by Adam Lee on December 1, 2006

Between the excitement of the midterm elections and the flood of atheism-related news that has occurred this month, there was one very important date that passed almost unnoticed, but that I would be remiss if I failed to mention. Namely, November 9 was the birthday of the famous astronomer and skeptic Carl Sagan. If he were still alive, he would have been 72 this month.

Sagan’s scientific achievements were groundbreaking and hardly need me to recount them. During a time when the human species was taking its first tentative steps out into the solar system, he indisputably led the way. He was one of the primary scientific advisors on some of the earliest unmanned missions to study the planets, including the Pioneer, Viking and Voyager missions, and was the chief architect of the Voyager Golden Record that contains the images and music of our civilization, in case any extraterrestrial intelligence should happen to recover the probe millions of years in the future. He was one of the first scientists to hypothesize that Venus was boiling hot due to a runaway greenhouse effect, that Jupiter’s moon Europa contains subsurface oceans beneath a layer of ice, and that a haze of organic molecules rains from the sky on Saturn’s moon Titan, all of which turned out to be correct. He was also a well-known advocate of SETI, the Search for Extraterrestrial Intelligence, and one of the trailblazing advocates who turned it into a respectable area of scientific research in its own right.

But despite his considerable scientific achievements, Carl Sagan is best remembered as a popularizer who brought the wonder and awe of science and the importance of skepticism to the public. That this aspect of his career often outshines his prolific scientific work is a measure of just how good he was at it. He was the author or co-author of many books eloquently expressing the romance and power of scientific discovery, including Broca’s Brain, The Dragons of Eden, Pale Blue Dot, The Demon-Haunted World, Billions and Billions, and Shadows of Forgotten Ancestors, many of which are still personal favorites of mine. But the best-known of all his roles was as the host of Cosmos, an award-winning PBS television series and accompanying book whose grand sweep travels from humanity’s ancient past to the glorious diversity of life to the universe on the very largest of scales, and ends with an eloquent plea for peace and reason in the face of all the threats, mostly self-caused, that confront us. Cosmos is still the most widely viewed science documentary in the history of humanity; it is estimated that over half a billion people have seen it worldwide. I cannot think of a more worthy candidate for such an honor.

As my readers are probably aware, Carl Sagan’s life was cut tragically short. I will let this great man tell the story in his own words, in an excerpt from the last chapter of his final book, Billions and Billions:

…one morning late in 1994, Annie [Sagan’s wife, Ann Druyan] noticed an ugly black-and-blue mark on my arm that had been there for many weeks. “Why hasn’t it gone away?” she asked. So at her insistence I somewhat reluctantly (black-and-blue marks can’t be serious, can they?) went to the doctor to have some routine blood tests.

We heard from him a few days later when we were in Austin, Texas. He was troubled. There clearly was some lab mixup. The analysis showed the blood of a very sick person. “Please,” he urged, “get retested right away.” I did. There had been no mistake.

Sagan had become ill with myelodysplasia, a rare and deadly form of leukemia. The only hope for survival was a bone marrow transplant, and by a stroke of good fortune, his younger sister Cari matched in all six genetic compatibility factors that would be needed for a successful one. Sagan went through several grueling rounds of chemotherapy, radiation and transplants, but the disease recurred, a few malignant cells escaping each round of treatment to kindle a new flare-up. In the end, it seems, he triumphed over myelodysplasia; but the treatment had taken a terrible toll, and his weakened immune system could not fend off a bout of pneumonia that wracked his lungs and, ultimately, ended his life. Ann Druyan was at his side as he died, and wrote in the epilogue to Billions and Billions:

Contrary to the fantasies of the fundamentalists, there was no deathbed conversion, no last minute refuge taken in a comforting vision of a heaven or an afterlife. For Carl, what mattered most was what was true, not merely what would make us feel better. Even at this moment when anyone would be forgiven for turning away the reality of our situation, Carl was unflinching.

…For days and nights Sasha [his daughter] and I had taken turns whispering into Carl’s ear. Sasha told him how much she loved him and all the ways that she would find in her life to honor him. “Brave man, wonderful life,” I said to him over and over. “Well done. With pride and joy in our love, I let you go. Without fear. June 1. June 1. For keeps…”

The rawness of these words, written so soon after Sagan’s death, still stings my eyes even as I type this. The world is a slightly darker place without him, and though he has now been deceased almost ten years, I am often reminded of how much need we still have of him. His passing preceded, by only a few years, my discovery of his writings and my enthrallment by them. It is one of my few regrets that I never had the chance to write him a letter to let him know how much his work meant to me.

But more so, I regret knowing that he had the terrible misfortune to die before seeing so many of the wonderful discoveries humanity has made in the ten years since, many of which can be credited to his legacy. There is the Stardust mission that flew through the dusty corona of the comet Wild-2 and became the first spacecraft to return comet dust to Earth; the Wilkinson Microwave Anisotropy Probe that has revealed the most detailed picture ever taken of the cosmic microwave background radiation, conclusively determining the age and large-scale structure of the universe; the Cassini-Huygens mission to Saturn and its moons, including a lander that parachuted onto the surface of Titan itself; and the robot rovers Spirit and Opportunity, which even now are exploring Mars and uncovering astonishing evidence that, though the planet is now a freezing dry desert, it had a warm, wet, Earthlike past. Such discoveries would undoubtedly have brought Sagan much joy. I am sorrowful that he missed them, for he more than anyone else deserved to live to see them; but I find some small comfort in knowing that they at least were made, and that there are many more people eager to join the pursuit of scientific progress, some of whom were perhaps inspired to do so by Sagan himself, who will continue to raise the banner of discovery and raise our eyes to the awe and wonder of living in the cosmos.

Though many new brilliant and eloquent scientific popularizers have emerged over the past ten years, none of them match up to Carl Sagan. I mean no insult by saying so, and I trust none will be perceived. If, as the man himself said, science is a candle in the dark, then Carl Sagan’s candle burned brilliantly against that dark, glowing like a miniature sun. In that light was an eloquent hope of all that humanity could become, and a poignant reminder of how much we have in common and how insignificant the things that divide us truly are. Though we can never replace him, we can do the next best thing and carry forward the ideals he defended so powerfully. Rest in peace, Dr. Sagan. We will remember, and you have my word that we will not allow your candle to go out.