Our Stubborn Refusal to Give Up On Alien Life
Willy Ley, Mariner IV to Mars (1966)
“In July of 1965, as a tiny octagonal spacecraft swooped across the Martian surface, my father, who had just turned eighteen, was standing tall on a humid, hardwood-forested hill in Appalachia.” Thus begins Sarah Stewart Johnson’s Sirens of Mars. Dr. Johnson, a professor of planetary science at Georgetown specializing in extraterrestrial life, deftly weaves the history of our search for life on Mars with her own biography.
Mariner IV was the first successful Mars probe. In a brief flyby, it took temperature and pressure measurements and looked for a magnetic field. But the public interest was in the 22 photos it took. Because the Deep Space Network’s link margins were so conservative, the data rate was limited to 8 1/3 bits per second. It took eight hours for each image to be radioed back to earth, after which primitive computers assembled the data into images. In her dramatic rendering, Johnson tells how Bob Leighton, the camera’s principal investigator, impatient to know if the camera was even pointing at the planet, had engineers print out the numbers of the first image on strips of ticker-tape and paste them to a wall in a giant “paint-by-numbers” map. As they colored in their map with shades of red chalk, the Martian limb appeared, and they knew their camera had worked. JPL released the first two images, too blurry to show anything, and waited for the others to trickle in.
When frame 7 came in, Leighton stopped in his tracks. He called in the mission director and the project manager and showed them a tiny Polaroid of the image. “It wasn’t at all what they expected. They stared at the image in quiet disappointment. Eventually, Schneiderman uttered what they all knew to be true: ‘Jack, you and I have a twenty-minute jump on the rest of the lab to go out and look for new jobs.’”
And here is the only shortcoming of Johnson’s book: there are no illustrations. I suppose, these days, that’s not so important, for any of us can simply Google “Mariner IV Frame 7” and get this:
The first photograph unambiguously showing craters on Mars. Taken as a set, the photographs, along with the other data, revealed a dead, cold, cratered world.
Being an old guy, it did not immediately occur to me to Google for frame 7. Instead, I went to my bookshelf and pulled down my copy of Willy Ley’s Mariner IV to Mars, which includes it. I read this book at least twice as a teen, and Johnson’s book caused me to read it again.
Ley was a founder of the German Rocket Society that was also home to Wernher von Braun. Ley immigrated to the US before the war and became a popular science writer. His Mariner IV to Mars bears all the signs of an “instant” book. The bulk of it written well in advance of the flyby, a hasty summary written a month or two later, and then pushed out as part of the Signet Science Library paperback series, 60 cents each.
After recounting the Mariner IV flyby, Johnson loops back to cover the human history of Mars; its evolution from a moving point of light in the sky to a world, of the early telescopic observations and maps, of Schiaparelli and his “canali,” of Percival Lowell and the canal mania of the late-nineteenth and early-twentieth centuries. Along the way she provides pen portraits of the astronomers, telling us of their lives and their times.
Ley covers much of the same material, though with less style. In addition, Ley covers Mars in popular culture. This summary covers schemes for communicating with Martians and descriptions of influential science fiction novels, including Percy Gregg’s Across the Zodiac (1880), which took a hopeful view of Martians, and H.G. Wells’s War of the Worlds (1898), which decidedly did not.
Ley also gives us a better overview of the diversity of scientific views prior to the space age, describing several competing theories. One of them was the work of Svante Arrhenius, who pretty much nailed it in 1910. A Swedish chemist, he came up non-biological, chemical explanations for the colors and seasonal changes in the appearance of Mars, and a pretty good guess as to its surface temperatures.
And yet, many wanted to believe in life on the planet. Popular belief in intelligent Martians remained strong until World War II. While by 1960, no professional believed in intelligent life on Mars, many held open the possibility that the spring “wave of greening” was plant life instead of a seasonal redistribution of dust.
And then the Mariner results came in. Craters. Incredible cold. Atmospheric pressure 1% of Earth’s. A surface bombarded by intense radiation.
But Ley wouldn’t give up on the hope for plant life, writing “The problem of plant life on Mars … has not been touched by the photographs taken from space.” He then spins out several possible scenarios.
Ley was not alone. The engineers of JPL did not have to look for jobs. Instead, they built more Mars probes. The later missions (Mariners VI and VII flew by, Mariner IX orbited) showed that Mars was more than cratered wasteland. They found plains, giant volcanoes, and the huge rip in the planet known as Valles Marineris, a canyon stretching 1/3 of the way around it. They found features that had to have been carved by water. Where had the water gone? Dissociated and blown to space? Or hiding underground? Could subsurface water be supporting microbial life?
And so the pressure built to land on Mars and search for life. Viking, a pair of orbiters and landers, was sent to do exactly that. It performed a variety of investigations, but it was hyped to the public as a search for life. The search failed.
I’ve always wondered if the Viking scientists believed their own hype, or if they pushed it because of a cynical calculation that it was the only way they could get such an expensive project funded. If the latter, they were right. Viking’s failure killed Mars projects for two decades.
But the dream wouldn’t die. There were clearly fluvial features, so NASA designed a series of missions to “follow the water,” laying out the case through a series of orbiters, landers, and rovers that Mars had had conditions hospitable to life for substantial periods in the past. Investigations on earth have shown how life survives in unbelievably hostile environments, such as hot undersea vents. Johnson’s own work studies life in lakes more corrosive than battery acid.
Johnson describes these later missions and the people behind them, including her mentor, Maria Zuber, and gives us a preview of Perseverance’s mission to Jezero Crater. She weaves in her own history. As is often the case, chance played a role. She happened to get a scholarship to Washington University in St. Louis. She happened to be offered an undergraduate job in Ray Arvidson’s lab when he was working on Mars rovers. She was hooked. She tells of field trips, post-graduate studies, and her personal life, always in engaging, sometimes in moving, prose.
In a numinous closing essay, Johnson meditates on the meaning of our search for life elsewhere. She notes the impact of Enlightenment science: “With a mechanical, largely lifeless universe came a newfound existential sorrow. It meant we were potentially alone in the enormity of the now tenebrous night.” She writes of how all we know is temporary. Even the Earth itself will pass away, swallowed by the Sun. She sees the search for life as “not just the search for the other, or for companionship. Nor is it just the search for knowledge. It is the search for infinity…. It would be a shimmering hope that life might not be an ephemeral thing, even if we are.”
You probably won’t be able to find Ley’s book – it’s long out of print – but it is a fun period piece. Dr. Johnson has given us a wonderfully written, deeply personal book. I highly recommend it.
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