Carl Sagan –An Extraordinary Life

Junling Hu

Two robotic rovers have landed on Mars in the last few weeks. Another European spacecraft orbiting Mars has sent back pictures of potential water. We saw the sharp images of Mars’ landscape, the reddish desert with a smooth surface and scattered rocks. As the world cheered the achievement of this unprecedented exploration of red planet, I cannot help thinking about its pioneer, Carl Sagan. If he were alive today, how happy he would be! I can imagine his eloquent speech, and his colorful writing on the significance of these events. After all, this has been his dream: the dream of exploring the far-away universe, and the dream of discovering life on other planets.

In his short life, Carl Sagan was best known as an astronomer and planetary scientist. He made significant contributions to the study of planetary atmospheres, the history of the Earth, and biology in outer-space. He was a life-time professor of Astronomy in Cornell University, but he also served as a distinguished visiting scientist in JPL, and played a leading role in NASA's Mariner, Viking, Voyager and Galileo expeditions to other planets. For many years, Sagan promoted the idea of exploring life on other planets. He founded the Planetary Society, which devotes to the radio search for intelligence on other planets. One planet that particularly fascinated Sagan was Mars. In 1969, Sagan has made observations, through the space photo of Mars, that there could have been water on the Mars given its smooth surface and the valley. He further speculated that life could potentially exist on Mars, even if they are in very low-level microforms. Today, his theory is being tested.

In addition to being a scientist, Sagan was also well known as a popular science writer. His book The Dragon of Eden, which describes the evolution of human intelligence, has won him the Pulitzer Prize. In addition to 200 scientific papers and articles he published, Sagan wrote more than 20 popular books. His books covered the history of science, space exploration, the planets, and evolution on the earth. One book Pale Blue Dot: A Vision of the Human Future in Space appeared on best-seller lists worldwide. His other book Cosmos, was on The New York Times bestseller list for 70 weeks. All of his books are filled with passion and wonder. I was taken by his extreme eloquence and yet precise presentation of scientific knowledge. Sagan was also the author of a novel titled Contact, which was made into a major motion picture.

The first book I read by Carl Sagan was Broca’s Brain. It was the first time I heard about Sagan. That was in 1987, when I was a college student in China. When traveling in Beijing, I picked up the Chinese translation of this book in a university bookstore. That afternoon, I stood in the bookstore, finished the whole book. The wonder I felt was unspeakable. In his vivid description, Sagan led me through a museum, to the backroom, and to jars of human brain. There, he looked at the jar of Broca’s brain. Broca was a medical scientist and a pioneer in anthropology. Broca mapped out the human brain and today one area of our brain was named after him. Sagan described the courageous life Broca has lived, and then asked, “Is Broca in this jar? Can we retrieve his eloquent speech and his passion from those grooves in this brain?” That question deeply fascinated me. It started my quest for understanding the brain, and particularly the intelligence. Seven years later, I chose the field of artificial intelligence, and I owe the influence to Carl Sagan.

But what made Sagan most famous was his PBS TV series Cosmos. It was seen by more than 500 million people in 60 countries. Cosmos has influenced a whole generation of young viewers, who later become scientists, many of them space scientists. In this 13-episode series, Sagan brought us the wonder of universe, scientific discovery and space travel. He showed us the vast size of the universe. In our own milky Way galaxy, there are 20 billion stars, and there are more than a billion galaxies out there. Together, there are “billions of billions of stars” in this universe. While the earth has existed for 5 billions years, human beings have only existed for a million years. Our life is only a faction of the universe, and our earth is only a small planet of a medium-size star in a medium-size galaxy. The fact that the earth is not the center of Solar system, and the solar system is only at the border of Milky Way, makes us deeply humble. Yet, Sagan showed the courageous human beings in the history who dared to question the conventional wisdom and dared to search for answers. It is only through their courage, today we can finally rise to the sky and go beyond the earth.

Finally, I wan to mention that Sagan is also a social activist. During cold war, under the shadow of nuclear arm race, Carl Sagan was one of those who spoke out and pushed for an international treaty on non-proliferation. He educated the public on the danger of nuclear war, and the bad effect of global warming. In a dark age, he was the beacon who lighted up the dark sky, and beamed hope and social conscience. After the collapse of Soviet Union, Sagan was deeply bothered by many social problems. In 1992, he wrote the book The Shadow of Forgotten Ancestors. It covers the evolution of life on the earth, the evolution of human from mammals, and how we still keep the traits of our ancestors: the tendency of violence, dominance and submission, and behavior in crowdedness. Sagan intended to provide the explanation to many social problems.

Throughout his life, Sagan promoted science and truth. In his book on scientific debate of UFO’s, Sagan wrote, “There are many ideas which are charming if true, which would be fun to believe in, which are a delight to think about: reincarnation, time travel, telepathy, the ability to read someone else’s mind, and becoming one with the universe. But precisely because these ideas have charm, exactly because they are of deep emotional significance to us, they are the ideas we must examine most critically.” In his short life, Sagan has upheld this principle. Regarding the UFO debate, Sagan presented a scientific approach. Since there are reports on encountering UFOs every year, Sagan propose to assume that there is one real UFO report each year. That means we have been visited for at least a million times in the history of mankind. What’s the probability of this is true? He then calculated that there has to more than 1 million civilizations out there and each has to launch 10,000 space ships per year (during their lifetime of 10 million years), just to be able to reach the earth at least once. This is very unlikely.

Sagan died in 1996 at age 62 from leukemia. Like a shooting star, he shined and passed the sky so quickly, yet left us with brightness and enduring hope for humanistic future. His passionate pursuit of scientific truth and the unknown universe is a lasting legacy that we will carry into the

future.

-January 28, 2004