"As part of our species’ search for intelligent life in the universe, the United States flung a Pioneer space probe containing a graphic message far out beyond our solar system in 1972. The scientists associated with it hoped that it would be intercepted by some galactic beachcomber after it left our corner of the cosmos. Newscasters speculated upon how it would find its way to some distant planetary system to be turned over in prehensile limbs we cannot imagine.
Of course, Marconi had already done the same. Seventy-seven years earlier, a small percentage of the magic light from his first radio broadcast did not get reflected back to Earth but passed on through the ionosphere and escaped into outer space. Unlike sound, light is capable of spanning the void. It takes eleven days for sound to cover the distance light travels in a second. From 1895 onward then, the incoming light from distant stars has had to pass through our outward-bound radio wave transmissions.
Imagine the excitement that will be generated when some lone radio ham, on a distant planet orbiting a different sun from ours, one night just happens to turn on and tune in to Earth. What a surprise will unfold, because it is all there - the entire history of the twentieth century as well as music since the Renaissance. Our new radio audience will be able to listen to all our electromagnetic radio transmissions falling on their planet as light from their sun falls on ours. They will hear our extraordinary talents and momentous events as they arrive encoded in these waves. Out somewhere beyond Alpha Centauri, there exists in an ectoplasmic state the messages of Amos and Andy, Adolf Hitler, and Bishop Fulton Sheen, and the music of Ludwig van Beethoven and Bing Crosby. Beginning in the Renaissance, music was recorded through notation. Because of it, the constraints of time were overcome. Now as a result, we can listen to the ensuing centuries’ music. Radio has superseded the constraints of space as well because by converting music to light, Bach and Mozart will resound in outer space forever.
Anyone receiving our early broadcasts would be tuned to musical trends and historical events that have already happened here on Earth. Because of the time it takes light to traverse space, they will not know the outcome; having to wait in nail-biting suspense, like children at a Saturday matinee, to find out who ultimately wins World War II or the answer to the crucial question of whether we will ultimately destroy ourselves in an environmental apocalypse.
With the advent of television we have dramatically increased the outpouring of light-as-information. Now our stellar audience can see what we look like as well as how we sound. The soap opera called the Twentieth Century has expanded out from Earth in a bubble of ghostly light. If, as some astronomers have speculated, there are many different planets out there capable of containing intelligent life, more and more planets will tune in as our programs fan out across space, and soon music and our story will be heard and seen at different times in different places from one end of the universe to the other. "
Excerpt from 'Art & Physics: Parallel Visions in Space, Time and Light'