This debate is an old one but a few weeks ago this year, it reignited at the annual meeting of the American Association for the Advancement of Science, held in San Jose. It was discussed the opportunity of the so called “Active SETI”, which means the Search for Extraterrestrial Intelligence, planned more than 50 years ago. “In the past we’ve always assumed that any extraterrestrial civilization with the capacity to detect us will automatically take the initiative to make contact, sending us a powerful signal to let us know they exist. But there may be civilizations out there that refuse to reveal their existence unless we make it clear that we want to make contact,” said Douglas Vakoch of the SETI Institute in Mountain View, California. The dilemma is linked to the proactive transmissions of radio signals from the Earth program. Many participants at such discussions issued warning about the risks, assuming that not all of the other potential civilizations are thinking friendly in the hypothesis of the contact.