Cover image from http://www.librosmaravillosos.com, Carl Sagan in 1976.
To mention Carl Sagan (1934-1996) is to name that well-known scientist and writer whose wide smile lit up the space around him, and whose work in sharing science has left a deep mark on many generations. Among his many and varied contributions, the documentary television series Cosmos: A Personal Voyage (1980), which he co-authored and narrated, stands out; as does the novel Contact [1], which the 1997 film of the same name directed by Robert Zemeckis and starring Jodie Foster was based on. He also won the 1978 Pulitzer Prize for General Nonfiction for his book The Dragons of Eden [2].
In this introduction, we will get closer to the person behind a life full of successes, what his story is, and how he became who he was.
The Making of a Legend: Childhood and Adolescence.
Carl Edward Sagan was born in New York (USA) on November 9, 1934. His father, Sam Sagan, was from Ukraine and had moved to the United States, where he worked as a laborer in a textile factory. His mother, Rachel Molly Gruber, was from New York and had experienced extreme poverty as a child, having lived through the “Great Depression” of 1920. Carl was named in honor of his maternal grandmother, Chaiya Clara. He had a sister named Carol, and his childhood was spent in the simple apartment the family had in Brooklyn (New York). They were Reform Jews, and although his father was not particularly religious, his mother actively participated in services and believed in traditions, so she only served kosher meat. His father was a quiet and kind man, whose conciliatory nature led him to try to ease tensions between employers and workers in the complicated situation of industrial New York in the early 20th century. Carl himself admitted that he maintained a close relationship with them throughout his life, from whom he learned the ability to be surprised and the tendency to analyze everything, the basis of scientific thought [3, 4, 5]. Their powerful influence is evident in almost all his publications, as in the book The Demon-Haunted World, in which he states [6]:
“My parents were not scientists. They knew almost nothing about science. But in introducing me simultaneously to skepticism and to asking questions, they taught me the two modes of thought that coexist precariously but are fundamental to the scientific method.”
One of the childhood experiences that Sagan remembered most vividly was the family’s visit to the 1939 New York World’s Fair, which profoundly marked him. This event was held in Flushing Meadows, the second-largest public park in New York City after Manhattan’s Central Park. It took place from April 30 to October 31 of that year with the slogan “Building the World of Tomorrow,” and its success was such that it reopened to the public from May 11 to October 27, 1940. The boy attended it when he was four years old, and much later he would even remember the characteristic crackling sound produced when a lamp illuminated a photoelectric cell, and how, when a tuning fork was activated, the sound it generated became a wave on an oscilloscope. In addition, he saw for the first time an invention that would soon replace the radio: television, and he attended one of the events that had the greatest media impact: the burial of a time capsule in the ground of the public park that hosted the exhibition. Several memories of humanity from the 1930s were stored in it to be recovered by future generations, and this idea completely captivated Carl.
Unfortunately, that same year World War II began (1939-1945), and his family’s Jewish background made them experience it with special horror, especially after it ended and the details of the Holocaust became known. Fortunately, since young Carl was only a child, he was not very aware of what it meant, as indicated in The Demon-Haunted World [4, 5, 6].
While completing his elementary studies, he became keenly interested in natural phenomena, and to access this knowledge, his mother got him a reader’s card for the public library. The boy was very curious to know what the stars were, and since neither his parents nor any of his friends could give him a satisfactory answer [4]:
“I went to the librarian and asked for a book about stars… And the answer was sensational. It turned out that the Sun was a star but it was very close. The stars were suns, but so far away they only looked like tiny points of light… Suddenly the scale of the universe opened up to me. It was a kind of religious experience. There was something magnificent about it, a grandeur, a scale that has never left me. That will never leave me.”
Another of the institutions that vividly impressed him was the American Museum of Natural History in New York City, which he visited with a friend when he was about six or seven years old. They attended the Planetarium and observed the collections of meteorites, dinosaurs, and animals in natural environments. This interest in science continued to be nurtured by his parents, who even bought him several chemistry sets [7], although what really fascinated him were questions related to space, especially after reading the science fiction stories that were so popular at that time. These early experiences marked him for life and were the seed of his later research [4, 5].
Youth, University Studies, and Academic and Scientific Positions.
Once he graduated from Rahway High School in Rahway, New Jersey, in 1951 and passed what we call high school, he enrolled at the University of Chicago [4]. There, he participated in its astronomy club, the Ryerson Astronomical Society (RAS), whose purpose is “to observe the celestial luminaries in silence in our rooftop observatory dome on Ryerson Hall, and to spread the love of astronomy and astrophysics through talks and events” [8].
Carl Sagan in 1951, the year he graduated from Rahway High School where he completed his pre-university education. Photograph from the Rahway High School yearbook, obtained from: https://acortar.link/mFnPCu, visited on 04/25/2020.
