Carl Sagan Remembered

by Paul Gilster on December 20, 2006

When I think about Carl Sagan, the tenth anniversary of whose death we remember today, the first thing that comes to mind is a quote about the wonders of relativistic interstellar flight. It’s worth quoting at length:

If for some reason we were to desire a two-way communication with the inhabitants of some nearby galaxy, we might try the transmission of electromagnetic signals, or perhaps even the launching of an automatic probe vehicle. With either method, the elapsed transit time to the galaxy would be several millions of years at least. By that time in our future, there may be no civilization left on Earth to continue the dialogue. But if relativistic interstellar spaceflight were used for such a mission, the crew would arrive at the galaxy in question after about 30 years in transit, able not only to sing the songs of distant Earth, but to provide an opportunity for cosmic discourse with inhabitants of a certainly unique and possibly vanished civilization. Despite the dangers of the passage and the length of the voyage, I have no doubt that qualified crew for such missions could be mustered. Shorter, round-trip journeys to destinations within our Galaxy might prove even more attractive. Not only would the crews voyage to a distant world, but they would return in the distant future of their own world, an adventure and a challenge certainly difficult to duplicate.

That’s from Intelligent Life in the Universe, which Sagan and Iosef Shklovskii published in 1966 (Holden-Day, pp. 443-444). It’s actually a translation and extended revision of Shklovskii’s older Universe, Life Mind, and the quote draws on a 1963 Sagan paper called “Direct Contact Among Galactic Civilizations by Relativistic Interstellar Flight” (Planetary and Space Science 11, pp. 485–98). Sagan had sent Shklovskii the paper even before the latter’s book appeared. The result in English became a collaborative effort that drew on the wisdom of two outstanding minds.

I don’t know how many space scientists were fired by this vision of human voyaging not just to another star but another galaxy, but I suspect this book still sits on the shelf of many a researcher. It awoke in me the sense of awe that Poul Anderson would go on to tap in Tau Zero, his fine novel about a runaway starship that makes Sagan’s 30-year voyages to Andromeda seem tame by comparison. But that’s what Sagan did. He could render hard science into celestial mental voyaging.

Good scientists do that in their own minds. Sagan’s genius was the ability to convey it to a broad audience, using prose that was supple and keen as a knife-edge. The great mystery writer Ross Macdonald once said of Raymond Chandler that he wrote ‘like a slumming angel.’ It’s the perfect phrase for Sagan as well, whose voice was distinctive and marked by a preternatural clarity. When Cosmos widened his reach to television, he was able to bring the discoveries of our telescopes and spacecraft into the home and (with a kind of poetry) show us where we stood in the universe.

Pale Blue Dot (1994) was Sagan at his best as he ranged through the Solar System and looked back on a distant Earth. Here’s the memorable conclusion:

The Cosmos extends, for all practical purposes, forever. After a brief sedentary hiatus, we are resuming our ancient nomadic way of life. Our remote descendants, safely arrayed on many worlds through the Solar System and beyond, will be unified by their common heritage, by their regard for their home planet, and by the knowledge that, whatever other life may be, the only humans in all the Universe come from Earth.

They will gaze up and strain to find the pale blue dot in their skies. They will love it no less for its obscurity and fragility. They will marvel at how vulnerable the repository of all our potential once was, how perilous our infancy, how humble our beginnings, how many rivers we had to cross before we found our way.

A slumming angel indeed. Thank you, sir.

Note: As Larry Klaes just pointed out in a comment to this post, Joel Schlosberg is conducting an ongoing Sagan tribute centered on this day, and Larry also notes the Celebrating Sagan weblog in his honor. Larry’s own tribute to Sagan in the Ithaca Times is here. Music of the Spheres has a fine recollection as well. Be sure to read Airminded’s homage, and finally, check Ann Druyan’s thoughts about her late husband.

ljk December 20, 2006 at 10:22

Thank you, Paul, for your excellent tribute to Carl Sagan.

Here are some relevant Web sites about the man on this day
which can all celebrate with and in:

The late Dr. Carl Sagan is being honored in cyberspace starting
on December 20, 2006, the tenth anniversary of his passing.

