to the obvious difficulties of writing a universal set of instructions for decoding CDs, they went with the analog LP, which they decided was “self-documenting” as to playback method.
The essay described the CD as a final break with our analog environment, a completely irreducible abstraction of our audio environment into digital form. Boy I wish I could find that essay again, it contained a ton of interesting thinking.
any idea what’s on it?
The Voyager CD is called something like “Greetings from Earth.” It contains the spoken greetings in many different languages, as well as encoded photographs of earth. I think they even sold the album on the open market at one time.
Getting back to the OP, the most astonishing thing they’d find about a CD would be plastic. In 1900, clear plastic hadn’t yet been dreamed of. It would blow their minds that something clear like glass could be light like bone or paper and almost as flexible as metal. If you really wanted to astound them, bring back cellophane. The chemists would have a field day, and would doubtless have to reject some old theories. Speed up atomic theory decades.
Derleth: Ever peel an onion? If you’re careful, you can pull off a flexible, transparent, lightweight layer (it’s actually only a single cell thick-- great for HS biology microscope labs). Certainly, cellophane is a lot stronger, but they would probably assume it was something similar.
The images and sounds on Voyager’s two gold records were released years back on a CD-ROM called Murmurs of Earth. You might be able to find a copy if you scrounge deeply.
They’d have no idea what it is. They’d use it as a frisby or something. They wouldn’t be startled or amazed, they would just think “Hey check out this frisby”.
I don’t think a 19th Century scientist would mistake a CD for a pie.
“Frisbie” was only the name of a pie company (founded in 1871) until Wham-O introduced the Frisbee flying disc in 1958.
I assume you mean a pressed CD with no label. Forget about them understanding in any way that it was a data storage device, there are too many degrees of technological separation re storage methodologies between then and now for that to happen. They would more than likely think it was an optical device of some sort given the prismatic characteristics of most pressed CD’s.
Probably not much without a CD player and a handy 120 volt power outlet. 
I had the impression that it didn’t take much technology to reach the fundamental limits of optical microscopes. Was it in the 20th century that we reached this limit?
They’d probably think it was some sort of jewlery or novelty toy, like those glasses that turn everything you see into rainbows.
scr4 said:
“I had the impression that it didn’t take much technology to reach the fundamental limits of optical microscopes. Was it in the 20th century that we reached this limit?”
You’re quite right, and I was wrong. The limits of optical microscopy resolution were reached early in the 20th century at about 200 nm. Compact disc pits are about 500 nm wide and 3000 to 8000 nm long, so they could be resolved with 19th century optics. I doubt they could do anything with the information though.