The Interstellar Postcard: Voyager's Golden Record

In the fall of 1977, the unmanned probes Voyager 1 and Voyager 2 were launched from Cape Canaveral. The twin spaceships carried copies of the Voyager Golden Record: a gold-plated copper phonograph record and stylus. These records contain the culmination of our knowledge about ourselves, and our planet. 

Side A

"Play me!" : the binary code along the outside indicates the record should be played at 0.27 rpm

"Our 'hood": This is a pulsar map of our galaxy. Pulsating stars, or pulsars, blast constant beams of radiation while they rotate, sort of like a lighthouse that shoots X-rays. This map shows our exact location in both space AND  time, using binary code that describes the frequency and characteristics of these beams. It's SO much information crammed into a simple, rich design. 

"Our chemistry": This figure shows the lowest energy state of a hydrogen atom, along with some information on quantum spin. The line between the two states indicates the transition time is used as a universal constant. 

"Attention: Use VCR": These diagrams instruct our interstellar recipient on how to view the video portion of the recording. Binary is used to indicate the waveform of the transmission and other information. The circle is the first image seen, if the scan is successful. It also has colour: a red image is followed by a blue one, followed by a green. A spectrum of the sun is also provided, to show how we interpret colours.

Finally, the record case features an ultra-pure sample of Uranium-238, which has a half-life of 4.468 billion years. This provides a chronological scale, against which all of the molecules of the spacecraft could be measured. Otherwise, aliens might find it in a trillion billion zillion years and be like ''when did THIS happen''.

Side B

Pictures: 

the Earth (duh)
DNA
a supermarket
crocodiles
a demonstration of licking, eating and drinking,
Toronto's Pearson airport

Sounds:

"Greetings!" in 55 languages
volcanic eruption
frogs
heartbeats, laughter
a wild dog, a domesticated dog

Bach, Chopin, a Peruvian wedding song, a Pygmy girls' initiation song

(full list)

Now, we wait

I find this incredibly exhilarating, and a little bit scary. We sent out this little package, humbly offering up a distilled glimpse at the essence of our planet. 

We don't know how advanced the receiver is. Maybe there is more advanced sentient life out there, and they've decided to refrain from interfering with us. Maybe they watched as the records were prepared and cast.

Two weeks ago, Voyager 1 reached the edge of the Milky Way and entered interstellar space. It is the furthest thing from Earth, ever. It will eventually fall into an infinite orbit around our galaxy, and whoever it is would have to be smart enough to get into space and grab it, which is no easy feat. 

Our hearts are on our sleeves, wrapped up in a little bundle streaking away from Earth at a THOUSAND KILOMETRES PER SECOND. 

Who's going to pick it up?