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The Speculations of the Contact Optimists

Now, contact optimists, like theologians, can speculate. And speculate they do. Today’s star searchers can rely on a dramatic form of speculation known as the Drake equation. The Drake Equation, first formulated by Frank Drake in 1961 (National Radio Astronomy Observatory in Green Bank, West Virginia), looks like this:

N = N* fp ne fl fi fc fL where

N* = the number of stars in the Milky Way Galaxy
fp = the fraction of stars with planets around them
ne = the number of planets per star
fl = the fraction of planets in ne where life evolves
fi = the fraction of fl where intelligent life evolves
fc = the fraction of fi that communicate
fL = the fraction of the planet’s life during which communication happens
N = the number of communicating civilizations in the galaxy. (Drake 1961)

The value of the Drake equation is not in knowing the numerical equivalent of N. Rather, the value is that here we have a template for structuring research and filtering incoming data. As research advances, new numbers can be plugged in. The calculations will change as new information is gathered. As of the present moment, NASA estimates that 1021 planets exist in the universe, of which 1010 might be earthlike (NASA, 2003, p.18). George Coyne, S.J., former director of the Vatican Observatory, estimates that there are 1017 earthlike planets in the universe (Coyne, 2000, p. 180). The mere appeal to such big numbers persuades many astrobiologists that contact optimism is justified.

The sense that discovery of ETIL is imminent has grown conspicuously since 1995, when the first planet was found around a star similar to our sun, 51 Pegasi. As technology increased to measure gravitational effects of suspected planets on their respective stars, so has the number of identified planets. These planets cannot be seen directly, but their gravitational pull can be detected by the wobble they cause on their star. Evidence of perhaps two hundred extra-solar planets is now in. As one might expect, larger planets will likely be discovered first; and those already logged seem to be Jupiter sized objects orbiting quite close to their equivalent to our sun.

Although it is not clear exactly what a planet needs to have in order to generate life or to sustain life that comes first as a visitor, astrobiogists are looking for a planet that is earth size, metal rich, and sufficiently distant from its respective sun in order to provide liquid water. It might need to provide molecular oxygen and ozone, according to NASA’s roadmap. To fit within the biophilic range, such a planet should be like the porridge Goldilocks preferred to eat, not too hot and not too cold. A Goldilocks planet would find itself in a Circumstellar Habitable Zone (CHZ). And such a planet would need to remain stable and safe for a long period of time, perhaps earth years numbered in the billions. To date, no empirical evidence that a Goldilocks planet exists is in; even though speculative considerations make many astrobiologists optimistic.

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Go to Genetics Topic Index

The Speculations of the Contact Optimists

AstroTheology: Religious Reflections on Extraterrestrial Life Forms
Theological Reflections on ETNL
Contact Optimists vs. Unique Earthers
The Place of Evolution in the ETI Myth
How a Theologian Interprets Myth
The Astrobiological Delusion Regarding the Future of Religion


Ted Peters
Dr. Ted Peters

See also:

Will ET End Religion?
Are We Alone?
Evangelical Atheism Today: A Response to Richard Dawkins
Theistic Evolution: A Christian alternative to atheism, creationism and intelligent design
Does God Exist?
The Relation of Science & Religion