Drake
Equation
Understanding the Terms:
percent of these radio technologies that are 'current'
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Since we are interest in estimating the number of alien civilizations from which we can receive signals, we only want to consider the alien civilizations who exist in a timeframe such that their radio signals can reach us while we are able to detect them.

Consider the three scenarios below and think about what the requirement of "current" means.

select a time for alien radio signals to reach the earth



Ultimately, deciding on what percent of radio technologies you believe to be current comes down to the lifespan of a civilization with radio technology. The longer civilizations have radio technology, the more radio technologies are current. Consider the selections below:
select a civilization lifespan

lifespan of a civilization with radio technology

Your current choice for this term:

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