Gazing into space and wondering what is up there is something humankind has done since the begginings of time. The first stargazers distinguished the movement of planets from the stars; as the telescope appeared a whole new horizon was upon us to explore. We we able to find out that we do not have the only star that has planets revolving around.
There's a lonely feeling when we look up, that compels us to scream out, wanting to find out that we are not alone. we scream, hoping that in the future, another civilization may scream back.
The first radio message aimed towards potential extraterrestrial civilizations was sent by Soviets in 1962, aimed to Venus with the words: "MIR" ("peace" or "world"), "LENIN" and "SSSR", in Morse Code. The political content should not surprise us, considering that at that time the Cold War was an everyday fact. The space race, was just another of the fields of battle.
This message, is still in its way to the star HD131336 in the Libra constellation.
Lets introduce ourselves.
The messages focus changed over time. No random signals were sent anymore, we started designing messages that delivered information about us. In 1974 the first signal of this kind was sent from our planet: The Arecibo Message. Written by Frank Drake & Carl Sagan. In November 16th, 1974: from Arecibo, Puerto Rico, aimed to the Great Globular Cluster in Hercules (M13), in the Hercules Constellation. It'll get there... in 25000 years.
Radio signals were not the only way we attempted to communicate outside of our planet. Pioneer 10 & 11, carry an gold-anodized aluminum plaque, that have inscribed representations of humankind and our advances. It is estimated that both probes are around 100 AU (or 9.300.000.000 miles/15.000.000.000 Km, if you prefer the "pleb" measurements for distances).
The space probes Voyager 1 & 2 were designed to leave our Solar System, and also have information about us with them. Launched in 1977, both have golden discs with graphic information similar to the Pioneers' AND a collection of sounds and images from our planet. Steps, laughs, thunderstorms, crickets, music, greetings in different languages.
Voyager 1 is the human made object that is further away from Earth 141 AU. We expect to lose contact by 2025 then it will continue its trip until it reaches the Oort Cloud (the theoretical limit of our Solar System) for 300 more years. It is not aimed to any particular star, but in 40000 years it'll pass by -1.6 light years- the star Gliese 445. These probes are, messages in a bottle thrown into the space ocean.
I see a LOT of messages sent out, but... What will we do when we get a response?