Countdown für die Ewigkeit: In 1980, the American professor Thomas A. Sebeok received a call that took him by surprise. He was to participate in a crisis team of the Bechtel corporation. This assembly of renowned scientists was concerned with the question of what should be done with the now accumulated quantities of radioactive waste from military and civilian use. One task was to develop notification systems that would still be able to warn of the dangers of radioactive substances 10,000 years from now.