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Brice Hansen
Professor Maenhardt
ENGH 1010
April 15, 2012
Life Beyond Earth
Since the dawn of time mankind has looked to the sky and wondered “Are we alone in
the universe?” This question is not just one of cosmic significance but has the very real
potential of revealing to us our galactic destiny. Though the question invites answers that are
both philosophical and theological, the scientific answer is drawing ever closer as technology
advances and as we gain a better understanding of the universe and of ourselves.
The search for intelligent life consists of pointing large radio telescopes at distant stars
and listening for radio waves in the form of manufactured patterns, and was pioneered in part
by Frank Drake. In 1960 Drake started Project Ozma by pointing a radio telescope at two of the
nearest stars, Tau Ceti and Epsilon Eridani, only to find nothing but false hope when a military
plane flew nearby giving a false positive to his equipment (Squeri). The rumors of his success
quickly spread and the interest in his work was cemented in the public opinion. Drake would go
on to form the Search for Extraterrestrial Intelligence program also known as SETI but not
before further validating such searches by proposing his famous Drake Equation at a
conference in Green Bank West Virginia.
The Drake Equation is a means by which to estimate the potential number of intelligent
civilizations that might exist in this galaxy. It is expressed as N = R* × fp × ne × fl × fi × fc × L where
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N is the expectant number of civilizations and the other terms are defined as follows: R* is the
average rate at which stars are formed in this galaxy that could support life. fp is the fraction of
those stars that actually have planets. ne is the number of those planets that could bear life. fl is
the fraction of life capable planets where life actually occurs. f i is the fraction of those planets
where intelligent life evolves. fc is the fraction of that intelligent life that forms a
communicating civilization, and L is the average lifespan of such a civilization (Nadis). It’s readily
acknowledged that the Drake Equation is merely an estimate and its largest contribution is to
help narrow down the search into these seven variables.
With generous numbers used in the Drake Equation it could be estimated that over
100,000 civilizations exist in this galaxy, while on the contrary, more conservative numbers
could make that estimate fewer than one. Proponents of either estimate hotly debate the
values that should be placed in the poorly understood variables of the Drake Equation. As
science and technology advance, we are getting closer to understanding some of these
variables and in turn we are getting closer to a more accurate view of the universe.
We are able to calculate the average rate at which suitable stars form with a large
degree of accuracy. Suitable stars are those that are just the right size and condition to have a
habitable zone that could exist in relative unchanging conditions long enough for intelligent life
to evolve; this is estimated to be 4 to 19 suitable stars born in this galaxy each year (Nadis).
Current searches are revealing extrasolar planets at an increasing rate. Presently over 1000
planets have been discovered outside of the solar system and 1000 more are being watched.
Even though the process of finding extrasolar planets is in its infancy we are finding many that
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exist in various conditions that could hinder their ability to support life. For example, only 2.2%
of the planets with known orbits maintain that orbit in a range similar to that of Earth; if that
orbit, which is crucial to a planet’s temperature, varies too much life might not survive long
enough to evolve the proper adaptations (Smith).
We are looking to the stars to determine if our planet is unique, but we must also look
at our planet to determine if life is unique. It is estimated that Earth is 4.65 billion years old and
the earliest signs of life appear to have originated around 3.85 billion years ago (Longstaff). This
means that life might have started on Earth 800 million years after it was formed; a relatively
short time by universal standards, giving credence to Drake’s personal perspective. Drake felt
that almost all habitable planets will evolve life at some point and that almost all life will
eventually evolve into intelligence (Nadis). This is perhaps the most disagreed on aspect of the
Drake Equation by those that feel there is intelligent life elsewhere in the universe and those
who do not. The fact that the conditions of the origins of life have never been perfectly
duplicated by modern science seems to indicate that other conditions could be a factor. It’s
estimated that 15 mass extinction events occurred on Earth before humanity came about in its
present state, possibly even contributing to the conditions for us to evolve. Imagine the
likelihood of humans developing into the dominant species on Earth if dinosaurs were still alive
(Smith).
Before Frank Drake ever put a number to the vast potential of the universe Enrico Fermi
acknowledged that given the size and age of the universe we should have already found some
evidence of intelligent life. This discrepancy became later known as the Fermi Paradox and is
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often the grounds of many people who wonder “What does it matter?” Some feel that
intelligent life exists in this universe and some do not, while others feel that it’s not worth
debating because there is no way we could ever know. Even if life was common place, the
distance between habitable planets is extremely vast and arguably untraversable. Signals
traveling at the speed of light could still take hundreds of years to reach the closest civilizations,
a figure that has significant meaning when you realize that humanity only started using radio
waves for communication about 100 years ago (Shostak). Another possible scenario for the
Fermi Paradox is that all intelligent civilizations don’t last long enough to leave a significant
galactic fingerprint. Assuming that we can use human history as a model for what to expect
elsewhere in the universe, other civilizations would also have to face issues of depleting
resources, infighting, and potential self-annihilation. If extraterrestrial civilizations are all
relatively short lived then the last variable of the Drake Equation would be severely limiting,
even with generous estimates of the other variable only thousands of civilizations would be
possible in a galaxy of billions of stars (Shostak).
So what does it all mean? The lessons of our future will become clear as we learn more
about our past. The progress we make in discovering the origins of life will give us great insight
as to the nature of the universe and the uniqueness of life; is life a mystery confined only to this
little point in space or is it as abundant as the stars? Is our intelligence the result of an
unrepeatable coincidence or an inevitable result of evolution? The true benefit of this line of
inquire is knowing our place in the universe; if we find our galactic neighbor then maybe we can
learn from them how to preserve our resources and possibly spread our species to other
planets, but if we are special then it’s our responsibly to learn on our own how to preserve life
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and our resources, and we can invest our efforts in that significant cause. Is the silence of the
skies telling us that societies just don’t last? Are we destined to follow in the footstep of other
extraterrestrial civilizations or can we overcome our obstacles and preserve our race for
millennia? As humanity searches for life in this universe we discover more about ourselves and
our future. To quote Frank Drake’s two most influential colleagues, Philip Morrison and
Giuseppe Cocconi, "The probability of success is difficult to estimate, but if we never search, the
chance of success is zero" (Squeri).
Works Cited
Longstaff, Alan. "Quest for a Living Universe." Astronomy Vol. 33, No. 4. April 2005: 28-34. SIRS
Issues Researcher. Web. 05 Apr 2012.
Nadis, Steve. "How Many Civilizations Lurk In The Cosmos? (Cover Story)." Astronomy 38.4
(2010): 24. MasterFILE Premier. Web. 6 Apr. 2012.
Shostak, Seth. "Galactic Empires???." Odyssey 6.5 (1997): 38. MasterFILE Premier. Web. 6 Apr.
2012.
Smith, Howard A. "Alone In The Universe." American Scientist 99.4 (2011): 320. MasterFILE
Premier. Web. 6 Apr. 2012.
Squeri, Lawrence. "When ET Calls: SETI Is Ready." Journal of Popular Culture. Feb. 2004: 478+.
SIRS Issues Researcher. Web. 05 Apr 2012.