The Drake Equation

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The Drake Equation

• Calculating the possibility of life

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A 360º photo of the Milky Way seen from Death
Valley, USA.
Image and more details may be found at
http//antwrp.gsfc.nasa.gov/apod/ap070508.html
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Is there life out there?

• Since the 1960s astronomers have been trying to
  work out the probability of contacting
  extra-terrestrial life.
• To work out the overall probability we need to
  guestimate the probability of a number of
  factors occurring.

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R,the rate of formation of stars in our galaxy
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fp, the fraction of stars that have planets
around them
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ne, the number of suitable planets in each
planetary system
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fl the fraction of suitable planets which
develop life
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fi the fraction of life-bearing planets which
develop intelligent life
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ft the fraction of intelligent life bearing
planets which develop technology
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L, the length of time the civilisation releases
signals into space
What if theyve already tried to contact us and
we missed the call?
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The Drake Equation

• To work out the number of civilisations in our
  galaxy with whom we might have a hope of
  communicating we multiply all these factors
  together.

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• Different astronomers and cosmologists use
  different values for each of these factors.
• However, it is generally thought that there is a
  finite chance of contacting extraterrestrial
  intelligent beings.