Chapter 4
INTRODUCTION
Carl Sagan
was the world’s best known scientist in the late 20th century, serving as our
guide to the planets during the golden age of solar system exploration. He was
both a visionary and a committed defender of rational scientific thinking. For
a time, he transcended the usual categories of academics to become a true
celebrity. His life illustrates both the advantages (wealth, fame, access to
the seats of power) and burdens (loss of privacy, stress, criticism from
academic colleagues) this status implies.
Sagan was propelled on his
academic and public careers by a wealth of talent, a large share of good luck,
and an intensely focused drive to succeed. His lifelong quest was to understand
the universe, especially our planetary system, and to communicate the thrill of
scientific discovery to others. A natural teacher, he loved to explain things
and never made a questioner feel stupid for asking. Although Sagan had broad
intellectual interests, his pursuit of his career left little time for other
activities: he did not play golf or follow sports, take up painting or cooking
or photography, sing or play a musical instrument, join a church or synagogue,
or watch much television or movies. His first two wives complained that he
devoted insufficient time to his marriage or his children (1). It is perhaps a
matter of personal taste whether we attribute this drive to personal ego or a
genuine commitment to educate and inspire people about science. Undoubtedly there were elements of both
motivations present.
Many physical scientists,
especially those engaged in what might be called “exploration science”, would
like to be able to communicate with the public about their discoveries.
Astronomers and planetary scientists as a group have a reputation in academic
circles for successful public advocacy, which has helped stimulate relatively
large expenditure of public funds to build observatories and support interplanetary
probes. In spite of good intentions, however, few of these scientists become
adept at the techniques of explaining
technical subjects in terms that are readily understood by the lay public. Even
fewer are willing to take the time to patiently answer journalists’ questions,
to sit still for application of makeup for television appearances, or to
faithfully return reporters’ calls even when they interrupt a meal or a lab
experiment. They might like to be great communicators, but they lack the skills
and the commitment. They also recognize that academic rewards generally come to
the best researchers, with limited honor associated with excellence in teaching
and practically none for public outreach. Sagan was different. He recognized
his talents and teacher and popularizer and decided to make such outreach a
major aspect of his career.
Born in 1934, Carl (Edward)
Sagan (2) grew up in a working-class Jewish neighborhood of New York and
attended urban public schools in New York and New Jersey. His father emigrated
to the US from Ukraine as a boy, while his maternal grandparents came from the
Austro-Hungarian Empire. As a child, Sagan read what science books he could
find, but he especially enjoyed science fiction. The University of Chicago
provided him scholarship support when he entered in 1951, and there he absorbed
the broad-based "great books" program for a liberal education as well
as pursuing his love of astronomy and biology. He continued at Chicago for
graduate work, receiving his doctorate in astronomy in 1960. After two years as
a postdoctoral fellow in biology at Berkeley and Stanford, he joined the
Harvard astronomy faculty as Assistant Professor. Denied promotion at Harvard,
Sagan moved to Cornell in 1968, becoming David Duncan Professor of Astronomy
and Director of the Laboratory for Planetary studies. Sagan married three times
(3) and had five children. He died in 1996 from pneumonia in association with a
rare blood disease against which he had been struggling for the final two years
of his life.
ACADEMIC LIFE
Although best known to the
public as a popularizer, Sagan first distinguished himself as a research
scientist. His accomplishments in research made it much easier for his academic
peers to accept him as a spokesperson for science. Sagan loved the research
process, especially when it was combined with the exploration of new worlds. As
he often noted, only one generation was privileged to grow up when the other
planets and their moons were little more than dim points of light in the night
sky, and to see them emerge as unique worlds with their own geological and
perhaps even biological history. Sagan played a major role in defining two new
disciplines: planetary science and exobiology. As a leading consultant to NASA,
he also helped chart the exploration of the solar system by spacecraft.
With academic training in
both astronomy and biology, and initially stimulated by a thesis advisor
(Gerard P. Kuiper) who shares with Harold Urey the credit for founding modern
planetary science, Sagan brought a unique breadth to the emerging new fields of
planetary science and exobiology. As early as 1963, Kuiper wrote about his
former student that “Some persons work best in specializing on a major program
in the laboratory; others are best in liaison between sciences. Dr. Sagan
belongs in the latter group”. (4)
Sagan was an “idea person”
and a master of intuitive physical arguments and “back of the envelope”
calculations. He usually left the details to others, and almost all of his
published papers were collaborations. Much of this work was done with students,
many of whom went on to become leaders themselves in planetary science. These
included James Pollack (winner of the Urey Prize for most outstanding young
planetary scientist), David Morrison (Director of Astrobiology and Space
Research at NASA Ames Research Center), Brian Toon (leading researcher on ozone
depletion and atmospheric evolution), Steven Squyres (Principle Investigator
for the forthcoming Mars Sample Return missions), and Christopher Chyba (Chair
of the NASA planetary exploration advisory committee), to name just a few.
Unlike some famous academics, Sagan set high value on proper recognition for
young scientists, and most of the papers he published have others as lead
author. On much of his later work, including the famous TTAPS paper on nuclear
winter (of which more later), his name appears last among the listed authors
(5). Throughout the 1970s and into the 80s, he also edited the foremost
professional journal in planetary science, Icarus.
