Are we alone in the universe? Are there other intelligent forms of life in space or are we alone? These questions have been on mankind’s mind, since we consciously reflect our existence and raise our gaze toward the starlit sky.
With the beginning of space travel, there arose the idea, of sending messages to potential extraterrestrial life. The question, which information is suitable, a representative picture of the entire human race and their lives on planet Earth, is particularly exciting.
As part of the Apollo missions 11 to 17, stainless steel lunar plaques were attached on the descent stations of the lunar modules, which bore an image of the Earth and the signatures of the participating astronauts (also partly the then US president Richard Nixon). Besides, each of them reads a text message, for example the Apollo 11:
»Here men from the planet Earth first set foot upon the Moon July 1969, A.D. We came in peace for all mankind.«
The plaques remained on the surface of the Moon, together with the entire descend station.
On board of the interstellar space probes Pioneer 10 and Pioneer 11, gold plated aluminum plaques were attached in 1972, which depicted a variety of graphic representations, among others a man and a woman, and various information about our solar system. By portraying a hydrogen atom, data of size is conveyed in a mathematical principal. One could speculate that a large part of humanity possibly understands the message on the plaque only partially. What if extraterrestrials would have a similar experience?
With the space probes Voyager 1 and Voyager 2 that were launched in 1977, a data disk made of gold with image and sound data were sent into space, and are known under the name of »Voyager Golden Record«. The disks look like vinyl records and contain diverse information, spoken greetings in many languages with photos and music of many cultures.
It remains to be seen, whether we will ever receive an answer, and possibly the messages will only be discovered in millions of years and humankind does not exist anymore. Well, at least it was worth a try …