Carl Sagan

Carl Sagan: A Pop Science Icon

I went to the librarian and asked for a book about stars; … And the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light … The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me.
Carl Sagan, recalling how he became interested in stars, and astronomy.

When I think of Carl Sagan, I think of a man who has made countless people interested in science, particularly in the universe. Some might describe him as a planetary scientist, or an astrophysicist, or an exobiologist(now called astrobiologist), but I’ll remember him as a pop-science icon.

Albeit he has done massive research and his contributions to the fields of astronomy, astrobiology (study of the evolution of life in the universe), and science, in general, are enormous, the masses will remember him for his activities in science communication, and popularisation of science among the general public. He co-wrote and narrated the hit television program, ‘Cosmos: A Personal Voyage’ which won an Emmy and a Peabody Award.

He was the David Duncan Professor of Astronomy and Space Sciences at Cornell University, occupying the position till his death due to pneumonia (an outcome of cancer) in 1996.

Carl Sagan in College

Carl Sagan was born in 1934 in Brooklyn, New York to Samuel Sagan, a garment worker, and Rachel Gruber, a housewife. A bright student from a young age, he was inquisitive and questioning, qualities which will lead him to tackle big questions later on.

Carl Sagan in 1994
Carl Sagan, in 1994.(Source)

Carl Sagan went to college at 16, studying until a Ph.D. at the University of Chicago. His doctoral thesis Physical Studies of Planets was submitted to the Department of Astronomy and Astrophysics in 1960.

He wasn’t like most scientists who specialized and pigeon-holed themselves to one particular area of expertise. His thoughts were very broad, and this can be seen with the variety of people he worked with while in college.

During his college years, he worked with notable individuals such as physicist George Gamow, chemist Melvin Calvin, and his doctoral advisor Gerard Kuiper. He also worked with geneticist H.J. Muller and Harold Urey, writing a thesis on the origins of life.  

George Gamow: Developed the Big-Bang Theory for the evolution of the universe.

Melvin Calvin: Won the 1961 Nobel Prize in Chemistry for work on the Calvin Cycle, a notable step in photosynthesis (the process by which plants generate energy)

Gerard Kuiper: Notable astrophysicist, who did a ton of work in the field, as well as worked on the 1960 Moon landing mission.

H.J. Muller: Won the 1946 Nobel Prize in Physiology or Medicine for the discovery of the production of mutations by means of X-ray irradiation.

Harold Urey: Won the 1934 Nobel Prize in Chemistry for the discovery of deuterium (an isotope of hydrogen). He also played a major role in the development of the atom bomb, and theories of the evolution of organic matter and life from non-living matter. 

Project A119: Nuking the Moon
A young Carl Sagan, still in college along with his doctoral advisor Gerard Kuiper was involved in the top-secret United States Air Force classified project titled Project A119.
The aim of the project was to detonate a nuke on the surface of the moon, as a show of strength during the Cold War. Carl Sagan was part of a team whose job was to figure out the outcomes of blowing up a nuke in space as well as the scientific value of the project.
The project was eventually scrapped because the military thought that it would receive criticism from the public.

Carl Sagan’s Role in Science Communication

What made Carl Sagan famous was his role in popularizing science, and his activities in science communication.

Sagan has written many popular science books including the best-selling ‘The Dragons of Eden’, ‘Broca’s Brain’, and ‘Pale Blue Dot’.

The Dragons of Eden’ won Carl Sagan a Pulitzer Prize in 1978. He also wrote a science fiction novel titled ‘Contact’ in 1978, later turned into a movie with the same name in 1997, which won a Hugo Award.

Caption: Sagan on the set of Cosmos
Sagan on the set of Cosmos (Source)

Carl’s road to what was basically stardom came when he co-wrote and narrated the 13 part television program titled ‘Cosmos: A Personal Voyage’, which eventually became the most widely watched program in the history of American television.

He wrote ‘Cosmos’, to accompany the television series and then wrote a sequel to the book titled ‘Pale Blue Dot’. The U.S. Library of Congress designated ‘Cosmos’ one of eighty-eight books “That shaped America.”

Carl Sagan was known for using the catchphrase ‘billions and billions’, usually during talk shows or ‘Cosmos’. This led to a unit of measurement named after him, called sagan. A sagan is a unit of measurement equal to at least four billion of anything.

Harold Urey

Carl Sagan’s popularity was not without criticism. Some scientists were not pleased with his work, complaining that it was non-rigorous, too grandiose, and such. Others believed that he focused less on his duties as faculty, and more on maintaining his celebrity status. Ironically, Harold Urey (pictured here) was one of his more vocal critics. (Source)

The show was responsible for popularising scientific discussions among the general masses. He wrote many books, directed at the masses in an attempt to improve the scientific discussion in people from non-science backgrounds.

Carl Sagan was a vocal supporter of scientific and critical thinking, encouraging everyone to get involved in scientific thoughts. He has inspired generations of scientists to take up the field as well as improved general discourse on science in the public sphere.

