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THE FERMI PARADOX

THE FERMI PARADOX. Where are the little green men?. FERMI SPECULATES. At Los Alamos in the summer of 1950, Enrico Fermi, Edward Teller, and Herbert York speculate: The universe is very old. There are billions of stars in billions of galaxies.

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THE FERMI PARADOX

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  1. THE FERMI PARADOX Where are the little green men?

  2. FERMI SPECULATES • At Los Alamos in the summer of 1950, Enrico Fermi, Edward Teller, and Herbert York speculate: • The universe is very old. • There are billions of stars in billions of galaxies. • The law of large numbers indicates that extraterrestrial life should not be rare. • “SO? WHERE IS EVERYBODY?”

  3. Life does not exist “out there” • Life’s genesis is rare. • Multicellular life may be exceedingly rare. • Intelligence/tool making is rare. • Language is unique to humans. • Technology/science is not inevitable.

  4. Intelligent aliens do not exist (and never did). • An inhospitable universe destroys complex intelligent life. • It is the nature of intelligent life to destroy itself. • It is the nature of intelligent life to destroy others. Berserker probes developed by aggressive aliens seek out and destroy civilizations. • God created humans alone.

  5. Planets with the right conditions for life are rare. • “Rare Earth hypothesis” • Solar system location in the galaxy shields us from radiation. • Our very large moon stabilizes the earth’s orbit. • Tidal stresses cause a magnetic field which protects us from radiation. • Proper distance from the sun with atmosphere and liquid water. • Jupiter “broom” protects us from impacts.

  6. Life exists “out there” • If life is possible at all in the universe – then given the vast scale and age of the universe, it is almost certain that extraterrestrial life exists (Drake Equation). • The anthropic principle notes that the universe seems uniquely suited to the development of human intellegence.

  7. The Drake equation (1960’s) • N=(R*)(fp)(ne)(fl)(fi)(fc)(L) • The Drake Equation, named after its creator, radio astronomer Frank Drake, is an attempt to frame the question scientifically by assigning a value to all the relevant terms.

  8. R* is the rate of star formation in our galaxy.

  9. Fp is the fraction of stars which have planets.

  10. Ne is the average number of planets with potential to support life.

  11. Fl is the fraction which actually develop life.

  12. Fi is the fraction which actually develop intelligent life.

  13. Fc is the fraction willing to communicate.

  14. L is the expected lifetime of the civilization.

  15. Drake’s Solution • The variables in the Drake Equation are highly speculative. • Drake’s values yield 10,000 civilizations in our galaxy. • If one or more of the terms is small, then the number could shrink to only one (Our civilization).

  16. Aliens exist but have not yet communicated. • They have not had time to reach us. Speed of light slows communication. Relativity makes space travel take too long. • They are signaling but we don’t know how to listen. • They have no desire to communicate with primitive life forms (us). • They do not communicate with us because of ethical reasons. • Their psychologies or physiologies may simply be too different to communicate with us.

  17. Aliens are here on Earth! • They were here and left evidence (pyramids, Atlantis etc.) . • They are us. Humans are descendents of aliens. • We are the result of their “contamination” (Panspermia). • Zoo hypothesis – they are keeping us in a well designed zoo for study etc. • Interdiction treaty keeps them from contacting young races (us).

  18. They visit us regularly (UFO’s). • The aliens are cloaked. • They visit to study us w/o interference. • They visit to experiment (alien abductions wars, pandemics etc.). • We are for their amusement (pets).

  19. We are looking for them! • Searching is limited by great distances. • The dangers of anthropomorphism. • We look for radio emissions (SETI). • We look for direct planetary observations (exoplanet hunters). • We look for alien constructs (probes, colonies, or artifacts (Dyson spheres). • What have we found? • NOTHING !

  20. We are signaling them. • Pioneer 10 was launched on 2 March 1972. • Pioneer 11 was launched on 5 April 1973. • First man made objects to leave the solar system • Pioneer plaque.

  21. The Golden Record • Voyager I launched on September 5, 1977. • Voyager II launched on August 20, 1977. • Explains the origin of the spacecraft. • 115 images and a variety of natural sounds. • spoken greetings in many languages.

  22. We are sending radio signals (Arecibo message ) • Beamed into space in 1974. • Aimed at the globular star cluster M13 some 25,000 LY away. • 1679 binary digits.

  23. We are leaking signals to space. • TV shows from the 50’s are now 5,860,000,000,000 mi. “out there”. • WHAT WILL THEY THINK OF US?

  24. Can They See Our Lights?

  25. WHAT DO YOU THINK? • PBS Nova Poll results: • 16% think that we are alone in the universe. • 77% think that there is other intelligent life somewhere in the universe. • 7% undecided.

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