New York City humanist Joel Schlosberg is organizing a special
memorial “blog-a-thon” among Sagan’s fans throughout the

On his Internet home, Schlosberg suggests that “if you’re a Sagan
fan with a blog, you can participate by posting something related to
him on or near that date. Read or reread a Sagan book and review it;
discuss cool things that you’ve done that’s been influenced by him;
pontificate on one of the many topics he treated (SETI, astronomy,
critical thinking, the history of science, human intelligence….), or post
about something completely surprising.”

To participate in this online celebration and tribute, go to Schlosberg’s
blog site here:

Celebrating Sagan is a not for profit blog working to build a living
memorial to remember the life of Dr. Carl Sagan.

From Italy:

Life Beyond Earth and the Mind of Man

This film is an edited version of a symposium held at Boston University
on November 20, 1972 that explores the implications of the possible
existence of extraterrestrial life within the galaxy and the universe.

The panel members were Dr. Richard Berendzen, astronomy professor
and historian of science at Boston University; Dr. Ashley Montagu,
anthropologist, social biologist and author at Rutgers University; Dr.
Philip Morrison physicist educator and philosopher of science at
Massachusetts Institute of Technology (MIT); Dr. Carl Sagan,
astronomer and exobiologist at Cornell University; Dr. Krister Stendahl, clergyman and theologian at Harvard University; and Dr. George Wald, biologist at Harvard University.

ARC ID: 649452

Edg Duveyoung December 20, 2006 at 11:10

Intelligent Life in the Universe, by Sagan and Iosef Shklovskii was such an eye-opening delight to me. Now, I’m wondering if there exists another such book that may have recently tried to cover that same ground but with all the new information that Sagan and Shklovskii didn’t have at the time of their speculations.

I love for anyone here to point me to a similar but recent attempt.


ljk December 20, 2006 at 11:18

Carl’s third son from his second marriage. Nick is now a successful science
fiction writer who did several episodes of Star Trek: Voyager.

ljk December 20, 2006 at 11:33

Contact with Alien Civilizations

Our Hopes and Fears about Encountering Extraterrestrials

Michaud, Michael A.G.

2007, XIV, 466 p., Hardcover

ISBN-10: 0-387-28598-9
ISBN-13: 978-0-387-28598-6

About this book

This book describes a wide variety of speculations by many authors about the consequences for humanity of coming into contact with extraterrestrial intelligence. The assumptions underlying those speculations are examined, and some conclusions are drawn. The book emphasizes the consequences of contact rather than the search, and takes account of popular views. As necessary background, the book also includes brief summaries of the history of thinking about extraterrestrial intelligence, searches for life and for signals, contrasting paradigms of how contact might take place, and the paradox that those paradigms allegedly create.

Written for:

Readers interested in extraterrestrial life, extraterrestrial intelligence, astronomy, and space exploration. Though the book is written in non-technical language and does not require a scientific background, it will be of interest to researchers, university teachers, and university students.

Administrator December 20, 2006 at 13:08

Edg, that’s just an outstanding question. I’m hoping readers can supply us with a number of interesting titles.

Bruce Irving December 20, 2006 at 14:50

Very nice tribute, Paul. I recalled my first reading of “Intelligent Life” in my Sagan post today – that book was indeed eye opening (and I needed the eye opening help since I was working the graveyard shift in a psych hospital while finishing my physics degree). Unrelated but mentioned a few days before (triggered by Damn Interesting and your Daedalus post), but I finally ordered a copy of “Centauri Dreams.”

Keep up the good work and happy holidays!

george scaglione December 20, 2006 at 15:10

all of this constitutes a wonderful tribute to the late dr sagan.last christmas i was given the series cosmos on dvd – thus far i have seen all of it about 25 times !! my favorite episodes at least 5 times more than that!! he was a great man indeed. respectfully george

Administrator December 20, 2006 at 15:30

And well done with your post as well, Bruce:

Thanks for your nice comments!

ljk January 29, 2007 at 23:47

Searching the Heavens

The late Carl Sagan on questions of science and faith.