Sagan’s most important early
research dealt with the atmosphere of the planet Venus. Discoveries in radio
astronomy made when Sagan was in graduate school first suggested that this
planet had a massive atmosphere and very hot surface, in contrast to previous
speculation that the climate of Venus was more Earth-like. Part of Sagan’s
thesis consisted of the first computed greenhouse model for the atmosphere, in
which the high infrared opacity of carbon dioxide and water vapor produced a
surface temperature hundreds of degrees higher than that of an airless planet.
Over the decade of the 1960s he improved these models, working primarily with
James Pollack, to develop and refine what remains to this day our basic
understanding of the atmosphere of Venus.
Mars was another planet that
interested Sagan, and with Pollack he modeled the atmosphere and developed the
idea, later verified by the Mariner 9 and Viking spacecraft, that
quasi-seasonal changes observed on the surface were the result of wind-blown
dust. He also wrote a series of papers on Jupiter, focused on atmospheric
organic chemistry.
From childhood, Sagan had
been inspired by the mystery of the origin and distribution of life. This
passion led him to study biology and develop collaborations with leading
biologists such as Nobelists Stanley Miller, Joshua Lederberg, and George
Muller. Early in his career, he received more encouragement from these
biologists than from astronomers, many of whom considered planetary studies to
lie on the fringes of respectable science, and exobiology to be beyond the
pale. A number of his early publications were in exobiology, and at various
times he speculated about life not only on Mars, but also on Venus, Jupiter,
and even the Moon. He was one of the founders of international interest in
SETI, the microwave search for extraterrestrial intelligence, although he
himself did not conduct any searches. He established a life-long collaboration
with biochemist Bishun Khare and obtained a series of NASA grants to support a
Laboratory for Planetary Studies (first at Harvard and after 1968 at Cornell)
focused on organic chemistry. Their work played an important role in
establishing the importance of organic reactions in the outer solar system,
including the possible contribution of organics from comets in creating the
conditions for life’s origin on Earth.
NASA greatly valued Sagan’s
contributions to the spacecraft exploration of the planets during its “Golden
Age” (roughly 1960-1990). He was a member of science teams selected for the
Mariner 2, Mariner 9, Viking, Voyager, and Galileo missions, among others, and
served on numerous advisory panels for both NASA and the National Research
Council of the National Academy of Sciences. With his quick mind and breadth of
vision, he was always a valued contributor to planning sessions and the “quick
look” interpretation that followed the first receipt of spacecraft data,
although the detailed measurements and modeling were accomplished later by
others. His former student Clark Chapman wrote: “A man of vivid imagination, he
keeps alive a wide variety of conceptions of planetary environments. By
suggesting often outlandish alternatives and challenging traditionalists to
disprove them, he has inspired doubts about many accepted theories. Sagan’s role
is essential for healthy science because a bandwagon effect frequently leads to
premature consensus among scientists before equally plausible alternatives have
even been thought of, let alone rationally rejected.” (6)
Sagan’s own excitement with
the process of scientific discovery is captured in the following quote, written
in the early 1970s: “Even today, there are moments when what I do seems to me
like an improbable, if unusually pleasant dream: to be involved in the
exploration of Venus, Mars, Jupiter, and Saturn; to try to duplicate the steps
that led to the origin of life on an Earth very different from the one we know,
to land instruments on Mars to search there for life; and perhaps to be engaged
is a serious effort to communicate with other intelligent beings, if such there
be, out there in the dark of the night sky.” (7)
IN PURSUIT OF FAME
At the same time he was
building up an enviable academic bibliography (8) and record of successful
students, Sagan also established a growing reputation as a popularizer of
science. His boyish good looks, resonant voice, and ability to explain
scientific concepts in terms that lay persons and students could understand,
made him a popular teacher and public lecturer. He won teaching awards at
Harvard and Cornell, and even in the busiest times of his life tried to keep
his hand in undergraduate teaching. In 1966 he first achieved some modest
national attention with his book Intelligent
Life in the Universe. The product of a unique long-distance collaboration with
the distinguished Russian astrophysicist I.S. Skhlovskii, the book presented a
fascinating dialogue between the two authors, and it sold 25,000 copies
hardbound.
The following year, Sagan
wrote an upbeat article on the potential of life on the planets for The National Geographic, and he made a
few brief TV appearances. Already it was apparent to some that Sagan sought a
broader role than that of academic researcher, a concern that contributed to
denial of tenure by Harvard University in 1967. He was also acquiring a
reputation as someone driven by intense personal ambition, happiest when he was
the center of attention. Students loved him, but some fellow academics bristled
at what they perceived as self-aggrandizement and pandering to the public. Unlike
Harvard, Cornell University was looking for faculty with a potential for
stardom, and they provided Sagan an endowed chair and the solid academic
springboard he needed for his future rise to fame and fortune (9).
In his early years at
Cornell, Sagan pursued one of the themes that motivated much of his life: the
quest to improve public understanding of the nature of science. He was a
tireless defender of rationality (some would say of scientism) and opponent of
pseudoscience. He wanted every citizen to have a "baloney detector"
as defense against sham in commerce and politics as well as science. He felt
that it was the duty of scientists and scientific societies to face these
issues squarely. This conviction led him to participate as a founding member of
the Committee for Scientific Investigation of Claims of the Paranormal (CSICOP)
and to organize two controversial public symposia at meetings of the American
Association for the Advancement of Science (AAAS).
