Theme 12 SETI: Looking for ET ASTR 101 Prof. Dave Hanes III. Passive Contact We wait for ET visitors to come here, to provide a completely persuasive and credible first contact UFOs? Caveat emptor! UFO sighting, ET abductions, etc: many of these reports are misguided (although sincere); others are simply logically inconsistent and unpersuasive and sometimes fraudulent (e.g. the Roswell alien autopsy film). Remember Carl Sagans remark on the astonishing banality of reported contacts. (Why crop circles?) A Claimed Message from ET [is this really a likely first contact?] " If the Earthlings should not raise their vibratory rate within a set period of time, severe earth changes and major cataclysms will take place. " If the Earthlings should not raise their vibratory rate within a set period of time, severe earth changes and major cataclysms will take place. Such disasters will not end the world, but shall serve as cataclysmic crucibles to burn off the dross of unreceptive humanity. Such disasters will not end the world, but shall serve as cataclysmic crucibles to burn off the dross of unreceptive humanity. Those who die in such dreadful purgings will be allowed to reincarnate on higher levels of development so that their salvation will be more readily accomplished through higher teachings on a higher vibratory level." Those who die in such dreadful purgings will be allowed to reincarnate on higher levels of development so that their salvation will be more readily accomplished through higher teachings on a higher vibratory level." Contact is Not Impossible: Consider Stellar Ages The Sun (and Solar System) formed 4.6 billion years ago. But many billions of stars formed in the Galaxy long before that! (The very oldest are ~10-11 billion years old.) Many civilizations could have sprung up literally billions of years ago. Even given the challenges, they could have slowly migrated through the galaxy. So its not impossible that visitors could reach us. Fermis Question: Where Are They? Some possible answers: The zoo hypothesis (they are watching us with vague interest, treating us like interesting animals in a zoo) The zoo hypothesis (they are watching us with vague interest, treating us like interesting animals in a zoo) The benevolent observer hypothesis (they are watching us, ready to intervene if we do something really self-destructive) The benevolent observer hypothesis (they are watching us, ready to intervene if we do something really self-destructive) The too many to care hypothesis (there are so many life forms in the galaxy that no one cares about just one more; they are content to leave us to our own devices) The too many to care hypothesis (there are so many life forms in the galaxy that no one cares about just one more; they are content to leave us to our own devices) The they are among us hypothesis (aliens are here and intermixed in the human population, in disguise) The they are among us hypothesis (aliens are here and intermixed in the human population, in disguise) The philosopher hypothesis (few if any of the ET societies can be bothered to explore, as we seem driven to do) The philosopher hypothesis (few if any of the ET societies can be bothered to explore, as we seem driven to do) The singular hypothesis (life is so rare or so chancy in the universe that we may be almost literally unique in our galaxy) The singular hypothesis (life is so rare or so chancy in the universe that we may be almost literally unique in our galaxy) IV. Passive Communication We hunt for clear electromagnetic evidence of ETs (not necessarily as messages sent out for the purpose of making contact) Such searches are now being carried out with radio telescopes: the SETI project. This is a very special time: we could have a positive answer to this issue in our lifetimes. (A negative simply leaves the question open. We cant prove they dont exist!) LGM? The Search Itself We need to define: The list of potential targets [thats easy! there are lots of sun-like stars] The list of potential targets [thats easy! there are lots of sun-like stars] The wavelength at which we will look The wavelength at which we will look What signal (non-natural structure) we will look for What signal (non-natural structure) we will look for What Wavelength? Originally: Something universal, significant to all intelligent and curious species. One example: the 21-cm natural radiation of neutral hydrogen gas, which is abundant. This is less a problem now: we can sweep across the spectrum. What Signature? Exactly what characteristics should we be looking for to identify the signal as non-natural and definitely the product of some intelligence? Thats not easy to say! (In the movie Contact, the incoming signal contains the prime numbers repeated over and over. That would work, but assumes that ET is trying to catch our attention. Of course we are also hoping to eavesdrop.) Success? Wow! (Maybe) Join the Hunt! SETI scans trillions of wavelengths, with sophisticated pattern-recognition software You can join the exercise! Maybe the key discovery will be made on your computer! Final Questions to Ponder If we do make contact with ETs: What would you ask them? What would you ask them? What would we be proud to tell them? What would we be proud to tell them? What would we be less ready to disclose? What would we be less ready to disclose? What impact would such a discovery have on society, religion, science and you? What impact would such a discovery have on society, religion, science and you? Either We Are Alone, or We Arent . whichever it is, it is a very profound thought. A Pale Blue Dot Looking Back from Voyager to the Earth A Pale Blue Dot Looking Back from Voyager to the Earth Carl Sagans Words Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. there is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.