Reviewed by Wray Herbert

Sunday, January 28, 2007; BW05


A Personal View of the Search for God

By Carl Sagan

Edited by Ann Druyan

Penguin Press. 284 pp. $27.95

In 1877, the Italian astronomer Giovanni Schiaparelli was looking at Mars through his new telescope, and he noticed intricate etchings in the equatorial region of the planet’s surface. Schiaparelli called these lines canali, by which he probably meant something like “gullies” or “grooves,” but his coinage got wrongly translated into English as “canals.” It was a regrettable linguistic slip.

The idea of Martian canals grabbed the imagination of American astronomer Percival Lowell, scion of the famous Boston Lowell clan, who spun out an elaborate story of a Martian civilization with a central planetary government and the technological wizardry to engineer a massive system of aqueducts. Lowell even used his own Arizona observatory to identify the Martian capital, called Solis Lacus.

There are no canals on Mars. No cities either, and no government. Indeed, no signs of past life whatsoever, as we know today. All of this was an elaborate phantasm of Lowell’s fertile mind, yet as late as the 1950s, popular culture was saturated with imagery of Martians as a technologically advanced extraterrestrial race.

The late Carl Sagan used the misbegotten tale of Martian engineers, in his 1985 Gifford Lectures in Natural Theology at the University of Glasgow, as a cautionary tale about the power of belief and yearning to trump science and reason. The Cornell University astrophysicist, Pulitzer Prize-winning author and TV personality was alarmed by the persistence of such magical thinking even into the late 20th century, despite tremendous scientific progress in understanding both human nature and the cosmos. He used the prestigious lecture series (collected here for the first time by his widow and long-time collaborator, Ann Druyan) as an opportunity to challenge the evidence for everything from the Bermuda Triangle to UFOs to angels and deities. But just as important, he used the lectures to spell out his views on the common ground shared by science and spirituality.

Sagan does not deny the existence of God. Nor does he affirm it. As he quips in the lively Q&A section appended to the lectures, “Absence of evidence is not evidence of absence.” What Sagan does do is insist on the primacy of scientific method and scientific evidence, and he holds the many and various “proofs” of God’s existence up to these scientific standards. Most are found wanting. But Sagan is not harsh in his critiques of religious thought; he is more perplexed by theology’s narrow and unimaginative vision.

Why would an all-powerful God work only on a local (and recent) project like the Earth when there is a vast, 15-billion-year-old universe out there, with countless galaxies containing countless stars and the possibility of countless worlds? Why didn’t God let us know about quantum mechanics and natural selection and cosmology from the get-go? And why would theologians insist on such a provincial version of the creation and God’s imagination?

Sagan is not being flip or heretical, though he is intellectually playful and obviously likes the fray. Sagan took his own spirituality seriously — indeed, he defined science as “informed worship.” The closest he comes to articulating his own view of God is to describe admiringly the philosophies of Spinoza and Einstein, who basically considered God the sum total of all the laws of physics. These laws, he emphasizes again and again, govern not just the Earth and humanity but every solar system and every star and every galaxy. They are not local ordinances.

Central to Sagan’s personal search for the existence of God is the question of other life in the universe. For him, the requirements for proof of extraterrestrial intelligence are essentially the same requirements for proof of angels or demigods or a God. Sagan spends much of one lecture on the so-called Drake equation, which is a way of estimating the number of technologically advanced civilizations in the galaxy. The equation incorporates several values, including the rate of star formation, the fraction of stars with planets around them, the fraction likely to have evolved intelligent life and so forth.

The confounding value is L, which stands for the average lifetime of a technologically advanced civilization. If you plug in an optimistic value, assuming such civilizations are long-lived, then the equation predicts that there are millions of intelligent societies out there, and likely one just a few hundred light years away. That’s a long way by spaceship, but really right next door if you’re going at the speed of light, which means that our radio telescopes should be able to pick up signals from other advanced beings who want to contact us.

But what if the value of L is low? What if technologically advanced civilizations don’t last very long on average? If highly intelligent races tend to perish quickly, then the Drake equation predicts not millions of such civilizations but one. Us. We are alone.