The first AAAS symposium, in
1969, dealt with the reality of UFOs, with J. Allen Hynek and James McDonald
defending UFO studies and Sagan, Donald Menzel, and Lester Grinspoon on the
attack. The proponents on both sides of the issue were scientists, although
they adopted very different approaches to the interpretation of the many
anecdotal reports of UFO sightings. Proponents argued that even though there
was no individual sighting in which one could make a compelling case for
extraterrestrial spacecraft, the sheer volume of reports justified continuing
examination and study. In contrast, Sagan emphasized the unreliability of
witnesses, the absence of physical evidence of UFOs, and the various
alternative explanations including hallucination and self-delusion. He applied
a skeptical standard that is often associated with his name: that extraordinary
claims require extraordinary levels of evidence or proof. (10)
The 1974 AAAS symposium was
on the work of popular pseudo-cosmologist Emmanuel Velikovsky. Velikovsky's
thesis of global catastrophes caused by numerous planetary encounters within
historical times, developed in his 1950 book Worlds in Collision and other writings, was scientifically
indefensible but had attracted a wide popular following. Unlike the UFO
symposium, there were no scientists to defend these ideas (11). Rather, the
77-year-old Velikovsky himself was invited to confront his debunkers. Keay
Davidson describes the symposium as follows in his Sagan biography: "The debate would constitute, in effect, an apology
to Velikovsky [for previous slights from astronomers], giving him the
opportunity to submit his ideas to direct scientific scrutiny. The debate's
ultimate goal was not to reassess Velikovsky's ideas (hardly any scientist took
these seriously), but, rather, to reassure the public of science's basic
fair-mindedness." The confrontation of the patriarchal Velikovsky and his
young, brash critic was a clash of egos on both sides. Sagan aimed his remarks,
published in extended form in Scientists
Confront Velikovsky (12), primarily at the public and science journalists.
By most accounts he was hands-down winner. Many people credit this debate as
the beginning of the end for the Velikovsky cult, which is today reduced to a
handful of obscure cranks.
Both AAAS symposia were
widely covered by the media and contributed to a growing public recognition of
Sagan’s name. A further jump toward fame came in 1973 with the publication of
one of Sagan’s best books, The Cosmic
Connection. A wide-ranging series of essays, The Cosmic Connection was described in Science as “39 genuine, vintage Sagan dinner conversations”. This
description was more accurate than the reviewer may have realized. This book,
like all of Sagan’s, was dictated. Creating his books and popular articles this
way, Sagan simultaneously developed his unique speaking and writing styles. At
his lectures, listeners were always impressed by his carefully crafted
sentences, and by the way his talks (delivered without notes) seemed to be so
well organized. Dictation turned out to be the perfect way for Sagan to
organize his thoughts and develop his prose style simultaneously. It allowed
him to “write” while traveling or walking on the beach, and it never
necessitated his learning to type. It also allowed him to derive multiple value
from the same material, typically delivering his message in various lectures,
writing it for a magazine article (for such outlets as Parade), and using it as the basis for a chapter in one of his
books.
The
Cosmic Connection
received glowing reviews (Washington Post:
“a book that is very nearly perfect”). It also helped open the door to a medium
that Sagan seemed destined for: television. In November 1973, he was invited to
appear on the popular Tonight Show with Johnny Carson. Handsome, articulate,
informal in manner, yet enthusiastically discussing real science (and often the
latest results of NASA missions like Viking and Voyager), he captivated both
the audience and the host. Over the following 13 years, Sagan appeared on the
Carson show 26 times. No matter how pressing his other business, Sagan was
always willing to take a break and fly to Hollywood for the Tonight Show. He
considered it “the biggest classroom in history.“ And it made him one of the
best-known scientists in the United States.
In January 1974, at the time
of Sagan’s second appearance on the Tonight Show, Time did a cover story on life in the universe, in which it called
Sagan “the prime advocate and perennial gadfly for planetary exploration.” A few weeks later he published an article in
TV Guide, the largest circulation
magazine in the United States. Sagan was suddenly hot, receiving media
attention normally reserved for a select few Nobel Prize winners. He also
submitted to a feature interview for the men’s magazine Oui, an even more unusual activity for an academic.
The widely publicized Viking
landings in 1976, by two NASA spacecraft designed to search for life on Mars,
provided more exposure. In 1997, Newsweek
put his smiling face on its cover, a rare accolade for any scientist. Their
thumbnail sketch stated: "At 42, Carl Sagan has become the leading
spokesman and salesman for the new science of exobiology, the search for
extraterrestrial life. Lobbying in Washington, appearing on television talk
shows and teaching at Cornell, he is building fresh support for the space
program and fulfilling his own fantasies of finding life out there. But some
colleagues are exasperated by his freewheeling speculations and question
whether the life search is a science at all. " (13)
SHOWMAN OF SCIENCE
Sagan’s next major book was
published in 1978. The Dragons of Eden
was a departure, dealing with an area of science in which he had no special
expertise: the human brain. Here Sagan popularized the work of others,
primarily Paul MacLean and his theory of the triun brain, and Roger Perry with
his concept of a brain split between right and left sides. Perhaps to
compensate for his lack of primary knowledge, Sagan worked unusually hard on
both content and writing style. Although criticized by many academics as
shallow and speculative, the book was hailed for the clarity and charm of its
prose, its wit and elegance. In 1978, The
Dragons of Eden won the Pulitzer Prize for nonfiction.
