SETI

1
SETI
2
Extra Terrestrial Intelligence

• Is there intelligent life on other planets?
• If so,
• Can we find them?
• Can we try to communicate?
• SETI is the Search for Extra Terrestrial
  Intelligence

3
Evolution of Intelligence

• If a planet has life, will intelligence evolve?
• Within the last 2 million years on Earth
• Less than 1/1000 the time since life appeared
• How probable is the development of technology?
• Radio communications for just 100 years
• Less than 1/10,000 the time since humans appeared
• How long will an intelligence survive?

4
Drake Equation

• In 1960 Frank Drake created a way to estimate the
  number of planets with civilizations capable of
  interstellar communication.
• The Drake equation
• Rate in years

• R 1 rate of stars forming
• fp 1 fraction with planets
• ne 0.1 earth-like planets
• fl 1 fraction with life
• fi 1 intelligence fraction
• fc 1 communicating aliens
• L 100 lifetime of civilization
• Total 10 in the galaxy

5
Communicating with ET

• Sending a spaceship is too slow (25,000 mph 11
  km/s).
• 300,000 years to reach the nearest star
• Radio communication is much faster (300,000
  km/s).
• 4 years to the nearest star
• Earth radio to stars within 100 light years
• A planet 60 ly away could be watching I Love
  Lucy.

6
Searching for Signals

• Civilizations may also be sending information.
• Radio waves (including TV) are easy to detect.
• Radio telescopes scan the sky for radio objects.
• Searches analyze data in parallel with other
  experiments.

7
SETI _at_ Home

• Data must be scanned for signals.
• Weak signals, lots of noise
• Needs lots of computer time
• SETI_at_home uses volunteer computers.
• So far, the fluctuations seem to be random.