In 1985, Sagan was especially concerned about the 55,000 nuclear warheads strategically placed around the globe, threatening to make Earth a cosmological loser. A recurring theme in these lectures is that our scientific prowess is double-edged, revealing the awesomeness of nature while landing us in great peril.

Yet this is not a dour book. Far from it. Sagan was fundamentally an optimist, and The Varieties of Scientific Experience is mostly a joyful, celebratory meditation on nature and the expansiveness of the human spirit. The volume was published on the 10th anniversary of Sagan’s death in December 1996. For those who have sorely missed his clear and wise voice, it will be received as a gift. ·

Wray Herbert writes the “Mind Matters” column for

Adam January 30, 2007 at 7:20

Hi Larry

It’s funny but I always remember Sagan’s “Cosmos” as opening my mind up enough to let in the concept of God, not slam it shut against such Big Ideas. Yet Sagan was quite right that many settle for a much more parochial God than the concept deserves.


ljk January 30, 2007 at 23:40

Carl Sagan: Science and the Search for God

Ann Druyan, Steve Soter, and Neil deGrasse Tyson

In this panel discussion with Hayden Planetarium director Tyson, Carl
Sagan’s widow and former colleague discuss the astrobiologist’s perspective
on science, the spiritual experience, and the search for God.

Go this page and scroll down:

Eric James January 31, 2007 at 0:51

A recurring theme in these lectures is that our scientific prowess is double-edged, revealing the awesomeness of nature while landing us in great peril.

This brings to mind some of the experiments in particle physics. I fear that scientists too easily dismiss these manipulations as being “too small to be harmful.” I wish they’d remeber, it was David killed Goliath.

Adam January 31, 2007 at 6:22

Hi Eric

Then again cautionary tales are sometimes just tales – “David” was probably not Goliath’s adversary since elsewhere it says Elhanan had slain the Philistine.

Propaganda was as alive back then as it is today – think of all the stupid fears over Cassini’s RTGs or ridiculous worries over Galileo’s RTGs causing a fission explosion in Jupiter when Galileo came to a fiery end. The fears over what the LHC might unleash are as ridiculous since we live at the bottom of a gigantic particle accelerator target – Earth’s atmosphere – and much higher energy particles than LHC ions smash into our atmosphere all the time, bathing us in muons but doing little else.

Here in Australia people are fretting over diverting treated sewage water back into our dams, effectively recycling it. With modern reverse-osmosis membranes the water is cleaner than our current tap-water, but plenty of people worry… “What if???” Yet none of them worry about the crap that might poison them from their own rainwater tanks.

Shall the human race fail to thrive by pandering to idiots?


Edg Duveyoung March 3, 2007 at 10:32

I just now finished Contact With Alien Civilizations — Our Hopes and Fears about Encountering Extraterrestrials by Michael A.G. Michaud. This book was suggested, above, in response to my request for something that does for today’s knowledge that Sagan and Shklovskii’s Intelligent Life in the Universe did for us “back when.”

I’m sorry to report that the book has a fatal flaw — a lack of stance. I am not exaggerating when I say that virtually every page in this book ceaselessly over-utilizes certain words and phrases, e.g. “might have,” “might not,” “likely to be,” “on the other hand,” “possibly,” “it is unknown but perhaps.” The result is this very dull compendium of possibilities — each one of which is paired with its conceptual opposite such that the reader is left without any hope of choosing one over the other — even on an intuitive basis. With Sagan and Shklovskii, I felt that I came away knowing more, having better hunches about reality, and Michaud’s book left me asking “Where’s the beef?” This book tastes like cardboard.

Certainly the book covers all the major bases, certainly Michaud quotes endlessly the various conjectures of famous minds in astronomy, and certainly Michaud honors the thoughts of science fiction writers, but I just felt it was a hard long slog to read the book. Michaud never tells us what he’d put his money on, and it turns out that that was what I wanted most from him. I so wanted this book to be another Sagan and Shklovskii epiphany.

Oh, the delicious, the tasty, the hot off the grill details are all there in the 80 pages of bibliography at the end of the book, but he just doesn’t bring “the juice” of all that scholarship to his book. I will have to read what he has read in order to get the “same hit” that I got from Sagan and Shklovskii.

