In his 1979 book, Extraterrestrial Civilizations, Dr. Asimov takes on the question of whether we are alone in the galaxy, and he takes a fairly straightforward and conservative (in his estimation) approach to determining an estimate of how many technological civilizations there are in our Galaxy alone.

He comes up with the number 390 million, and further extrapolates that most of them would be more advanced than we are. He makes a lot of assumptions, for example, he assumes (optimistically, he admits) that our civilization will continue to last on Earth as long as Earth is able to support life, which he suggests is about 7.4 billion more years, and then that this is the average duration of a civilization. (Therefore, only 1/1,500,000 of the civilizations in the galaxy are at or below our level of sophistication and advancement.)

It’s fascinating to “watch” Dr. Asimov manipulate the science to come up with the numbers he comes up with, starting with the total number of stars in the galaxy, which he estimates at 300 billion, and whittling it down based on estimates based on the best scientific data available to him at the time. By the end, you are almost awed by the potential number of civilizations – not just life bearing planets, but ones that develop an advanced civilization.

So then, he goes on to ask, why haven’t we found any evidence of them? He talks about the physics limiting the reality of interstellar travel, the energy expenditures, the times involved, and the difficulties of finding likely targets for exploration. He talks about the difficulties in detecting the various potential signals that an advanced civilization might send out, and whether we are too ‘primitive’ to detect such signals, or whether said signals are just not at high enough energy to be detected by our efforts to do so to date. (Remember, this was written in 1979.)

In the end, Dr. Asimov suggests that the efforts themselves to expand beyond our world and to detect extraterrestrial civilizations will lead to profit and to helping ourselves. “Let us strive to inherit the Universe that is waiting for us; doing so alone, if we must, or in company with others – if they are there.”

This is an older book, and one that doesn’t have the benefit of the latest (this century’s) knowledge about planets and star systems and an even longer history of SETI and probes and the Hubble Telescope.  But it’s one that expresses an optimism that I think we need in our society today.  It challenges its readers to look to that next horizon, to the “final frontier,” in order to maintain that human spirit through accepting a challenge.

We have so many problems here in the United States, and in the world, that at this point in history (2016), any sort of effort like this might be impossible, at least politically. But perhaps having a goal to inspire us and to influence us would be a good thing, and help us to surmount some of these issues that seem so important.

(I wrote this in 2008 and just made a few changes prior to publication here…)



  1. Steven M. Moore

    Hi Scott,
    Asimov’s analysis and book seem a wee bit contradictory. He excluded ETs from most of his sci-fi. The Foundation trilogy and extended Foundation series (where he brought the robot and Foundation universes together) have none, and the reason is “explained” in his time travel novel. That’s one way to avoid the criticism that a human sci-fi author can’t really get into an ET’s mind.
    Asimov’s arguments revisit the Fermi paradox (where are they?) with the Drake equation. In a recent post, I described a journal article that discussed the terms in that equation and how all those extra-solar planets can be used to calculate the likelihood that no one is “out there,” i.e. we’re alone.

  2. Scott Dyson Post author

    I thought that the lack of ETs in the original Foundation Trilogy had something to do with John Campbell’s preferences. He does make references to THE END OF ETERNITY in later Foundation novels as the reason that humans are alone in the Galaxy.

    I also thought that he did an excellent job with the aliens in THE GODS THEMSELVES.

    I may have missed that recent post. I’ll have to go back and see what I missed! Thanks for the comment, again!

  3. Steven M. Moore

    Hi Scott,
    The post is “Where are they?” from June 21.
    I think I read about Asimov’s use of the Eternals to make the Universe safe for humans in an Asimov interview too. I didn’t know anything about Campbell’s meddling. “The Gods Themselves” was a very early short story or novel, I believe. Frankly, I don’t remember it very well.
    As a young’un, I devoured sci-fi. I discovered mysteries and adventures a wee bit later, but devoured them too. Couldn’t stand most of the books I read in HS English. Those assignments seemed designed to convince students who don’t think they like to read that they really don’t like to read.
    Take care.

  4. Scott Dyson Post author

    I love the comment about proving to kids that they don’t like to read. (Though my son’s found something to appreciate about most of the books he’s read for his HS English classes.)

    I don’t know where THE GODS THEMSELVES falls in the Asimov chronology, but I remember reading that he said it was a response to those who said he couldn’t write aliens. It was a three-part novel, if I remember…each section had as its subtitle part of a quote that went something like “Against stupidity, the Gods themselves contend in vain.” (I’m not sure “stupidity” was the word in the quote.) It was about an exchange of matter with beings that inhabited a different universe that had different physical laws, so that the material received from the alien universe provided an uninterrupted source of energy for Earth. The aliens were willing to sacrifice our universe in order to be able to access the energy coming from it. Right now they needed some sort of portal, but if they were able to explode our universe or something like that, they’d be able to access the energy directly from their end. The alien story centered on three young aliens who are trying to stop their adults from doing what they’re planning. But it turns out that when the three young aliens have alien sex, they BECOME the lead alien who is directing the project. They have to do a final meld, or whatever, and they think that they’ll become a being that is capable of stopping things, but instead they become who they already are when they mate. Interesting alien sex ideas and interesting premises all around, I thought. I remember it fairly well, though I haven’t read it in years.

    You might wanna give it a reread if you can find it.

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