At this university, he graduated in Arts in 1954; in 1955 he graduated in Sciences, in 1956 he earned a master’s degree in Physics, and in 1960 he received a doctorate in Astronomy and Astrophysics with the thesis titled “Physical studies of planets” [9]. Thanks to his brilliant academic record, that same year he obtained a Miller Fellowship to work at the University of California, Berkeley, which lasted until 1962, when he moved to the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. There he taught and researched until 1968, when he joined Cornell University in Ithaca, New York, where he was appointed full professor and director of the Laboratory for Planetary Studies in 1971. The following year (1972) and until 1981, he was Associate Director of the Center for Radiophysics and Space Research at Cornell, becoming the first holder of the David Duncan Professorship in Astronomy and Space Sciences in 1976, where he also offered a course in critical thinking until his death in 1996. His prestige crossed borders, and among other honors, he delivered the 1977 edition of the Royal Institution Christmas Lectures in London [10].
Proof of his innate brilliance is evident in his curriculum vitae from December 1961, where it can be seen that, in addition to already having two children at the young age of 27, he belonged to the most prestigious scientific associations and had published important cutting-edge research articles on different aspects of the Moon, Venus, meteorites, and outer space. It can also be seen that he had begun his work as a popularizer, a passion that accompanied him throughout his life [11].
Sagan belonged to the American space program from its beginnings, and thanks to his work as an advisor to NASA, the guidelines that the Apollo Program astronauts traveling to the Moon had to follow were developed, among other things. He also participated in the design of the experiments of several unmanned missions that were sent to explore the solar system. Inspired by the “time capsule” he saw as a child at the 1939 New York World’s Fair, these missions included a message easily understandable by any extraterrestrial intelligence that might find them; the first was an anodized plaque placed on the Pioneer 10 spacecraft launched in 1972, and the second, a copy of the first, on the Pioneer 11 spacecraft launched the following year (1973). Excited by the idea of connecting with hypothetical extraterrestrial civilizations, Sagan conceived the so-called “Golden Record” that was sent on the Voyager spacecraft in 1977. However, he was also critical of some NASA proposals, because he was against the funding of the space shuttle and the space station at the expense of possible future robotic missions [12].
However, despite eagerly searching for extraterrestrial life, he remained very cautious about the so-called “UFO phenomenon,” because he believed that it should be studied without restrictions by scientists to be able to establish any reliable conclusion [1].
Interested in the rigor of scientific publications, he was the editor of the journal Icarus, which specializes in studies of the Solar System from the perspective of astronomy as well as other aspects such as geology, meteorology, physics, chemistry, or biology [13].
In 1980, Carl Sagan, Bruce Murray, and Louis Friedman founded The Planetary Society [14], a non-governmental organization whose goal is to advance the space exploration of the solar system and to promote planetary sciences and astronomy. It is headquartered in Pasadena (USA), and it also manages the SETI program for the search for extraterrestrial life through radio emissions, the first of which arose under the sponsorship of NASA during the 1970s.
Carl Sagan held important positions in several prestigious American scientific societies; he was president of the Division for Planetary Sciences (DPS) of the American Astronomical Society, president of the Planetology Section of the American Geophysical Union, and president of the Astronomy Section of the American Association for the Advancement of Science, among many others [15].
His Scientific Contributions.
The numerous research articles he wrote, many of which have been compiled by his biographer William Poundstone [16], testify to the fact that he was an extraordinary scientist.
His work was fundamental in discovering the high temperatures that exist on the surface of the planet Venus, a great unknown in the early 1960s. He published his results in the book Planets [17], and according to his data, everything seemed to indicate that it was a dry and very hot planet, with a surface temperature of about 380 °C. Later, at NASA’s Jet Propulsion Laboratory, he participated in the first missions of the Mariner Program to Venus, and in 1962, the Mariner 2 probe confirmed his conclusions, determining that its atmosphere is considerably hot and very dense. His research on Venus led him to predict that a global warming of the Earth generated by human beings would be a growing danger that would lead it to have a similar evolution to that of Venus, making it unsuitable for life as a consequence of an out-of-control greenhouse effect.
Sagan was one of the first scientists to hypothesize that Titan, one of Saturn’s moons, could contain large expanses of liquid compounds beneath its surface, and he also provided an explanation for the reddish color of its atmosphere, deducing that it was made up of organic molecules.
He also suggested that Europa, one of Jupiter’s moons, might harbor underground water oceans. The existence of this ocean was indirectly confirmed by the Galileo spacecraft, which was launched on October 18, 1989, and entered Jupiter’s atmosphere on December 7, 1995. Another planet that focused his attention was Mars, because he was intrigued by the color variations on its surface, and after several studies, he concluded that they were produced by movements of surface dust caused by windstorms.
