Questions about the Voyager Records
May 21, 2010 7:18 AM   Subscribe

How did they put images on the Voyager golden records?

I know how you store music on a record. But I read they stored images on the voyager golden records. How? How would you "play" that? Was the music component played like a regular phonograph? Isn't gold too soft to be a good medium for a record? Is gold intrinsically valuable--something to do with its molecular structure, etc?--or do we just think it is valuable enough to be our first contact with space?
posted by jefficator to Technology (5 answers total) 1 user marked this as a favorite
You are I'm sure about to receive a bunch of more specific answers, but there's a lot of useful info on the Wikipedia page, especially the "External links" section at the end.
posted by Mwongozi at 7:34 AM on May 21, 2010

One of those external links is to the CED Magic website which has an explanation of the image encoding.
posted by mkb at 7:38 AM on May 21, 2010

The images are encoded as a series of 512 vertical scan lines per image, and these lines are recorded sequentially on the record. Each scan line is stored on the record as an analog waveform that represents the image brightness along the scan line, from top to bottom. So every position along that vertical line where the image is bright will have a little bump in the waveform there, and this would appear on the record itself as an actual bump in the groove. If you were to play this back thinking it was audio, it would sound like a horrible noise most likely.

The record's cover includes some pictorial instructions intended to help others figure out how the images are encoded, and how to play them back as images. It also shows a sample of the first image recorded (a circle) as a kind of "yes, you've got it right" check.

The records are not solid gold, they're gold-plated copper. This combination of materials was selected for its very good resistance to various kinds of degradation, so that the record would remain playable for as long as possible. It just so happens that a layer of gold plating is an excellent material for this purpose, its value in our society wasn't a factor.

The music component was indeed stored just like a regular phonograph and would therefore be quite simple to hear. The cover also includes instructions explaining how to do this.
posted by FishBike at 7:48 AM on May 21, 2010

(and after writing all that, I see I could have just liked to this page on the JPL site which explains the same thing and includes photos)
posted by FishBike at 7:51 AM on May 21, 2010

Gold is intrinsically valuable at some deep level of our psyche because it's beautiful and eternal. It doesn't rust or otherwise decay. Jewelry made from pure gold stays bright and buttery even when it's been buried for thousands of years. It's also the easiest metal to hammer and bend into shapes without getting brittle. It has a low melting point and since t doesn't oxidize when you heat it, it's not troublesome to cast into molds. Beyond that, wikipedia covers all the different industrial uses.
posted by bonobothegreat at 7:53 AM on May 21, 2010

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