Most theoretical speculations about the existence of extraterrestrial life begins with the Drake Equation and the Principle of Mediocrity. The latter states, simply, that we are not special and, not being special, life such as ours must exist elsewhere in the universe.
The Drake Equation, however, is more complicated. Nearly every fundamentalist UFOist (the hardcore UFO proponent that pushes his beliefs in extraterrestrials with a religious fervor, ignoring prosaic explanations for even the most spurious UFO events and accepting with blind faith the testimony of fellow believers) uses the Drake Equation in his argument. (I've used the masculine pronoun in my description of UFO proponents twice in this paragraph because they are almost always male). Even middle ground UFO believers and skeptics refer to this equation as evidence of the probable existence of life in other parts of the universe.
But what doesn't get discussed is the fact that there are varied opinions as to the final outcome of the equation!
Let's start with the equation itself:
<img src="http://home.earthlink.net/~ctfeagans/drake.jpg">
R* = the rate at which stars are formed in our galaxy per year
f<sub>p</sub> = the fraction of stars, once formed, that will have a planetary system
n<sub>e</sub> = the number of planets in each planetary system that will have an environment suitable for life
f<sub>l</sub> = the probability that life will develop on a suitable planet
f<sub>i</sub> = the probability that life will evolve to an intelligent state
f<sub>c</sub> = the probability that intelligent life will develop a culture capable of communication over interstellar distances
L= the time (in years) that such a culture will spend actually trying to communicate.
Drake himself viewed N as a moderate number: not too large; not too small. His argument was that communication might be possible for a moderate number of civilizations, but they would find colonization and travel expensive endeavors. Regardless of another planet's version of economic means, materials and resources would have to be expended to create ships/technology/energy to move from one place to the next.
But what the Drake Equation doesn't cover is travel to other worlds. L, as noted above, refers to the time a capable civilization will spend trying to communicate. Wouldn't actually traveling to another planet of another solar system of, potentially, another galaxy be a whole different equation?
I have some other thoughts of the Drake Equation itself, but I'll hold off for now. This just struck me as an interesting topic since it has come up several times in several threads of late.
In fact, it might be interesting to discuss each of the factors of the Equation itself in a thread such as this. "The probability that life will develop" at all on a suitable planet is an interesting topic. What about the probability that a given culture of reasonable intelligence might endure the same fallible nature as humanity: competition among each other for prestige, power, etc. that leads to war? This, after all, would be an intuitive characteristic of natural selection/survival of the fittest. What about natural disasters such as volcanoes, asteroid impacts, and disease? Why wouldn't this need to be a subfactor for f<sub>i</sub> or f<sub>c</sub>?
The Drake Equation, however, is more complicated. Nearly every fundamentalist UFOist (the hardcore UFO proponent that pushes his beliefs in extraterrestrials with a religious fervor, ignoring prosaic explanations for even the most spurious UFO events and accepting with blind faith the testimony of fellow believers) uses the Drake Equation in his argument. (I've used the masculine pronoun in my description of UFO proponents twice in this paragraph because they are almost always male). Even middle ground UFO believers and skeptics refer to this equation as evidence of the probable existence of life in other parts of the universe.
But what doesn't get discussed is the fact that there are varied opinions as to the final outcome of the equation!
Let's start with the equation itself:
<img src="http://home.earthlink.net/~ctfeagans/drake.jpg">
R* = the rate at which stars are formed in our galaxy per year
f<sub>p</sub> = the fraction of stars, once formed, that will have a planetary system
n<sub>e</sub> = the number of planets in each planetary system that will have an environment suitable for life
f<sub>l</sub> = the probability that life will develop on a suitable planet
f<sub>i</sub> = the probability that life will evolve to an intelligent state
f<sub>c</sub> = the probability that intelligent life will develop a culture capable of communication over interstellar distances
L= the time (in years) that such a culture will spend actually trying to communicate.
Drake himself viewed N as a moderate number: not too large; not too small. His argument was that communication might be possible for a moderate number of civilizations, but they would find colonization and travel expensive endeavors. Regardless of another planet's version of economic means, materials and resources would have to be expended to create ships/technology/energy to move from one place to the next.
But what the Drake Equation doesn't cover is travel to other worlds. L, as noted above, refers to the time a capable civilization will spend trying to communicate. Wouldn't actually traveling to another planet of another solar system of, potentially, another galaxy be a whole different equation?
I have some other thoughts of the Drake Equation itself, but I'll hold off for now. This just struck me as an interesting topic since it has come up several times in several threads of late.
In fact, it might be interesting to discuss each of the factors of the Equation itself in a thread such as this. "The probability that life will develop" at all on a suitable planet is an interesting topic. What about the probability that a given culture of reasonable intelligence might endure the same fallible nature as humanity: competition among each other for prestige, power, etc. that leads to war? This, after all, would be an intuitive characteristic of natural selection/survival of the fittest. What about natural disasters such as volcanoes, asteroid impacts, and disease? Why wouldn't this need to be a subfactor for f<sub>i</sub> or f<sub>c</sub>?
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