Wednesday, December 18, 2013

EIGHT POINT EIGHT BILLION

For years astronomers have speculated about the abundance of other intelligent life in the universe.  Recently a study was published in the Proceedings of the National Academy of Sciences reporting that an estimated 8.8 billion stars in the Milky Way galaxy have earth-like planets orbiting in their “habitable zone,” where the star’s energy would permit the existence of liquid water at the planet’s surface.  The researchers made this conclusion based on a survey of some 42,000 sun-like stars in our local region of the Milky Way galaxy.  Only a few years ago the existence of so-called exoplanets--planets orbiting stars other than our sun--was still just theoretical.  Now astronomers are routinely discovering exoplanets, and their numbers are already in the hundreds.  Hence this study.


We’re talking massive numbers here.  While 8.8 billion is a huge number, it’s dwarfed by other astronomical numbers.  For example, there are an estimated 200 billion stars in the Milky Way Galaxy.  And, if you’re still not impressed, there are some 100 billion galaxies in the observable universe.  

[As an aside, and to provide a little perspective here, it turns out that there are more stars in the observable universe than there are grains of sand on all of the beaches and all of the deserts on earth, combined. Lots more, actually.]  

So, assuming the Milky Way is a typical galaxy, that would make an estimated 8.8 times 10 to the 20th planets in their stars’ habitable zones.  To state it another way, that’s 880,000,000,000,000,000,000 planets that might harbor life as we know it.  Not all of those planets would have life, of course.  But if one assumes that intelligent life is a one in a billion possibility, that would still leave nearly one trillion (that’s with a “T”) planets with intelligent life.  And, since intelligent life here is of such recent origin, relatively speaking, chances are that most of the other intelligent races are way ahead of us.  Awe-inspiring . . . and humbling.  Now how special do you feel?

And my point?  Well, I’m asking how this fact relates to the religious--I suppose mostly fundamentalist Christian--belief that the human race is somehow special, the belief that the universe was created just for us or the belief that we represented a unique “testing ground” for God’s experiment.  But what about all of those other 880 billion intelligent races?  Are they all just watching us?  Isn’t that just a bit arrogant?  

Isn’t it more reasonable to believe that we originally thought we were special only because we didn’t understand the size and nature of the universe?


© 2013 John M. Phillips

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