The Search for Extraterrestrial Intelligence

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# The Search for Extraterrestrial Intelligence - PowerPoint PPT Presentation

The Search for Extraterrestrial Intelligence. E.T. phone home using 10-10-220. 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?. Life in the Universe.

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## The Search for Extraterrestrial Intelligence

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### The Search for Extraterrestrial Intelligence

E.T. phone home using 10-10-220

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?
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.
The Drake Equation

N = Number of communicating civilizations in our galaxy right now.

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

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

fp = 1

Optimistic!

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

ne = 1/10

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

fl = 1/3

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).

fl = 1

Inevitable!

Fraction with intelligence: fi
• What fraction of life bearing planets have life evolve to intelligence?
• Is intelligence inevitable?

fl = 1

Inevitable!

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

L = 1000 years

Optimistic?

• How long does a civilization last?
• Do we have time to communicate with them?
• For us: L = 70 years!
• 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!
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.
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
• Cellular phones
• etc
E.T. FM
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.
SETI@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.
“Is there anybody out there?”

We have made three attempts to communicate.

• The Arecibo broadcast to Hercules Cluster.
Here’s my card.

2. The Pioneer 10 and 11 plaques.

Pioneer 10 is now 12 billion km from Earth – 80 AU  11.3 light hours!

The Voyager Record Club

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

Bach, Brandenburg Concerto No. 2 in F. First Movement, Munich Bach Orchestra, Karl Richter, conductor. 4:40
• Java, court gamelan, "Kinds of Flowers," recorded by Robert Brown. 4:43
• Senegal, percussion, recorded by Charles Duvelle. 2:08
• Zaire, Pygmy girls' initiation song, recorded by Colin Turnbull. 0:56
• Australia, Aborigine songs, "Morning Star" and "Devil Bird," recorded by Sandra LeBrun Holmes. 1:26
• Mexico, "El Cascabel," performed by Lorenzo Barcelata and the Mariachi México. 3:14
• "Johnny B. Goode," written and performed by Chuck Berry. 2:38
• New Guinea, men's house song, recorded by Robert MacLennan. 1:20
• Japan, shakuhachi, "Tsuru No Sugomori" ("Crane's Nest,") performed by Goro Yamaguchi. 4:51
• Bach, "Gavotte en rondeaux" from the Partita No. 3 in E major for Violin, performed by Arthur Grumiaux. 2:55
• Mozart, The Magic Flute, Queen of the Night aria, no. 14. Edda Moser, soprano. Bavarian State Opera, Munich, Wolfgang Sawallisch, conductor. 2:55
• Georgian S.S.R., chorus, "Tchakrulo," collected by Radio Moscow. 2:18
• Peru, panpipes and drum, collected by Casa de la Cultura, Lima. 0:52
• "Melancholy Blues," performed by Louis Armstrong and his Hot Seven. 3:05
• Azerbaijan S.S.R., bagpipes, recorded by Radio Moscow. 2:30
• Stravinsky, Rite of Spring, Sacrificial Dance, Columbia Symphony Orchestra, Igor Stravinsky, conductor. 4:35
• Bach, The Well-Tempered Clavier, Book 2, Prelude and Fugue in C, No.1. Glenn Gould, piano. 4:48
• Beethoven, Fifth Symphony, First Movement, the Philharmonia Orchestra, Otto Klemperer, conductor. 7:20
• Bulgaria, "Izlel je Delyo Hagdutin," sung by Valya Balkanska. 4:59
• Navajo Indians, Night Chant, recorded by Willard Rhodes. 0:57
• Holborne, Paueans, Galliards, Almains and Other Short Aeirs, "The Fairie Round," performed by David Munrow and the Early Music Consort of London. 1:17
• Solomon Islands, panpipes, collected by the Solomon Islands Broadcasting Service. 1:12
• Peru, wedding song, recorded by John Cohen. 0:38
• China, ch'in, "Flowing Streams," performed by Kuan P'ing-hu. 7:37
• India, raga, "Jaat Kahan Ho," sung by Surshri Kesar Bai Kerkar. 3:30
• "Dark Was the Night," written and performed by Blind Willie Johnson. 3:15
• Beethoven, String Quartet No. 13 in B flat, Opus 130, Cavatina, performed by Budapest String Quartet. 6:37
A Pale Blue Dot

43 AU

Credit – Voyager 1990