Those of us who saw the late Cornell astronomer Carl Sagan on TV remember the glee with which he emphasized that the universe contains stars numbering “billions and billions.” If only a small percentage host habitable planets like Earth, Sagan proclaimed, life must exist elsewhere. Now, more refined numbers are coming in.

In Tuesday’s San Francisco Chronicle, science writer David Perlman (yes, sometimes people think I’m him) reported on calculations by a team of planet hunters from UC Berkeley. It seems that our Milky Way Galaxy contains 50 billion stars resembling our sun. These stars serve as hubs for 11 billion planets the size of Earth. Each orbits its sun at a distance yielding temperatures mild enough to enable the existence of water—and thus life.

I did my own math. Unfortunately, my calculator couldn’t display a number as high as 11 billion (11 plus nine zeroes). So I wrote the number down and struck through two zeroes. Bingo! If biochemical processes work out on just one percent of those planets, 110 million of them harbor life.

But let’s say biochemistry works out on only one-tenth of one percent of those 11 billion planets. We’re down to “only” 11 million planets. That’s a bunch. Moreover, this is just in our local galaxy. Estimates of the total number of galaxies range from 100 million to 500 million. Odds seem reasonable that life exists elsewhere. And if just one percent of planets with life host intelligent life…

Can we find that intelligent life? In 1985, Lily Tomlin starred in a one-woman Broadway show, “The Search for Signs of Intelligent Life in the Universe” by Jane Wagner. It later came out on film. The show left audiences laughing. It also left them continuing to search since they to exit the theater for the everyday world.

Indeed, it can be tricky to locate intelligent life right here on Earth. Mark Twain wrote, “Man is the only animal that blushes. Or needs to.”

Human nature is perplexing. We boast impressive knowledge of the workings of the universe. We also indulge in immense cruelty and folly. Where does humanity stand in the greater scheme of things? The 18th-century Chassidic rabbi Simcha Bunem understood our dual nature. He taught: Every person should have two pockets. In one should be a note stating, “For my sake the world was created.” In the second, a note should advise, “I am but dust and ashes.”

Cognitive dissonance led me to write a short story, “Beautiful!” A former astronaut feels great unease on his 80th birthday. He can’t help considering the overwhelming awe he experienced in space and the plight of a homeless man in his suburban neighborhood.

I could list humanity’s greatest accomplishments and failures, but you know them. What none of us knows is whether intelligent life actually exists out there and in what form. This arouses in me a measure of fear. Not that, as in much science fiction, intelligent life on another planet may be different from us. But that it may be much the same.

Responding is simple. Click on “comments” above then go to the bottom of the article.

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  1. Carolyn Perlstein on November 9, 2013 at 3:53 am

    I guess we’d all like to think that our outer space counterparts have somehow eclipsed human frailty.

  2. RWE on November 9, 2013 at 6:13 am

    The blog brings to mind the Fermi Paradox, Drake Equation, SETI, etc. ( If they’re out there, where are they? RWE

    • David on November 9, 2013 at 3:58 pm

      Ah, that’s the question. Then again, where are we? Okay, that’s a trick question. “Ayecha?” — “Where are you?” God asks Adam and Eve after they’ve eaten the forbidden fruit, discovered their nakedness and hidden in the garden. This may also be translated as “What’s up with you?” So what’s up with us? If we’re the only intelligent life there is, why don’t we take a more intelligent approach to each other? Or, if we can’t find signs of other life out there, does that mean it doesn’t/can’t exist? As to the Fermi Paradox, didn’t Al Fermi play second base for the Chicago White Sox and the Chicago Cubs on the same day during World War Two?

  3. Tracy on November 9, 2013 at 4:59 pm

    Well, we know one place intelligent life does NOT exist — among dodger fans. But, it is nice to have an explanation for that telescope in your backyard, Mr. Perlman.

  4. Tom on January 26, 2014 at 9:06 am

    Carl Sagan NEVER said billions and billions in his series Cosmos. And the Milky Way has about 300 billion stars, not 50 billion. The Milky Way is a barred spiral galaxy some 100,000–120,000 light-years in diameter which contains 100–400 billion stars. It may contain at least as many planets as well. The Solar System is located within the disk, about 27,000 light-years away from the Galactic Center, on the inner edge of a spiral-shaped concentration of gas and dust called the Orion–Cygnus Arm. The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source named Sagittarius A* which is likely to be a supermassive black hole.
    From Wikipedia, the free encyclopedia

    • David on January 26, 2014 at 4:37 pm

      I trust that Wikipedia has it right. Either way, we have a lot to learn.

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