The Search for Extraterrestrial Intelligence

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The Search for Extraterrestrial Intelligence

• E.T. phone home using 10-10-220

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Goals

• How likely is intelligent life in the Universe?
• How can we find out if there is?
• How could we communicate with it?
• Should we?

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Life in the Universe

• What are the odds of intelligent life elsewhere
  in the Universe?
• How many communicating civilizations are there in
  the Milky Way?
• How do you guess?
• How do you guess the number of jellybeans in a
  jar?
• Break the problem down into things you can guess.

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The Drake Equation

• N Number of communicating civilizations in our
  galaxy right now.
• And what about the rest?

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Star Formation Rate R

• There are 100 billion stars in the Milky Way.
• The Milky Way is 10 billion years old.
• R 100 billion stars/10 billion years

R 10 /year
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Fraction with Planets fp

• What fraction of stars have planets?
• Extrasolar planet research in the last 10 years
• 76 stars are known to have at least one planet.
• 7 stars have more than one planet.
• 1 star has three planets

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Upsilon Andromedae
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Fraction with Planets fp

• What fraction of stars have planets?
• Extrasolar planet research in the last 10 years
• 76 stars are known to have at least one planet.
• 7 stars have more than one planet.
• 1 star has three planets

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Number of Earths ne

• How many habitable planets are there in each of
  these planetary systems?
• Habitable zone water should be a liquid
• Depends on star.
• No O or B
• No M
• No binaries

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Fraction with life fl

• On what fraction of habitable planets does life
  evolve?
• Look at our Solar System.
• 3 planets in habitable zone, life has evolved on
  1 (or maybe 2).

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Fraction with intelligence fi

• What fraction of life bearing planets have life
  evolve to intelligence?
• Is intelligence inevitable?

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Fraction that communicate fc

• What fraction of intelligent civilizations become
  technological enough that we could communicate?
• Is technology inevitable?
• Desirable?

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Lifetime L

• How long does a civilization last?
• Do we have time to communicate with them?
• For us L 70 years!

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Whats the Answer?

• R 10 /year
• fp 1
• ne 1/10
• fl 1/3
• fi 1
• fc 1
• L 1000 year
• N 330! ? 330 technological civilizations in the
  Milky Way, right now.
• But there are 500 billion cubic parsecs in the
  Galaxy!

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How Can We Know?

• How can we tell if there are extraterrestrial
  civilizations?
• Go visit. Is this practical?
• Look for visitors? Is there evidence?
• Look, or listen, for signals from E.T.

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SETI

• Search for Extraterrestrial Intelligence
• Several organized searches over the last 30
  years.
• Use a radio telescope to try to detect signs of
  E.T.
• Why?
• The Earth floods space with radio waves.
• TV
• Radio
• Cellular phones
• etc

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E.T. FM

• Most natural radio sources are broadband.
• Radio stations are narrowband.

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Tuning the Dial

• Nearly all searches have been looking for
  extremely narrow radio signals.
• But there are millions and billions of
  frequencies to listen to.
• And millions and billions of stars
• Concentrate on nearby sun-like stars.
• No luck.
• Point in the sky randomly.
• No luck yet. But you can help.

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SETI_at_Home

• Receiver piggybacks on Arecibo telescope.
• Constantly searches as telescope observes.
• Millions of channels.
• Thousands of hours.
• Lots of data.
• Needs lots of computer power.
• Your power.

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SETI_at_Home
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Is there anybody out there?

• We have made three attempts to communicate.
• The Arecibo broadcast to Hercules Cluster.

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Heres my card.

• 2. The Pioneer 10 and 11 plaques.

Pioneer 10 is now 9.5 billion kilometers from
Earth 8.5 light hours!
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The Voyager Record Club

• 3. Voyagers 1 and 2 contain a plaque and a record.

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• Bach, Brandenburg Concerto No. 2 in F. First
  Movement, Munich Bach Orchestra, Karl Richter,
  conductor. 440
• Java, court gamelan, "Kinds of Flowers," recorded
  by Robert Brown. 443
• Senegal, percussion, recorded by Charles Duvelle.
  208
• Zaire, Pygmy girls' initiation song, recorded by
  Colin Turnbull. 056
• Australia, Aborigine songs, "Morning Star" and
  "Devil Bird," recorded by Sandra LeBrun Holmes.
  126
• Mexico, "El Cascabel," performed by Lorenzo
  Barcelata and the Mariachi México. 314
• "Johnny B. Goode," written and performed by Chuck
  Berry. 238
• New Guinea, men's house song, recorded by Robert
  MacLennan. 120
• Japan, shakuhachi, "Tsuru No Sugomori" ("Crane's
  Nest,") performed by Goro Yamaguchi. 451
• Bach, "Gavotte en rondeaux" from the Partita No.
  3 in E major for Violin, performed by Arthur
  Grumiaux. 255
• Mozart, The Magic Flute, Queen of the Night aria,
  no. 14. Edda Moser, soprano. Bavarian State
  Opera, Munich, Wolfgang Sawallisch, conductor.
  255
• Georgian S.S.R., chorus, "Tchakrulo," collected
  by Radio Moscow. 218
• Peru, panpipes and drum, collected by Casa de la
  Cultura, Lima. 052
• "Melancholy Blues," performed by Louis Armstrong
  and his Hot Seven. 305
• Azerbaijan S.S.R., bagpipes, recorded by Radio
  Moscow. 230
• Stravinsky, Rite of Spring, Sacrificial Dance,
  Columbia Symphony Orchestra, Igor Stravinsky,
  conductor. 435
• Bach, The Well-Tempered Clavier, Book 2, Prelude
  and Fugue in C, No.1. Glenn Gould, piano. 448
• Beethoven, Fifth Symphony, First Movement, the
  Philharmonia Orchestra, Otto Klemperer,
  conductor. 720
• Bulgaria, "Izlel je Delyo Hagdutin," sung by
  Valya Balkanska. 459

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And if they answer?

• Should we be listening for E.T.?
• Should we be trying to contact E.T.?
• What if we do?
• What can we say?
• What can we learn?
• What do we have to fear?
• How will we be changed?
• Contact.