Astronomy Professor Jason Wright (Pa.) Has released material whose main purpose is to find out if we have tried enough to search for extinct alien life - especially intelligent forms. He asks if we continue to look for those forms (technosignals) that are no longer there, but could leave behind evidence of existence in the past.
Wright does not assure that the alien life existed 100%, but he is convinced that in a deep search you need to include life forms that were near, but disappeared in a certain time period. He notes that most of today's missions related to the search for life outside the Earth, focused on the detection of biosignals - evidence for living organisms, and not possible dead remains. He noted that it is difficult to find such evidence on Earth due to the presence of weather and tectonic activity. But in the solar system there are objects that not only remain unchanged, but are also protected from radiation effects and asteroid attacks. Among them may be not only the planets, but also asteroids and satellites.
The author believes that it is necessary to take seriously the search for technosignals, both on Earth (in the rocks with a million or billions in age), and other celestial bodies of the solar system.