With this exposure, Sagan
decided to test the capacity of television to bring science to a mass audience.
In partnership with engineer and entrepreneur Gentry Lee, a Viking colleague,
he formed Carl Sagan Enterprises and began marketing a television series
modeled on Jacob Bronowski’s Ascent of
Man. They developed a script, raised several million dollars in support,
and hired Bronowski’s director, Adrian Malone. At the same time Sagan fell
rapturously in love with Ann Druyan, with whom he worked closely for the rest
of his life. He and Annie moved to Los Angeles, and production at KCET Public Television
started in 1977 on the 13-hour series called Cosmos.
His duel commitment to Annie
and to Cosmos eclipsed Sagan’s
academic roles. His classes were canceled, and several graduate students who
had come to Cornell to work with him chose other advisors instead. Colleagues
complained, and there was an effort to force his laboratory out of the Cornell
Space Science Building. Meanwhile, his divorce turned into a squalid and
expensive legal battle. In Los Angeles, clashes of will between Sagan and
Malone almost derailed the entire Cosmos
effort. (14) Finally, the first production aired in September 1980, accompanied
by a promotional effort that exceeded anything seen before in public
television. Most reviews were enthusiastic, and suddenly Sagan was a celebrity.
The series won the Peabody Award, and eventually more than 400 million people
saw Cosmos in dozens of countries
around the world. The accompanying book, also called Cosmos, was on the New York
Times best seller list for 70 weeks and made him wealthy as well as famous.
In October, 1980, Sagan
appeared on the cover of Time, shown
wading in the “cosmic ocean”. Time
described him as the “Showman of Science” and the “prince of popularizers”.
They wrote: “Sagan sends out an exuberant message: science is not only vital
for humanity’s future well being, but it is rousing good fun as well. Watching
with wonder -- and no doubt a little envy -- the whirling star named Sagan,
some of his colleagues feel that he has stepped beyond the bounds of science.
They complain that he is driven by ego. They also say that he tends to
overstate his case, often fails to give proper credit to other scientists for
their work and blurs the line between fact and speculation. But they probably
represent a minority view. Most scientists, increasingly sensitive to the need
for public support and understanding of science, appreciate what Sagan has
become: America’s most effective salesman of science” (15)
Sagan moved back to Cornell
after Cosmos, but he could not return
to the anonymity of the campus, even if he wanted to. People stopped him on the
street and interrupted his meals in restaurants to tell him how much they liked
Cosmos or to ask for his autograph.
He also received crank calls and death threats, requiring police patrols of his
home and prompting the University to remove his name from his office door and
from the Space Science Building directory. But fame had its positive elements.
His standard speaking fees rose toward 5 figures, and he demanded first class
airfare and private limousine service. He bought a spectacular home modeled on
an Egyptian temple, perched on the edge of one of Ithaca’s wooded gorges. The
Sagans hired a nanny and a housekeeper, and a full time secretary just to
answer letters from the public. And he received an unprecedented advance from
Simon & Shuster of $2 million for a science fiction novel to be called Contact, before he had written a word. Contact was published in 1985, and it
was made into a successful film staring Jodie Foster, released in the year
after his death.
In his continuing defense of
scientific thinking, Sagan's fame brought him a unique role, as described by
journalist Joel Achenbach in Captured by
Aliens. Achenbach noted that once Sagan achieved superstardom with Cosmos, he became the public lightning
rod for both the science and the pseudoscience of extraterrestrial life. As the
“keeper of the gates” who effectively defined the border between science and
pseudoscience. he was actively courted by many fringe figures who sought in his
blessing a legitimization of their interests or beliefs. Sagan’s role is
especially interesting because he himself was accused of straying beyond the
limits of proper science in his pursuit of evidence for life on other planets
and his defense of SETI. As Achenbach argues, it was precisely because of his
apparent open-minded attitude toward fringe topics that many on the fringe
became so bitter when Sagan turned against them. (16)
Thanks in part to his mastery
of the television medium, Sagan was moving into a world of celebrity where no
academic had gone before. He told colleagues that he intended to return to the
life of a professor, teaching again and becoming involved with NASA’s ambitious
new Galileo mission to Jupiter, but this was not enough. He also wanted to use
his new wealth and power to accomplish objectives of more global scope.
MAKING A BETTER WORLD
Sagan’s rise to celebrity
occurred simultaneous with the Ronald Reagan presidency and an escalation of
arms spending and cold war rhetoric (17). He was an early opponent of Reagan’s
Space Defense Initiative (SDI) or “Star Wars”, and he was able to rally vocal
objections from the academic community that questioned both the technical basis
for SDI and its potential destabilizing effect on the nuclear balance. Then in
1982, an even more compelling opportunity presented itself to campaign for
nuclear disarmament, thanks to research involving two of his former students,
Jim Pollack and Brian Toon.
