One of my favorite radio shows / podcasts right now is a show called radiolab out of New York’s WNYC. Each episode they have a theme focused on some aspect of science and how it affects our lives; think This American Life but Science and you’re close. One of my favorite episodes talks about the space capsule sent out in the 1960’s as a representation of human civilization.
Among the things on the ship was a record (as in phonograph) made of gold with recordings of music and sounds from all over the world. The scientist being interviewed explained that the record would last millions of years because it was made out of gold and that any beings that had a basic understanding of physics – which any space faring beings would presumeably have – should be able to figure out how to play it.
Now this got me thinking; this is true. A phonograph is essentially a transcription of a sound wave onto a piece of solid material, it is an impression made by an actual phenomenon; and so is film. An alien intelligence should be able to read any analog recording because it is analogous to the physical phenomenon it is trying to record. A digital recording, however, is encoded. And that code is based on human logic; something an alien intelligence may not have experience with.
Let me take a few steps backward for a moment and get into definitions of analog and digital. An analog recording is analogous to the physical phenomenon it represents. A phonograph has a copy of the sound waves recorded upon it etched into its surface. If we could look small enough, we’d be able to see the same peaks and valleys we’d see if we could see sound itself. Likewise a frame of film actually resembles the light at the moment in time when the photograph was taken. With analog recordings there is no encoding and decoding so to speak, anyone with experience of the physical world can understand it.
Digital recordings however are not like this. In a digital record the information is broken down into a code, typically numbers, stored, and then reconstructed later. In a digital picture, a computer records a number with the location and appearance of each pixel. When you look at the picture, the computer reconstructs the image based on this code. This form of recording is great because it lets us make unlimited copies of something and store it in a far smaller space than an analog recording. But the catch is: in order to see the image, we need that code. And if I’m an alien who has no idea how humans think, where will I get that code?
Initially, one may be tempted to assume that, since any spacefaring life form must be of advanced intelligence, it would be able to decipher the code. But this answer falls victim to one fatal assumption: that alien logic is neccessarily the same, or at least even close to human logic.
Logic, as we understand it, is something internal to the human experience; we have no plausible reason to assume that logical structures in the mind of another life form, much less one not of this earth, would resemble ours. It is these very logical structures which form the basis of our understanding of the codes we create, and without them, decoding would seem nearly impossible.
Analog recordings though do not rely on this frame of reference but rather use the laws of physics as their cipher. Assuming the laws of physics hold true throughout the physical universe, an analog recording could be deciphered simply by analyzing its physical properties. The analog recording exists in the world external to the human mind, making it possible for it to outlast human existence.