Carl Sagan’s Research

Is there life on Europa, one of Jupiter’s moons? Can we live there eventually?
Is there life on Europa, one of Jupiter’s moons? Can we live there eventually? (Source)

Sagan was associated with the U.S. Space Program since its inception, working with NASA since the 1950s. He was instrumental in the Apollo missions, as well as Pioneer 10 and 11.

He was one of the first to suggest the existence of subsurface oceans of water, on Europa, Jupiter’s moon, which could potentially make it habitable. This was confirmed by the Galileo Mission.

Sagan’s research was essential in figuring out the composition of Venus’s atmosphere. He suggested that Venus was dry and very hot, a hypothesis which was confirmed by the Mariner 2 probe to Venus.

Carl Sagan had given up his top security clearance as a protest against the Vietnam War. He was vocal against the nuclear arms race under President Ronald Reagan. He along with 5 authors described the ‘TTAPS’ model (the S stands for Sagan) which introduced the word ‘nuclear winter’ for the first time. He talked about the effects of nuclear war, publishing many books on the subject as well, in an effort to discourage the nuclear arms race and promote nuclear disarmament.

Nuclear Winter: Nuclear war will cause the dropping of global temperatures, a result of thick soot (a product of widespread firestorms) clouds blocking out the Sun. 

The Search For Extraterrestrial Life

Sagan has been instrumental in opening up the discussion of aliens and extraterrestrial life in the scientific community. He was one of the most vocal voices for the creation of SETI (Search for Extraterrestrial Intelligence), making him the most cited SETI scientist and one of the most cited planetary scientists as of 2017.

In his research on extraterrestrial intelligence, he was able to show the production of amino acids (stuff that makes up proteins) from basic chemicals, using radiation. 

In a bid to open up discussion of extraterrestrial life, he advocated for scientific discourse on the topic of UFOs (Unidentified Flying Objects). He believed that scientists should study the phenomenon at the very least because of the popularity of the issue in the public sphere, and hence dispel any falsehood.

Sagan’s Paradox:
Sagan was however very skeptical of UFOs. He believed it highly unlikely that UFOs were being piloted by extraterrestrial life. He talked about many logical and scientific fallacies in their existence. One of these is titled Sagan’s Paradox.

Using the Drake Equation, (an equation to give the number of active communicative extraterrestrial civilizations in the Milky Way Galaxy) and feeding in logical and rational values into it, he projected about one million such civilizations.

Drakes Equation
The formula for the Drake Equation (Source)

If any one civilization wanted to check up on us, at a rate of let’s say once a year, Sagan projected that the civilization would have to launch 10,000 spacecraft a year.

The energy required for this trip would be equal to 1% of the total stars, which seems to imply that there is something special about us. But how can we be special if there are one million such civilizations? The fact is pretty clear that it is highly unlikely that UFOs are being piloted by extraterrestrial life.

Messages Sent into Space

As an advocate for the search of extraterrestrial life, Sagan was instrumental in the messages sent out into space. Messages were sent out in the hope that some extraterrestrial civilizations would come across it, and perhaps hence come across Earth.

The Pioneer Plaque

The Pioneer Plaque (Source)
The Pioneer Plaque (Source)

Carl Sagan constructed the Pioneer Plaque, the physical message sent to space, aboard the 1972 Pioneer 1 and 1973 Pioneer 2 spacecraft, in case the spacecraft is intercepted by extraterrestrial life.

It included a man and woman, as well as a map showing Earth’s location in the Solar System. It also includes symbology pointing towards the Sun’s location and other galactic landmarks.

The Voyager Golden Records

The Voyager Golden Record
The Voyager Golden Record (Source)

The Voyager Golden Record, sent on both Voyager spacecraft, contains various sounds and images from Earth. The sounds include natural sounds such as wind, birds, animals, and thunder.

The sounds also include music from all across the world. Music included composers such as Bach, Mozart, and Beethoven, as well as music which was contemporary at that time. The images included scientific things, like human anatomy, DNA, but also included images depicting our culture and our civilization. Carl Sagan had a major hand to play in the creation of the Record.

This is a present from a small, distant world, a token of our sounds, our science, our images, our music, our thoughts, and our feelings. We are attempting to survive our time so we may live into yours.
– President Jimmy Carter’s Message on the Record.
Listen to the Sounds of the Earth on the Golden Record here

Arecibo Message

Carl Sagan helped Frank Drake (the person who hypothesized the Drake Equation) make the Arecibo message. The Arecibo message was an interstellar message sent in 1974 to the globular star cluster M13. It included information regarding the position of Earth and the Solar System as well as the molecular composition of DNA. The message was sent into space a single time, via frequency modulated radio waves from the Arecibo Observatory at Puerto Rico.

The Arecibo message demonstrated above has color added to highlight its separate parts. The binary transmission sent carried no color information.
The Arecibo message demonstrated above has color added to highlight its separate parts. The binary transmission sent carried no color information. (Source)

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