Toon and Pollack were
research scientists at NASA Ames Research Center. With colleagues Rich Turco
and Tom Ackerman, they were studying the role of dust and atmospheric aerosols
in determining global climate. They had been working for several years to
understand the effects of martian dust storms and of the dust cloud that
enveloped the Earth following the asteroid impact that caused the extinction of
the dinosaurs. But in 1982, they had realized that smoke, especially from
petrochemical fires, would have a much greater effect on global climate than
naturally occurring dust. In fact, it appeared that the smoke from as few as
100 burning cities, when lofted into the stratosphere, could lead to severe
global cooling (nuclear winter). Turco and Toon flew to Ithaca in late 1982 to
enlist Sagan’s aid, for both the technical aspects of the research and as a
means to overcome objections that had been raised within NASA because of the
political implications of this work. This collaboration generated the TTAPS
paper (named for the first initials of the authors, but with obvious symbolic
significance) on nuclear winter published in Science in late 1983. The TTAPS authors concluded that even a
less-than-full-scale nuclear exchange, especially if it were directed against
cities, could cause global cooling and collapse of agriculture. The massive
loss of life would hit victor, vanquished, or non-combatant nations alike.
Sagan used all his prestige
to argue that these new findings rendered nuclear war obsolete and undermined
the concept of massive nuclear retaliation (18). The debate was international,
with especially strong reactions from countries that had tried to remain
outside the cold war rivalries. Apparently the issue was also widely debated
within the USSR, stimulating a rethinking in their military on nuclear
war-fighting strategies. But the pro-nuclear forces in the United States
counter-attacked vigorously, and they were more than willing to vilify Sagan
personally in the process. The National
Review called nuclear winter “a fraud” and titled one cover story
“Flat-Earth Sagan Falls off the End of the World”. Edward Teller, who at 73 was
probably the second best known scientist in the US (19), debated Sagan on
nuclear winter before a special convocation of the US Congress. Sagan also led
a delegation to meet with Pope John Paul II, who subsequently issued a Papal
statement against the build-up of nuclear arsenals. Fortunately, the accuracy
of the nuclear winter models has never been tested experimentally, but many
people credit this theory, and its advocacy by Sagan, as influential in the
move toward nuclear disarmament represented by the START treaties between the
US and the USSR.
In parallel with its
escalation of the nuclear arms race, the Reagan administration cut back
drastically on NASA’s program of planetary exploration. In 1981 they threatened
to close down the highly successful Voyager 2 spacecraft before its Uranus and
Neptune encounters and to turn JPL into a defense contractor lab. After the Shuttle Challenger accident in 1986, the
momentum seemed to have left NASA, just when Sagan was advocating an
accelerated exploration program in his books and lectures. At the same time the
USSR, under the influence of Michael Gorbachov’s reforms, seemed more open to
international collaboration. Operating a series of space stations culminating
in Mir, they tested the ability of
humans to live and work for long periods in space, and their new Energia rocket
was coming into production. Such a huge rocket was needed for only one thing
really: human flights to the Moon and planets (20).
Sagan saw an opportunity to
achieve two goals of noble dimension. By working together on missions to Mars,
the US and the USSR could build confidence and gain experience that would
ultimately defuse the cold war and permit cooperation in many other areas. By
pooling their resources, these two space-faring nations could accomplish
together what neither could afford alone -- extending human presence into the
solar system. A joint Mars program could open the door to the planets and
simultaneously ensure peace on Earth.
Sagan was perceived as an
enemy by the Pentagon and the Reagan White House. Sensing a better opportunity
in the USSR, he became a frequent visitor to Moscow in the mid 1980s. He formed
a close working relationship with Roald Sagdeev, the Director of the Space
Research Institute in Moscow, and together they opened up the Soviet planetary
exploration program, with unprecedented live reporting of the VEGA flybys of
Comet Halley in 1986. In 1987, he led an American delegation to a celebration
of the 30th anniversary of the first Sputnik, in which the Russians chartered
one of their new wide-body Ilushyn airliners to provide direct service from
Washington to Moscow. He associated with Soviet Cosmonauts and government
officials as well as scientists. For a few years, under his leadership,
anything seemed possible. Then the USSR disintegrated, and many of her space
scientists found themselves unemployed. With the failure of Russia’s last three
planetary missions (all destined for Mars), both the motivation and the
capability of Russia to partner in exploration of the solar system evaporated
(21).
By the time of the final
Voyager encounter with Neptune in 1989, it was apparent that his campaign to
promote human expansion to Mars was doomed. Sagan’s Russian friend Sagdeev was
emigrating to the US and marrying (of all people) Dwight Eisenhower’s
granddaughter. And after a decade of budget cuts, NASA seemed unable to summon
the resources even to maintain a modest program of robotic space exploration. The
high hopes of the Viking and Voyager era were gone. In a 1989 lecture at JPL,
Sagan could not conceal his frustration and disappointment. However, worse
personal blows were about to fall.
