FERMI’S PARADOX

May 30, 2015


The sources for this post are as follows: 1.) waitbutwhy.com, 2.) SETI Institute, and 3.) Wikipedia.

“Some people stick with the traditional, feeling struck by the epic beauty or blown away by the scale of the universe.  Personally, I go for the old existential meltdown followed by acting next half hour. But everyone feels something”.  Physicist Enrico Fermi felt something too and asked—“Where is everybody?”

QUESTION:  Our Galaxy Should Be Teeming With Civilizations, But Where Are They?

The remark came while Fermi was discussing with his mealtime mates the possibility that many sophisticated societies populate the Galaxy.  In 1950, while working at Los Alamos National Laboratory, Fermi had a casual conversation while walking to lunch with colleagues Emil KonopinskiEdward Teller and Herbert York.    The men discussed recent sightings of UFOs and an Alan Dunn cartoon facetiously blaming the disappearance of municipal trashcans on marauding aliens. They then had a more serious discussion regarding the chances of humans observing faster-than-light travel by some material object within the next ten years. Teller thinks Fermi directed the question at him, asking “Edward, what do you think? How probable is it that within the next ten years we shall have clear evidence of a material object moving faster than light?” Teller answered one in a million. Teller remembers Fermi said, “This is much too low. The probability is more like ten percent” [the probability of a ‘Fermi miracle’]. Konopinski did not remember the exact numbers “except that they changed rapidly as Teller and Fermi bounced arguments off each other.”  They thought it reasonable to assume that we have a lot of cosmic company. But somewhere between one sentence and the next, Fermi’s supple brain realized that if this was true, it implied something profound. If there are really a lot of alien societies, then some of them might have spread out.

A really starry sky seems vast—but all we’re looking at is our very local neighborhood. On the very best nights, we can see up to about 2,500 stars or roughly one hundred-millionth of the stars in our galaxy. Almost all of them are less than 1,000 light years away from us (or 1% of the diameter of the Milky Way).  It is very hard to imagine the magnitude of this very fact but our universe is IMMENSE. So what we’re really looking at is this:

Milky Way Galaxy

Let us take a look at just how grandiose our universe is.

  • As many stars as there are in our galaxy (100 – 400 billion), there are roughly an equal number of galaxies in the observable universe so, for every star in the colossal Milky Way, there is a whole galaxy out there. All together, that equates to a range of between 1022 and 1024 total stars.   This means that for every grain of sand on every beach on Earth, there are 10,000 stars out there.  Numbers very hard for anyone to deal with.
  • There is not total agreement concerning what percentage of those stars are “sun-like” (similar in size, temperature, and luminosity).  Opinions typically range from five (5%) to twenty (20%). Going with the most conservative side of that five percent (5%), and the lower end for the number of total stars (1022), gives us 500 quintillion, or 500 billion billion sun-like stars.
  • There’s also a debate over what percentage of those sun-like stars might be orbited by an Earth-like planet (one with similar temperature conditions that could have liquid water and potentially support life similar to that on Earth). Some say it’s as high as fifty percent (50%) but let’s go with the more conservative twenty-two percent (22%) that came out of a recent PNAS study. That suggests that there’s a potentially-habitable Earth-like planet orbiting at least one percent (1%) of the total stars in the universe—a total of 100 billion billion Earth-like planets.  So there are 100 Earth-like planets for every grain of sand in the world. Think about that next time you’re on the beach.
  • Moving forward, we have no choice but to get completely speculative. Let’s imagine that after billions of years in existence, one percent (1%) of Earth-like planets develop life.  If that’s true, every grain of sand would represent one planet with life on it.  Imagine that on one percent (1%) of those planets, the life advances to an intelligent level like it did here on Earth. That would mean there were 10 quadrillion or 10 million billion intelligent civilizations in the observable universe.
  • Just for our galaxy, and doing the same math on the lowest estimate for stars in the Milky Way (100 billion), we’d estimate that there are 1 billion Earth-like planets and 100,000 intelligent civilizations in our galaxy.
  •  Our sun is relatively young in the lifespan of the universe. There are far older stars with far older Earth-like planets, which should in theory mean civilizations far more advanced than our own. As an example, let’s compare our 4.54 billion-year-old Earth to a hypothetical 8 billion-year-old Planet X.

(I told you this was big.)  The technology and knowledge of a civilization only 1,000 years ahead of us could be as shocking to us as our world would be to a medieval person. A civilization 1 million years ahead of us might be as incomprehensible to us as human culture is to chimpanzees. And Planet X is 3.4 billion years ahead of us.  You, of course, can see where we are going here.

If Planet X has a similar story to Earth, let’s look at where their civilization would be today (using the orange time-span as a reference to show how huge the green time-span is):

TIME-SPAN

Scientific endeavor has categorized three distinct possibilities relative to possible civilizations. These are as follows:

  • Type I Civilization has the ability to use all of the energy on their planet. We’re not quite a Type I Civilization, but we’re close (Carl Sagan created a formula for this scale which puts us at a Type 0.7 Civilization).
  • Type II Civilization can harness all of the energy of their host star. Our feeble Type I brains can hardly imagine how someone would do this.
  • AType III Civilization blows the other two away, accessing powers comparable to that of the entire Milky Way galaxy.  If this level of advancement sounds hard to believe, remember Planet X above and their 3.4 billion years of further development. If a civilization on Planet X was similar to ours and was able to survive all the way to Type III level, the natural thought is that they’d probably have mastered inter-stellar travel by now, possibly even colonizing the entire galaxy.

There is no answer to Fermi’s Paradox.  But there may be several theories.

  • Explanation Group 1: There are no signs of higher (Type II and III) civilizations because there are no higher civilizations in existence.  We are Rare!
  • We are the very FIRST intelligent civilization in our universe.  (This sounds somewhat impossible given the age of the universe.)
  • Type II and III intelligent civilizations are out there and there are logical reasons why we might not have heard from them.
    • Super-intelligent life could very well have already visited Earth, but before we were here.
    • The galaxy has been colonized, but we just live in some desolate rural area of the galaxy.
    • The entire concept of physical colonization is a hilariously backward concept to a more advanced species.
    • There are scary predator civilizations out there, and most intelligent life knows better than to broadcast any outgoing signals and advertise their location.
    • There’s only one instance of higher-intelligent life—a “super-predator” civilization (like humans are here on Earth)—who is far more advanced than everyone else and keeps it that way by exterminating any intelligent civilization once they get past a certain level.
    • There’s plenty of activity and noise out there, but our technology is too primitive and we’re listening for the wrong things. (I personally like this theory.)
    • We are receiving contact from other intelligent life, but the government is hiding it. (Our government is so big and so inept they could not keep this secret.)
    • Higher civilizations are aware of us and observing us (AKA the “Zoo Hypothesis”).
    • Higher civilizations are here, all around us. But we’re too primitive to perceive them.
    • We’re completely wrong about our reality.

I truly think this is fascinating and I do believe there is life in the universe.  Intelligent life—we can only hope.

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