Will We Be Discovered?
Two Voyager spacecrafts are on their way out into interstellar space. They are carrying a message from humanity in the form of a golden record with pictures, music and speech from many different cultures. Carl Sagan was responsible for collecting the material and tells the story in his interesting book "Murmurs From Earth". Among other things he was able to get the then active UN ambassadors to record greetings. Most of them had to be heavily edited but the recording by Anders Thunborg of the poem "Visit to an Observatory" by Swedish Nobel laureate Harry Martinson was kept in its entirety and gives a very moving impression.
The spacecrafts have the potential to survive for millions of years and may well in the far future reach other stars, although they travel at the snail's pace, as seen from an astronomical perspective. That some other intelligent civilisation would ever come in their way is not very probable. Other messages, in the form of radio signals are also transmitted. Some symbolic, others unintentional and still others with the expressed intention to generate contact with another civilisation. Some scientists and debaters mean that this can be a potential danger for mankind. Among them are the cosmologist Stephen Hawking and science fiction writer David Brin.