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SETI: the Search for Extraterrestrial Intelligence
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What we will look at… Overview of the topic Overview of the topic Brief review of exploration in our solar system Brief review of exploration in our solar system The problem of SETI—the search for extraterrestrial intelligence The problem of SETI—the search for extraterrestrial intelligence Historical, current and planned searches Historical, current and planned searches Efforts to transmit Efforts to transmit Why have we not found ET? Why have we not found ET?
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The search for respectability International Astronomical Union created a Commission on ETL in 1982
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Long of Interest Poster from 1800-01
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Intelligent Life Here?
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Venus too hot?
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Our Moon
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Mars
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Arm scooped soil and placed in growth chambers Results: nothing certain
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Life from Mars? Current Rovers looking for water…
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Jupiter or Saturn?
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Maybe on one of the moons?
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Beneath the ice on Europa?
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Beyond our Solar System: we turn to the stars…
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Can they exist?
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How does life begin? The Miller-Urey Experiment
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Beta Pictoris: early evidence of other solar nebulae
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Other planets? Now more than 200
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We will look in the radio—why?
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The “Water Hole”
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First search at Greenbank, WV …
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… Project Ozma 1960 200 hours observing two nearby solar stars in 21-cm nothing found but a secret satellite
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85-ft Harvard Dish Paul Horowitz
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Suitcase SETI
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NASA thinks big: Cyclops Details…
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A thousand 100-meter dishes detect ET’s broadcast, if within 100 ly (>6,000 stars) ~5 billion $
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NASA’s nemesis William Proxmire, Senator from Wisconsin Golden Fleece Awards Called off by Carl Sagan
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NASA’s initial hardware
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Software: see a pattern? This is a plot of signal (intensity of dots) in frequency vs. time
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Here it is
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A test: detection of Pioneer 10 But—Congress killed NASA’s SETI project…
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First Intentional Transmission
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The signal: digital Let’s look at why digital …
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Digital advantage sketch…
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Graphical The message consists of 1679 bits, arranged into 73 lines of 23 characters per line (these are both prime numbers, and may help the aliens decode the message). It consists, among other things, of the Arecibo telescope, our solar system, DNA, a stick figure of a human, and some of the biochemicals of earthly life. For less than 3 minutes it was the brightest source in the MWG at that frequency.
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Target: M13 (30,000 ly…)
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Unintentional Transmissions: broadcast TV
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Pioneer 10 & 11 Plaques (1972-3)
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Voyager Record: “Best of Earth”
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Images and Sounds “Best of Earth” Narrated by Kurt Waldheim, then U.N. Secretary General and now (embarrassingly..) friend of fellow Austrian Aaaaanold….
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NASA: Take the Search to Space
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SETI@home Windows > 2000 – beware…
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“Parasitic” observations at Aricebo Telescope
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Allen Array 350 6.1-m dishes 350 6.1-m dishes 1 – 10GHz (the “water hole”) 1 – 10GHz (the “water hole”) Artist concept Artist concept Funded by Microsoft co-founder Paul Allen (and COB, Charter Communications) Funded by Microsoft co-founder Paul Allen (and COB, Charter Communications) Newer, offset Gregorian design Newer, offset Gregorian design
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SETI Inspired Carl Sagan’s Contact Ellie Arroway (Jodi Foster) loosely based on (real) Jill Tarter, former head of NASA SETI
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Fermi: “Where is everybody?”
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Would not be complete without mention
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