Intelligent Life in the Universe

Infantile Giganticus Among Other Species

The thought of civilizations far away (or perhaps nearby) making contact with humans has captivated humans for most of history, and is even a constant component in our vast entertainment industries today. Apart from religions, which have commonly described Gods as cosmic beings for thousands of years, the first documented mention of alien life forms came in the 2nd century in the form of a satire called "True History" by Lucian.  Since then we have seen aliens referenced consistently throughout history; from 10th century Japanese tales, to 17th century Baroque literature, into modern media with War of the Worlds (1940), Star Trek (1966), E.T. (1982), and The Avengers (2012).

Hollywood isn't the only one pondering aliens.  Science has also taken a fascination with extraterrestrial life and have quietly offered some interesting thoughts as to what might be lurking in the Universe.  I'll discuss some of the more thought-provoking concepts below, including the Fermi Paradox, Drake Equation, SETI, and more.

To begin we'll start with the assumption that because the Universe is so large, there must be intelligent life out there, right?  The Fermi Paradox came from scientists wondering that if this were true, why haven't we met these life forms?  It states four key assumptions:

1. Our Sun is 4.6 billion years old, the Universe is 13.8 billion years old, and there are billions of stars like our sun that are much older.
2. Some of these stars have habitable zones that produce planets similar to Earth, where life can evolve into intelligent life over billions of years.
3. Some of these civilizations would be capable of interstellar travel if we're already considering such technology (like the Alcubierre Drive).
4. In a time scale of billions of years, galaxies should be colonized within a few million years of interstellar travel becoming possible.

Even conservative calculations predict the proper heavy elements were around and conditions were stable enough for habitable planets to start forming roughly 12 billion years ago.  At nearly 8 billion years older than Earth itself, these ancient planets have had more than enough time for millions of advanced civilizations to have been born and passed on already.  Going back to the Fermi Paradox, if we assume those 4 points are valid, Earth should have been colonized or at least visited, yet we've never observed evidence of other civilizations.  From this starting points there are many great arguments as to why we haven't made contact.  

The Drake Equation is a famous formula meant to estimate the number of technological civilizations in the Universe, and equals (and skip this if you don't care, seriously):

R (rate of star formation) * Fp (fraction having planets) *  Ne (average # of life supporting planets per star that has planets) * Fl (planets that could support life / planets that would develop life) * Fi (fraction that would then develop intelligent life) * Fc (fraction that would have technology we could observe signs of) * L (length of time those signals would be released into space)

The Picture Summary For Those That Don't Care, Seriously

Each element of the equation is based in some field of science, but still are reliant on variables that depend on who is inputting the calculations, and can result in widely varied estimates of the number of advanced civilizations.  The wide results range from 2 intelligent civilizations to 280,000,000. 280,000,000 is a huge number but the fact that the low is still greater than 1 should be the more important observation.

Deferring to the great thinkers on this subject, Steven Hawking proposed 4 possibilities as to why we had not observed the intelligent life that should be out there.  

1. The first possibility is that perhaps life is such an extremely rare occurrence that there are only 2 or 3 civilizations separated by the vastness of the Universe.  With only one species of intelligent life to observe, our sample size is too small to know how likely life is to form, although most scientists agree it should form fairly easily in the vastness of space and time.  
2. The second possibility is that evolution of intelligence is not necessarily beneficial to survival, and so intelligence evolves from such random mutations that there may be life everywhere in the Universe but it doesn't evolve past the intelligence of most alpha predators on Earth (just enough to live comfortably on instincts).  Part of the support for this proposal is that it took around 2.5 billion years on Earth to evolve from single cell to multicell organisms, from there life required more resources to grow into bigger animals.  Large meteor strikes would wipe out any organism bigger than small mammals, which scientists predict might occur around once every 20 million years.  It's been 70 million years since the last such strike, which is an abnormal amount of time, and fortunately enough for intelligent life to come around.  
3. The third possibility Hawking presented was that when civilization enters the external transmission phase (develops written language) life eventually destroys itself (nuclear war, global neglect, artificial intelligence, etc).  Hopefully this isn't the case for humanities sake.
4. The fourth possibility is that we have simply overlooked signs of intelligent life so far, and that is exactly why Hawking is a firm backer of SETI.

SETI, or Search for Extraterrestrial Intelligence, was initially a United States government project until private funding took over in 1995.  SETI itself is a collection of entities, led by Harvard and University of Cal, Berkeley, that looks for signs of intelligent life (non naturally forming occurrances) such as electromagnetic radiation and gamma-ray bursts, and continues to search today. 

Waiting For The Next Columbus

There is another possibility that many are probably wondering about, which is that intelligence life has traveled past Earth, or maybe even stopped off to visit.  One line of thinking revolves around the assumption that intelligent life knows about mankind and chooses to remain secret.  They might choose to remain secret in order to study us.  Or, they might simply not care.  If they're vastly technologically superior the common metaphor is that a human wouldn't stop to interact with an anthill in the same way an extremely advanced species wouldn't stop to interact with a species that hasn't even colonized its neighboring planets.  Additionally, if a person dropped a candy wrapper next to the anthill the ants wouldn't know that the wrapper isn't naturally occurring and instead comes from an advanced species, so perhaps we've overlooked their presence.  If that sounds outrageous, consider: Basic tribes were all that existed on Earth 8,000 years ago, and considering where we are today, how might a human in 40,000 years look at us today? What about 40 million or the 8 billion years planets might have existed with intelligent life before us?

If we don't want to wait patiently to be discovered we will need to travel and colonize the planets. Luckily we have about 5 billion years before our sun explodes, at which point our solar system should be a distant memory.  Of course in 15 billion years the rest of the stars will die out according to the Second Law of Thermodynamics, but there's no reason we can currently foresee us not living on forever. In the near term we need our species to find a way to live when Earth is depleted, as it will be one day (go see Interstellar).  Luckily we're intelligent life and that means be adapt.  According to Hawking we've entered a new stage of self designed evolution where we'll evolve, through technology, at an exponential rate until one day we're cruising the cosmos with the other civilizations.

-Ryan Gardner