Free Astronomy Magazine March-April 2023

MARCH-APRIL 2023 ASTRO PUBLISHING Since that distant summer, sci- entists and free thinkers have proposed dozens of plausible but hypothetical solutions to the Fermi paradox. Most of them imply an extreme rarity of technological civilizations in the Milky Way, the lack of will to communicate with other civ- ilizations, and the difficulty of receiving and, above all, trans- mitting interstellar messages. These scenarios are well suited to the total absence of positive results obtained by the numer- ous SETI programs conducted since the 1960s. The seemingly most obvious so- lution to the Fermi paradox is that we have no evidence that other technological civiliza- tions exist simply because those civilizations do not exist. As we currently understand processes in the universe, we can assume that the first civilizations capa- ble of communicating with other planets could have man- ifested themselves as early as seven-to-eight billion years ago. If they had appeared in our galaxy, they would have had time to colonize it far and wide, leaving behind traces of their existence, recognizable even long after the eventual disappearance of those same civilizations. Since nothing of the sort has been found so far, either those civilizations didn’t exist, they didn’t exist for long enough, or they weren’t inter- ested to leave lasting testi- monies. If they have survived long enough to be our contem- poraries and are aware of our existence, perhaps they are de- liberately ignoring us. How- ever, this puts a restriction on their number because, in order for them all to agree to ignore us, they must be relatively few. Technosignatures for detecting intelligent life in our Universe — A research companion The book summarizes the multiple interdisciplinary efforts that have contributed to the field of technosignatures. The tech- nosignatures represent any signals that can be collected from the Universe, such as radio wavelengths, optical signals, and many more, that can be potential candidates as signals emitted intentionally from another part of the Universe that is not Earth. It shows how current advances in science, technology, and social sciences can support this effort and can be used as both a resource for the scientists in the field and as a refer- ence for the public at large interested in the topic. More than us — Discover how we are going to find life in the Universe Humans have thought about this question for millennia. Only recently have we developed the technology to actually search for life in the universe. In this book, you will discover how we are going to find it! We will look at questions like: • Where to search for extraterrestrial life? • Why haven’t we heard from anybody yet? • Should we send signals ourselves? • What efforts have been made to find life in the cosmos? • What happens if a signal is detected? The hunt for alien life — A wider perspective Astronomer Peter Linde takes the reader through the story of the search for extraterrestrial life in a captivating and thought- provoking way, specifically addressing the new research that is currently devoted towards discovering other planets with life. He discusses the methods used to detect possible signals from other civilizations and the ways that the space sciences are changing as a result of this new field. Here, Linde tries to an- swer many philosophical questions that derive from this area of research: Is humanity facing a change of paradigm, that we are not unique as intelligent beings? Is it possible to communi- cate with others out there, and even if we can — should we? Rare Earth — Why complex life is uncommon in the Universe What determines whether complex life will arise on a planet, or even any life at all? Questions such as these are investigated in this groundbreaking book. In doing so, the authors synthesize information from astronomy, biology, and paleontology, and apply it to what we know about the rise of life on Earth and to what could possibly happen elsewhere in the universe. Every- one who has been thrilled by the recent discoveries of extraso- lar planets and the indications of life on Mars and the Jovian moon Europa will be fascinated by Rare Earth, and its implica- tions for those who look to the heavens for companionship.