DISAPPOINTMENT AND RENEWAL
In the autumn of 1990, Sagan
made his worst scientific mistake. Iraq had invaded Kuwait, and US President
George Bush was forging a military alliance to repel the aggressor. Kuwait is a
major oil producer, and Iraq threatened to set fire to the oil wells. Sagan
became concerned that the quantity of petrochemical smoke generated by these
oil-field fires could generate a small-scale nuclear winter, endangering crops
across Asia and threatening world food production. Of his four TTAPS
co-authors, only Turco supported this hypothesis; Pollack, Toon and Ackerman
could not see how sufficient smoke could get into the stratosphere. Driven
perhaps by hubris, Sagan went public with dire predictions. In fairness, he was
careful to keep his predictions conditional, saying only that we could not show that massive oil-field fires
would not have major climatological
consequences (a “double negative” logic that he frequently used in his writing
and lecturing). In the event, the oil fields were torched in January 1991, the
smoke blackened the sky over most of Kuwait and disrupted the coastal
ecosystem, but there were no climatic effects, even on a local scale. Sagan was
widely criticized, and the episode had the further effect of undermining the
credibility of the entire nuclear winter scenario. Toon and Pollack were
especially disillusioned.
The next year Sagan was
nominated for membership in the National Academy of Sciences. Nobel laureate
Stanley Miller was his chief advocate. Academy membership requires
distinguished research scholarship, but that is rarely enough by itself to
ensure membership. Considerable weight is also given to public service, as well
as more political factors such as where you work and who you know. Most
colleagues agreed that Sagan’s research record was adequate if not compelling
(22), and that his additional journal editorship, government service, and
contributions to public understanding of science should have ensured his
election. But Sagan had made enemies and inspired jealousy too. He was
blackballed in the first voting round, requiring a full debate and vote by the
Academy membership. In the final vote he barely received 50% yes votes, far
short of the 2/3 majority required for election to membership (23). This
decision was widely reported, and Sagan received considerable public and media
support, but such outside “interference” in Academy business probably further
alienated the members. It was unheard of for the secret deliberations of the
Academy to be discussed openly in newspapers and on television.
Two years later, the National
Academy awarded Sagan its prestigious Public Welfare Medal, perhaps in partial
compensation for his rejection in 1992. The damage was done, however: not only
a stinging personal blow, but also an attack on his credibility as a
spokesperson for science. For all his accomplishments, or perhaps because of
some of them, influential members of the academic "old boys" network
never accepted him.
Other problems multiplied. In
1993 the NASA SETI Program, which he had defended on critical occasions in the
past, was abruptly terminated by Congress at the instigation of a single member
of the US Senate, Richard Byran of Nevada. His book on nuclear winter, written
with Turco, sold only a few thousand copies; no one cared much any more about
issues of nuclear war. Perhaps worst of all, a book that he and Annie put a
great deal of themselves into, Shadows of
Forgotten Ancestors, did not receive the enthusiastic welcome they
expected. Although some reviewers consider it one of Sagan’s best works, it was
not a best seller, and the prestigious New
York Times didn’t even bother to review it.
Perhaps Sagan’s most
important contributions in his final years were in his fight against the
flimflam of pseudoscience. Throughout the last decade of the millennium, this
scourge of public irrationality grew, in astrology, alien abductions,
alternative medicine, and any number of other “new age” and “millennial” fads
and cults. Sagan had a “bully pulpit” to fight back, and after the death of his
friend Isaac Asimov, his was the principle voice in defense of scientific
reason in the United States.
His most influential platform
was provided by the weekly magazine Parade,
one of the two most widely read publications in the US (24). His column
appeared there regularly for more than a decade, providing a unique opportunity
for outreach and education. In this column, he discussed the latest discoveries
in science, debunked the purveyors of flimflam, and also delved into sensitive
topics of public concern such as abortion and animal rights. His articles in Parade provided the basis for many
chapters in his final three books, Pale
Blue Dot (its title based on the distant Voyager photo of Earth (25)) The Demon Haunted World, and Billions
and Billions. The Demon Haunted
World, subtitled Science as a Candle
in the Dark, was a passionate defense of science against pseudoscience and
irrationality, as illustrated in the following
quotes. "It is far better to grasp the Universe as it really is than to
persist in delusion, however satisfying and reassuring [that may be]…
Superstition and pseudoscience keep getting in the way [of understanding
nature], providing easy answers, dodging skeptical scrutiny, casually pressing
our awe buttons and cheapening the experience, making us routine and
comfortable practitioners as well as victims of credulity… [Pseudoscience]
ripples with gullibility. . . The tenants of skepticism do not require an
advanced degree to master, as most successful used car buyers demonstrate. The
whole idea of democratic application of skepticism is that everyone should have
the essential tools to effectively and constructively evaluate claims to
knowledge…. But the tools of skepticism are generally unavailable to the
citizens of our society….Those who have something to sell, those who wish to
influence public opinion, those in power, a skeptic might suggest, have a
vested interest in discouraging skepticism."
Although more demanding and
hence less popular than his books about astronomy and planetary exploration, The Demon Haunted World is considered by
some to be his most mature and valuable publication. Expressing his concerns
about the irrationalsm that seems to pervade modern society, he wrote: “I know
that the consequences of scientific illiteracy are far more dangerous in our
time than in any time that has come before. It’s perilous and foolhardy for the
average citizen to remain ignorant about global warming, say, or ozone
depletion, air pollution, toxic and radioactive wastes, topsoil erosion,
tropical deforestation, exponential population growth ... How can we affect national policy -- or even
make intelligent decisions in our own lives -- if we don’t grasp the underlying
issues? ... Plainly there is no way back. Like it or not, we are stuck with
science. We had better make the best of it. When we finally come to terms with
it and fully recognize its beauty and power, we will find, in spiritual as well
as in practical matters, that we have made a bargain strongly in our favor.”