So, I don’t recommend this book despite the fact that it covers the concepts.


ljk April 9, 2007 at 14:50

The current issue of Skeptic Magazine (Volume 13, Number 1) has numerous
articles about Carl Sagan on the tenth anniversary of his passing.

The table of contents can be found here:

ljk December 20, 2008 at 11:05

Alex Michael Bonnici (
Sent: Sat 12/20/08 8:57 AM

Today on Discovery Enterprise we commemorate the memory of Carl Sagan who died an untimely death twelve years ago today. Sagan was an astronomer, astrochemist, author, and highly successful popularizer of astronomy, astrophysics and other natural sciences. He pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI).

For me personally he will always be remembered and revered as a great teacher who communicated the joys and transcendence of scientific discovery. Carl Sagan’s enduring legacy will always be linked to his ability to convey the wonders of science to the general public and his skill to inspiring the next generation of scientists. Carl Sagan’s name will also be forever linked to the greatest science television series in history – Cosmos.

ljk November 2, 2009 at 17:46

This Saturday, November 7 is the first annual Carl Sagan Day, though his actual 75th birthday was on November 9 and there was a blogathon celebration for Sagan in the last few years.

ljk November 7, 2009 at 1:05

Title: Bowler, Peter J.: Science for All

Publisher: University of Chicago Press

Recent scholarship has revealed that pioneering Victorian scientists endeavored through voluminous writing to raise public interest in science and its implications.

But it has generally been assumed that once science became a profession around the turn of the century, this new generation of scientists turned its collective back on public outreach.

Science for All debunks this apocryphal notion.

For more information, see the book synopsis at:

Dorion Sagan September 8, 2010 at 18:06

Thanks for the blog and comments. Readers may be interested in my new e-book, The Sciences of Avatar: from Anthropology to Xenology, which explores the real sciences (and other disciplines) behind James Cameron’s fantastic movie. My cover uses (with permission) a very similar astrophotograph, also taken by Marco Lorenzi. I think readers and educators may find some things to ponder in this short work:

Many cheers,

Dorion Sagan

Paul Gilster September 8, 2010 at 18:45

Thank you, Dorion. A pleasure to have you here!

ljk September 9, 2010 at 1:09

Beautiful imagery accompanies Carl Sagan reading on the Pale Blue Dot:!

ljk October 3, 2010 at 8:01

In honor of the thirtieth anniversary of Carl Sagan’s Cosmos series, which first aired on PBS Television in September of 1980, here is a radio interview with Sagan from 1994 on NPR’s Science Friday:

To quote:

FLATOW: “Pale Blue Dot,” that’s always the first question that every interviewer asked an author, why the title?

Mr. CARL SAGAN (Astronomer): Well, I was an experimenter on the Voyager 1 and 2 spacecraft. And after they swept by the Jupiter, Saturn, Uranus and Neptune systems, it was possible to do something I had wanted to do from the beginning, and that is to turn the cameras on one of these spacecraft back to photograph the planet from which it had come. And clearly, there would not be much scientific data from this, because we were so far away that the Earth was just a point – a pale blue dot.

But when we took the picture, there was something about it that seemed to me so poignant, vulnerable, tiny. And if we had photographed it from a much further distance, it would have been gone, lost against the backdrop of distant stars. And to me, it – I thought there – that’s us. That’s our world. That’s all of us – everybody you know, everybody you love, everybody you ever heard of lived out their lives there, on a mote of dust in a sunbeam.

And it spoke to me about the need for us to care for one another, and also to preserve the pale blue dot, which is the only home we’ve ever known. And it underscored the tinyness, the comparative insignificance of our world and ourselves.


Mr. SAGAN: The Cola Wars. Whereas if NASA had gone on to send humans to near-earth asteroids or to land on Mars, the enthusiasm would have been maintained at a very high level. Now I don’t say that it’s NASA’s fault. NASA cannot make that decision on its own. It has to be made at a much higher level. But that decision was not made. NASA was left to its own devices, and that’s why we have a falling off of interest in the space program for excellent reasons. People aren’t stupid.

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