Use the Drake equation to calculate the potential for intelligent life within our Galaxy. Your teacher may assign different numbers to use than the suggested ones in bold, or different groups may work independently with their own assumptions.

N = R* • fp • ne • fl • fi • fc • L

• N = The number of civilizations in the Milky Waygalaxy whose electromagnetic emissions are detectable.
• R* =The rate of formation of stars suitable for the development of intelligent (Say…0.05, 5%)
• fp= The fraction of those stars with planetary systems.  (50%, or 0.50)
• ne= The number of planets, per solar system, with an environment suitable for life.  (Difficult to say; maybe 1 as in our case)
• fl= The fraction of suitable planets on which life actually appears.  (This is hard to assign a number; see below##)
• fi= The fraction of life bearing planets on which intelligent life emerges. (1.0, 100%, why not, eh?)
• fc= The fraction of civilizations that develop a technology that releases detectable signs of their existence into space. (Again, see ##Special Considerations below)
• L = The length of time such civilizations release detectable signals into space. (We have for 100 years or out Earth’s 4.6 billion)

## Special Considerations:

• The universe is over 13.7 billion years old.
• Our (relatively young) solar system is less than half that age at about 4.6 billion years.
• Our planet has fossils of very simple life for 3.5 billion years.
• The MWG is some 13.2 billion years old—enough to have had 2.8 solar system cycles like ours.
• Our solar system will exist for another 5 billion years before the Sun becomes a red giant.
• It takes 100,000 years for radio waves to travel across the galaxy.
• Intelligent life with technological advances to comprehend and communicate outside our solar system has existed for about a hundred years. 

In other words, during the life of the galaxy thus far, humans have had the ability to communicate outside our solar system for 100 years / 13.2 x 109, or,  .  Even if another civilization were contemporaneous with ours, they would have to be within 100 ly to have received our first radio waves by now. If they were 2,000 ly away, they would not receive our radio waves until the year 2300.  Another consideration: without the ability to travel at or faster than light speed, the time involved would be many generations in human life spans. (Of course, perhaps these intelligent beings have already discovered how to use wormholes and portals to appear at our doorstep, for good, or, as Steven Hawking thinks, for bad!)

Calculate your OWN number for the Drake equation, using and justifying values that you deem appropriate.  Then, discuss the chances that another species would have coincided with our current time line; include in the discussion the possibility that an extraterrestrial life form would be want to make contact with humans, and what that contact may look like.  You may submit your answer as a file attachment or a text entry.