By this time it was also
possible to judge Sagan's influence through his many students. I have already
referred to his doctoral students who became leading researchers in planetary
science. In addition, he served as a role model in his commitment to education,
scientific skepticism, and public outreach. For example, in addition to their
research-based Ph. D.s: Clark Chapman wrote two excellent trade books and a
regular magazine column on space science; Chris Chyba became a White House
Fellow and later the Co-Director of the Stanford University Center for International
Cooperation and Security; David Grinspoon wrote a widely praised book on Venus;
Steven Soter worked on the staffs of the Smithsonian Air and Space Museum and
the American Museum of Natural History; and David Morrison became a successful
author of college textbooks in astronomy and planetary science. In addition,
there are countless others in all walks of life who credit their interest in
science to Sagan, as a teacher, author, or television personality.
Sagan's influence and example
also contributed to increasing efforts by scientists to reach out to the press
and the public. By the 1980s such professional organizations as the American
Astronomical Society and the American Geophysical Union had appointed full-time
press officers and were sponsoring press conferences at their annual meetings.
NASA missions also undertook to identify and encourage project scientists to
speak with the press, both informally and as official NASA spokespersons. In
the 1960s, Sagan was almost alone in his work with the press, but such activity
had become relatively common among space scientists two decades later.
The middle 1990s saw
restoration of Sagan’s influence on NASA. Dan Goldin, who became NASA
Administrator in 1993, came from the same tough New York Jewish background as
Sagan. Although their personalities were very different, they got on well, and
Sagan advised Goldin as he worked to reinvigorate NASA and redirect its goals
toward research and development (26). In particular, Sagan helped inspire
Goldin’s personal commitment to eventual human flight to Mars.
These were also turning into
Sagan’s twilight years (27). Except for a few meetings with Vice President
Gore, he was no longer a celebrity. The Johnny Carson show was long gone, and
his books no longer made the best seller lists. Then, in late 1994 Sagan was
diagnosed with a rare blood disease called myelodysplasia. He was told that
without massive intervention he would be dead in six months, and even with the
best care modern science could muster, his chances of survival were no more
than even. He fought back bravely and for a time seemed to have conquered the
disease, but in the end he succumbed, surrounded by his family, in December
1996.
Cornell's well-respected
President Frank Rhodes summarized his impact: "I want to salute Carl Sagan
… as the embodiment of everything that is best in academic life … in
scholarship, teaching, and service … Carl is an inspiring example of the
engaged, global citizen … [He is] a master of synthesis, and he has used that
skill to engage us as a society in some of the biggest issues of our time… With
the conscience of a humanist and the consummate skill of the scientist, he
address the needs of the society in which we live, and we are the richer for
it." (28)
Three years after his death,
it is clear that Sagan has no successor. While there are many other scientists
who are also outstanding teachers and can explain things well to lay audiences,
they lack his charisma and exposure. Or they follow a full-time media career,
such as Bill Nye ("The Science Guy"). Sagan was unique is being both
a respected research scientist with a chair at a major university, and also a
public figure and media star. In a time of increasing specialization, we may
never again see an academic who bridges these two worlds so effectively.
Endnotes:
(1) Most of the personal and historical
sources on Sagan's life are described and documented in two excellent recent
narrative biographies: Carl Sagan: A Life
by Keay Davidson, 1999, John Wiley 450pp; and Carl Sagan: A Life in the Cosmos by William Poundstone, 1999, Henry
Holt and Company, 560pp.
(2) Sagan never used his middle name or
initial -- a practice that is prevalent among actors and politicians, but less
common among scientists, who usually sign their papers with a middle initial.
(3) Sagan's first wife, Lynn (Alexander)
Margulis, became a leading biological scientist, elected to the National
Academy of Sciences and awarded the nation's highest science honor, the
Presidential Medal of Science.
(4) Kuiper, quoted by Davidson in Carl Sagan: A Life.
(5) In Sagan’s professional disciplines
the order of authors (if not alphabetical) is generally expected to reflect
their relative contribution. Only a few senior researchers routinely place
their names last in multi-author papers.
(6) Chapman, quoted by Davidson by Carl Sagan: A Life.
(7) The
Cosmic Connection: An
Extraterrestrial Perspective, 1973, Doubleday 274 pp (re-issued by
Cambridge University Press, 2000)
(8) He kept a meticulous record of all
his lectures and popular articles as well as his scientific appointments and
publications, generating a Vitae at
the end of his career that stood about 4 cm high -- the equivalent of a small
book in length.
(9) Cornell University President Frank T.
Rhodes said at Sagan's 60th birthday that "I want to bring Carl greetings
from all the members of the Cornell Community who owe so much to his leadership
over so many years. . . and thank you .
. . as an exemplary member of the Cornell community. . . I want to salute Carl
Sagan tonight as the embodiment of everything that is best in the academic life
and to explain why we are so immensely proud to be able to call him colleague
here at Cornell." In Carl Sagan's
Universe, Yervant Terzian and Elizabeth Bilson, editors, 1997, Cambridge
University Press 232 pp.