Carl Sagan was successful in almost all the research he undertook except for one: the location of extraterrestrial life, even though it especially excited him and he dedicated countless efforts to it. To this end, he experimented with the generation of amino acids through radiation and chemical reactions [18], participated in the aforementioned SETI program, and in the so-called “Arecibo message,” which was a radio transmission sent into space from the Arecibo Observatory (Puerto Rico) on November 16, 1974. It provided information about the location of the Solar System, our planet, and human beings, and was directed towards a cluster of stars located about 25,000 light-years from Earth. To this day, we have not received a response.
His Private Life, Ideology, and Popularization Work.
Carl Sagan was interested in a large number of topics that he always approached from the perspective of a scientist, and he lived in a turbulent but extraordinarily interesting era. In addition to witnessing the “Cold War” resulting from World War II (1939-1945), he saw the numerous scientific, technical, and biomedical advances that characterized the 20th century.
Carl and his firstborn Dorion. Courtesy of his first wife and Dorion’s mother, Lynn Margulis. (http://www.librosmaravillosos.com, visited on 04/25/2020).
His biographers define him as a skeptical and freethinking person, a declared agnostic, whose private life was a reflection of that era. He married three times: in 1957 to biologist Lynn Margulis, in 1968 to artist and screenwriter Linda Salzman, and in 1981 to writer and activist Ann Druyan, a union that would last until the scientist’s death in 1996. With them, he had five children: Dorion S. Sagan Margulis (1959), Jeremy E. Sagan Margulis (1960), Nicholas J. Z. Sagan Salzman (1970), Alexandra R. Sagan Druyan (1982), and Samuel D. Sagan Druyan (1991).
A brilliant popularizer of science, he tried to convey scientific concepts in a simple way so that they would reach the general public and thus end pseudoscience. His best-known work is the aforementioned series Cosmos, which was complemented by a book of the same title [19], followed by the sequel Pale Blue Dot: A Vision of the Human Future in Space [20]. The latter was inspired by a photograph of Earth taken by the Voyager 1 spacecraft at a distance of 6 billion kilometers, when it was about to leave our Solar System in 1990. Opposed to violence, he spoke out against the Vietnam War and the nuclear arms race between the United States and the Soviet Union, and due to his participation in peace protests, he was arrested several times [5].
Unfortunately, at the age of 60, Carl Sagan developed myelodysplasia and underwent three bone marrow transplants donated by his sister, but his body did not recover, and he died of pneumonia on December 20, 1996, at the age of 62. He was buried in Lake View Cemetery in Ithaca, New York [21], and the recognitions and tributes to his figure and his work have been countless, continuing to this day. Rest in peace.
IN MEMORIAM
Memorial stone dedicated to Carl Sagan on the “Walk of Fame” of the Brooklyn Botanic Garden (New York). (https://en.wikipedia.org/wiki/File:Carl-sagan-brooklyn.JPG, visited on 04/25/2020).
References
[1] SAGAN, Carl (1985) Contact. New York, Simon and Schuster.
[2] SAGAN, Carl (1977) The Dragons of Eden: Speculations on the Evolution of Human Intelligence. New York, Random House.
[3] https://www.accuracyproject.org/cbe-Sagan,Carl.html, visited on 01/02/2010.
[4] DAVIDSON, Keay (1999) Carl Sagan: A life. New York, etc, John Wiley & Sons.
[5] SPANGENBURG, Ray; MOSER, Diane (2004) Carl Sagan: A Biography. Westport, Conn., Greenwood Publ.
[6] SAGAN, Carl (1995) The Demon-Haunted World: Science as a Candle in the Dark. New York, Random House. It was continued by SAGAN, Carl (1997) Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium. New York, Random House.
[7] https://acortar.link/8PtKkD, visited on 01/12/2020.
[8] https://astro.uchicago.edu/RAS/, visited on 01/12/2020.
[9] https://acortar.link/ckChf5, visited on 01/12/2020. His thesis abstract can be consulted at https://acortar.link/6cXcuq, visited on 04/28/2020.
[10] “Christmas Lectures 1977: The Planets: RI Channel”, https://acortar.link/oVYCQs. We cannot list here the numerous awards he received, which can be consulted in any of the biographies cited here.
[11] https://acortar.link/3QEU6Y, visited on 04/25/2020.
[12] https://charlierose.com/videos/18982, visited on 01/12/2020.
[13] https://acortar.link/FszWIp, visited on 01/12/2020.
[14] The Planetary Society, https://www.planetary.org/, visited on 01/12/2020.
[15] https://aas.org/about-aas, www.agu.org, and https://www.
