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The Impact of Kepler on the Chances to detect Extra-terrestrial Life. SETI in the Kepler era. Are we alone?. The SETI era: 1960 Searching Extra Terrestrial Intelligence The exo -planet boom What has changed with Kepler ?. How frequent is extra-terrestrial life?.
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The Impact of Kepler on the Chances to detect Extra-terrestrial Life SETI in the Kepler era ILASOL 2011 Amri Wandel, HUJI
Are we alone? • TheSETI era: 1960 • Searching Extra Terrestrial Intelligence • The exo-planet boom • What has changed with Kepler? ILASOL 2011 A. Wandel
How frequent is extra-terrestrial life? ILASOL 2011 A. Wandel
How many civilizations exist in our Galaxy ? ? Kepler 20e,f 19.12.2011 ? Kepler 22b 5.12.2011 1011 stars 10% Sunlike Planets in HZ Earthlike nHZ ILASOL 2011 A. Wandel
Planetary disks in Orion עוברי כוכבים ו”מערכות שמש” בערפילית אוריון ILASOL 2011 A. Wandel
The Doppler method 51 Peg ILASOL 2011 A. Wandel
The transit method The inclination must be very close to 90° ILASOL 2011 A. Wandel
HD209458 • Planet mass • Planet radius • Planet density ILASOL 2011 A. Wandel
CoRoT Darwin SIM Kepler Observatories in Space ILASOL 2011 A. Wandel
Sensitivity of exo-planet projects • Radial velocity (Doppler) • Transit • Micro-lensing ILASOL 2011 A. Wandel
The Kepler mission Search Earthlike exo-planets ILASOL 2011 A. Wandel
How many civilizations are in the Galaxy ? 1011 stars in MW 10% Sunlike ?Planets in HZ ?? Earthlike nHZ fb Lifetime ILASOL 2011 A. Wandel
The Drake parameters R* ~ 10 yr -1star formation rate in the Galaxy • Fs– fraction of stars suitable for life • Fp– fraction of stars with planets • Fe – fraction of Earthlike planets • np - average # of planets in star’s HZ • Fb - probability for evolution of biology ? • Fi - probability for evol. of intelligence ?? • L - average longevity as radio-civilizations ??? ILASOL 2011 A. Wandel
The Drake equation N= R*xFsx FpxFE xnhzxFbx Fix L astronomical factors bio-social factors RE - formation rate of habitable Earth-like planets RE= R* xFs x Fpx FE x nhz = 10x0.1x 1 x 1 x 1= 1(optimist) = 10x0.1x 0.1x0.1x 0.1=0.001(pessimist) N =REx FbxFix L ILASOL 2011 A. Wandel
The 3 unknown factors Fbx Fi x L • Fb– evolution of life (biology) ~1? • Fi– evolution of intelligence (civilization with radio technology) <<1? • L – average lifetime of communicative (radio) civilization <10,000 yr? Example: Fb=100%, Fi=1%L=10,000 yrs If RE~1N~1x0.01x10,000= 100 ILASOL 2011 A. Wandel
Earthlike planets rare: N = 0.001 x Fi x L ILASOL 2011 A. Wandel
Earthlike planets frequent: N = 1 x Fi x L ILASOL 2011 A. Wandel
Probability for a civilization within 100 ly Log N or Log L/Fic (REFb=1) ILASOL 2011 A. Wandel
SETI – Serch of Extra-Terrestrial Intelligence ILASOL 2011 A. Wandel
SETI What do we search? Artificial radio-signals (leakage) of extra-Terrestrial origin Why? We assume other Civilizations use radio waves for communication like we do How? Radio-telescopes- giant dishes and arrays ILASOL 2011 A. Wandel
Radio-telescope ILASOL 2011 A. Wandel
The largest radio-teolescope: Arecibo 300m dish ILASOL 2011 A. Wandel
The SETI chanses How far can we detect leakage radio signals? Arecibo targeted sensitivity – a few ly Future arrays – tens of light years If there are 10,000 civilizations in the Galaxy, the average distance between neighbor civilizations is ~1000 ly The probability that one is within 100 ly from Earth is in that case is ~1% ILASOL 2011 A. Wandel
We still don’t know if there areextra-terretrial civilizations.. We don’t even know what are the chances to detect them… ILASOL 2011 A. Wandel
..but after one year of Kepler data, the chances seem much better. ILASOL 2011 A. Wandel