(10) Sagan himself was always fascinated by
the possibility of life on other worlds, and during his high school and college
years he was attracted to the idea that UFOs might be visiting spacecraft.
Later his scientific skepticism overcame such romantic delusions, but perhaps
Sagan retained some empathy with the UFOlogists at the same time he criticized
their naïve interpretation of flimsy and fragmentary data.
(11) Some critics
from outside the physical sciences still question how Sagan and other
astronomers could reject Velikovsky without reading his books and carefully
studying his ideas. Perhaps they don't understand how readily someone with
sound technical training and physical intuition can recognize pseudoscience
like that of Velikovsky. You don't have to consume an entire meal of spoiled
food to recognize the problem -- one or two bites is enough.
(12) Scientists
Confront Velikovsky, edited by Donald Goldsmith, 1977, Cornell University
Press 183 pp. Velikovsky refused to publish his paper in the book because he
was unwilling to agree to refereeing, page limits, or other editorial controls,
so we have no verbatim record of his side in this "debate".
(13) Newseek,
August 15, 1977.
(14) Friends and critics alike agree that
the biggest problem with Cosmos lay
in repeated close-up shots of Sagan, often gazing rapturously into the void.
Some of Sagan's friends blamed these on Malone and suggested that the Director
included these shots to make Sagan look foolish. Malone said they were Sagan's
idea, and Sagan did not realize until the series was aired that they detracted
from his image rather than enhancing it. Later Gentry Lee cut the Cosmos series for commercial television,
eliminating most of the Sagan close-ups to produce a more focused, faster-paced
product.
(15) Time,
October 20, 1980. Sagan also was on the cover the United Mainliner magazine in December 1980, with the ambiguous
heading "Pied Piper of Science".
(16) One account of Sagan’s “gatekeeper” role
is recounted by Achenbach in Captured by
Aliens: The Search for Life and Truth in a Very Large Universe (1999, Simon
and Shuster 415 pp). Achenbach interviewed Richard Hoagland, author of The Monuments of Mars and leader of the
“Face on Mars” cult. Hoagland explained that in a public meeting in 1985, Sagan
made a comment that those planning NASA missions to Mars should be open to
discovering the unexpected. The statement seems innocuous to me, but according
to Hoagland, when Sagan made these remarks, he briefly made direct eye-contact
with Hoagland, who was among the journalists in the audience. Sagan’s innocent
comment thus became a coded message encouraging Hoagland to pursue his advocacy
of an artificial origin for the Face.
Hoagland argued to Achenbach that this “endorsement” legitimized his
continuing crusade, even after the Mars Global Surveyor obtained
high-resolution photos that dispelled any possibility of an artificial origin
for the Face. (Hoagland’s response was that the NASA pictures were faked, one
of the massive government cover-ups so often cited by people on the fringe).
(17) The 1980 Time that featured Sagan as
"Showman of Science" also notes on the cover a pre-election profile
called "The Real Reagan".
(18) In this period, while attending a
meeting of the imaging science team for the Galileo spacecraft, Sagan
apologized to his teammates about his inability to commit more time to this
mission by saying that he was "putting most of my energy into saving the
world from nuclear holocaust". Most team members agreed that this effort
should indeed have a higher priority for Sagan than planning imaging sequences.
(19) Years later Teller told me a story of an
airport breakfast that he and Sagan shared at this time, where (to Teller's
obvious distaste) three strangers came up to ask Sagan for his autograph, but
no one seemed to recognize Teller.
(20) Two 1987 news magazine covers capture
the mood: Newsweek (August 17)
"Lost in Space: How to get America off the ground"; and Time (October 5) "Moscow Takes the
Lead [in space exploration]"
(21) The missions were Phobos 1 and 2 in the
late 1980s, and Mars 96.
(22) Michael Shermer presented in Skeptic (spring 2000) an objective
comparison of Sagan's credentials with that of several well-known members of the
Academy, finding that by most measures of academic success (for example, his 23
honorary doctoral degrees) he ranked high, even in this august company.
(23) Jim Pollack's case may have also
confused matters. Most planetary scientists assumed that Jim would be elected
to the Academy any time, and many of Sagan's best research papers were
collaborations with him. Unfortunately, Pollack died of bone cancer in 1994,
before he was formally proposed for election to the Academy.
(24) Sagan first appeared on the cover of Parade on October 2, 1983, with an
article titled "What We Learn from Other Worlds".
(25) Sagan was the chief architect of this
experiment, turning the Voyager cameras back toward the Sun to obtain an image
of the entire solar system. Like the plaques and videodiscs he designed for the
Pioneer 10 and 11 and the Voyager 1 and 2 spacecraft, this photo was a symbol
for humanity's first tentative reach toward the stars. Unlike most scientists,
Sagan saw the value of such symbols and exploited them to stimulate public
interest in space exploration.
(26) By the time of Sagan's death, NASA's
launch rate of robotic science missions had jumped from a low of one or two per
year up to nearly ten per year.
(27) One of the highlights of his last years
was a festive 60th birthday celebration held at Cornell with four half-day
symposia honoring his contributions in four disciplines: planetary exploration,
life in the cosmos, science education, and environmental and public policy.
(28) In Carl
Sagan's Universe, Yervant Terzian and Elizabeth Bilson, editors, 1997,
Cambridge University Press 232 pp.