Life In The Universe?

The Drake equation was written in 1961 by astrophysicist Frank Drake to estimate the number of intelligent civilizations in the Milky Way galaxy. The equation summarizes the main concepts which scientists must contemplate when considering the question of other communicative life.

The Drake equation is: # = R x P x L x D x C x S x T
# = the number of civilizations in our galaxy with which communication might be possible
R = the average Rate of star formation in our galaxy
P = the fraction of those stars that have Planets
L = the average number of planets that can potentially support Life per star that has planets
D = the fraction of planets that could support life that actually Develop life at some point
C = the fraction of planets with life that actually go on to develop Civilizations
S = the fraction of civilizations that develop a technology that releases detectable Signs of their existence into space
T = the length of Time for which such civilizations release detectable signals into space

The ‘educated guesses’ used by Drake and his colleagues in 1961 were:
R = 1 (1 star formed per year, on the average over the life of the galaxy)
P = 0.2 to 0.5 (one fifth to one half of all stars formed will have planets)
L = 1 to 5 (stars with planets will have between 1 and 5 planets capable of developing life)
D = 1 (100% of these planets will develop life)
C = 1 (100% of which will develop intelligent life)
S = 0.1 to 0.2 (10–20% of which will be able to communicate)
T = 1000 to 100,000,000 (which will last between 1000 and 100,000,000 years)

Inserting the above minimum numbers into the equation gives a minimum of 20 civilizations.
Inserting the maximum numbers gives a maximum of 50,000,000.

Drake’s original meeting concluded that there were probably between 1000 and 100,000,000 civilizations in the galaxy.

The Drake equation can give a very wide range of values, depending on the assumptions, as the values used by Drake are not well established. The result can be # ≪ 1, meaning we are likely alone in the galaxy, or # ≫ 1, implying there are many civilizations. The presence of humanity implies a probability of intelligence arising of greater than zero. (Assuming that humanity is actually intelligent).

Comments | 11

  • Chances

    NASA estimates that the Milky Way is made up of approximately 100 billion stars. If 25% of them have planets, that’s 25 billion. Our sun has 9 planets. Let’s say the average is 4. That’s 100 billion. If only one of them is Earth-like, that’s 25 billion.
    25 billion Earth-like planets. Maybe 1 in 10 has “Goldilocks” conditions (not too hot, not too cold) that’s still 2 ½ billion.
    With that many possibilities, it’s harder to believe that none of them has intelligent life than it is to believe the opposite.
    The chances of life beyond Earth are extremely high.

    • Chances are that we won't be here very long

      Now we could also predict where the stock market would be in 50 years, it is not predictable, not even this afternoon. We exist and that is for this very fleeting moment, we are here, as conscious beings within civilizations that have been here for at the most 50,000 years, which is like one millionth of the beat of an eyelash in terms of the life of the Universe. There are at least one hundred billion galaxies if not five times that number in the Universe. How many planets within these galaxies are precisely at the point in civilization where human beings are at this precise moment in time? Impossible to every know for certain. I would say five, all teetering on the edge of extinction, that’s just a wild guess. We exist, our Planet Earth, within a speck of dust within the Universe. We shouldn’t have this idea that it’s amazing and incredible, but that it is just, according to the numbers, an extraordinarily random possibility of a very insignificant occurrence.

    • Phptographs???

      Based on studies like Drake’s equation, the probability is high. Expressed as a percentage, its 99.99 (followed by a whole lot more 9’s), in other words, a virtual certainty.
      That being the case, why are there not any certifiably genuine photographs of any of them?

  • Chances

    Of course one has to take into account how many years a civilization will last before it either self-destroys or is wiped out by a cosmic event. When you consider our civilization is at best 100000 years old and our technology is less than 200, compared to the 13 billion years of the universe, there have probably been many civilizations that have come and gone. The number that co-exist with us during our time in the cosmos would likely be limited

  • I can increase that number

    Next, we multiply by infinity, to account for the multiverses.

  • Chances

    Or zero if we all exist in the toy box of another being

  • Non-sequitor

    My father once told us that all Fagelsons are related. I have found them all over the country but nowhere near Troy. Thanks, I’ll have to look into it.

  • I depends

    Of course, it also depends on our definition of “intelligent.” Perhaps there are none that qualify.

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