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Class 10: Water/Life on Other Planets. Astrobiology. 1.7. Billion years ago. 3.75. 4.5. Billion years ago. Billion years ago. 600. 500. 225. Million years ago. Million years ago. Million years ago. Life’s Sequence on Earth. Life As We Know It. Conditions for Life (I).
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Class 10: Water/Life on Other Planets
1.7 Billion years ago 3.75 4.5 Billion years ago Billion years ago 600 500 225 Million years ago Million years ago Million years ago Life’s Sequence on Earth
Conditions for Life (I) Liquid water
Conditions for Life (II) Carbon
Conditions for Life (III) Energy
Conditions for Life (IV) Stable Environment
The Drake Equation Nc = N* x fp x nLZ x fL x fI x Fs = # of communicative civilization in galaxy Pessimistic Estimate Optimistic Estimate N*= # stars in galaxy 2x1011 2x1011 fp = fraction of stars w/planets 0.01 0.5 nLZ = number of planets in habitable zone 0.01 1 fL = fraction of planets where life could begin 0.01 1 fI = fraction of life forms that evolve to intelligence 0.01 1 Fs = fraction of star’s life where life communicates 10-8 10-4 Nc = 2x10-5 10x106 • Pessimist: we are alone • Optimist: many civilizations
(SETI) SETI Institute Aricebo Search for Extraterrestrial Intelligence
• Project Phoenix: primary search, nonprofit, $20M • SERENDIP: piggyback search of ordinary astronomy data • seti@home: SETI Projects Jill Tarter - 2.3 million users, - 1000 yrs computer time each day
Effelsberg Big Ear Haystack Square Kilometer Array Arecibo SETI Telescopes