THE SIRENS OF MARS
Searching for Life on Another World
By Sarah Stewart Johnson
THE SMALLEST LIGHTS IN THE UNIVERSE
By Sara Seager
In 2013, the House Committee on Science, Space and Technology asked three prominent scientists whether life — aliens, if you wish — exists beyond Earth.
“Do the math,” said Sara Seager, an astrophysicist from M.I.T.
Ralph Hall, a 90-year-old congressman from Texas, said he couldn’t do the math; that was the problem.
The math actually isn’t all that complicated. The universe brims with galaxies, a couple hundred billion at least, and each of those galaxies brims with billions of stars. Planets — called exoplanets — orbit most of those stars. As of this writing, we have confirmed the existence of 4,197, but astronomers detect another exoplanet seemingly every few days. Some are gigantic and insanely hot; some have big puffy atmospheres; some climb up over and slip under their stars in polar orbits; some have “years” that last only days.
The universe overflows with worlds. In our galaxy alone, there are probably about 40 billion planets that could support life. To assume that ours is the only one that hosts living things seems a tad self-absorbed, doesn’t it?
Congressman Hall asked, “Is there life out there?”
“Yes,” said Mary Voytek, an astrobiologist at NASA.
“Yes,” said Steven Dick, a science historian at the Library of Congress.
“Yes,” said Seager.
Aliens might not be little green people, of course: They might be based on silicon or ammonia, rather than carbon; they might use cosmic rays as an energy source; they might be ghostly microbes paddling around sulfuric pools. As Seager urges in her stark, bewitching new memoir, “The Smallest Lights in the Universe,” we have to shake loose “of our Earth-based biases — our ‘terracentrism,’ … that peculiar blindness born of being human.”
Or as the Georgetown planetary scientist Sarah Stewart Johnson puts it in her own lovely memoir, “The Sirens of Mars: Searching for Life on Another World,” “It’s one of our biggest intellectual and practical challenges — like trying to imagine a color we’ve never seen.”
In “The Smallest Lights,” Seager begins with her almost feral childhood in Toronto, roving streets and tending younger siblings, often alone, by her own admission, “small and silent” and “wired a little differently.” At 15 she wandered into a University of Toronto presentation about a supernova and “sat enthralled in the pin-drop quiet, ravished by an amazing tale of discovery.” She promptly threw herself into advanced math and canoeing with equal gusto, fell in love with a paddling partner named Mike, attended graduate school at Harvard, was awarded a position at the Institute for Advanced Study in Princeton, N.J. and developed a new technique for detecting exoplanets and analyzing their atmospheres. Tenured at M.I.T. by the time she was 36, she commenced a lifelong hunt for a second Earth.
Then Mike got sick and died, and Seager, now a widowed mother of two, came unglued. The merciless seesaw of her grief makes for harrowing reading. “Hour by hour,” she writes, “I felt either broken or bulletproof.” In time, a group of six other widows, meeting every other Friday, “moving from house to house like emotional squatters,” gradually helped Seager return to the world.
The second half of her story gleams with insights into what it means to lose a partner in midlife, and just as the widows helped Seager feel less alone, her story is sure to help any readers grappling with a similar loss. “When you lose someone,” she writes, “you don’t lose them all at once, and their dying doesn’t stop with their death. You lose them a thousand times in a thousand ways. You say a thousand goodbyes. You hold a thousand funerals.”
Johnson’s “The Sirens of Mars” oscillates between a history of Mars science and an account of the author’s own journey as a planetary scientist seeking sparks of life in the immensity. She presents efficient thumbnails of astronomers like Percival Lowell, who popularized the idea of visible “canals” on Mars as evidence of an alien civilization; Carl Sagan, who suggested that big, turtlelike organisms “are not only possible on Mars; they may be favored”; and Maria Zuber, the only woman among the 87 investigators on the 1996 Mars Global Surveyor science team. Along the way, you come to appreciate the astonishing ingenuity required to safely send rovers the size of Mini Coopers several hundred million kilometers through a frozen vacuum, land them on another planet and drive them around by remote control.
Most compelling are Johnson’s memories of formative moments, as a young girl prowling roadcuts for fossils with her father, as a wide-eyed graduate student entering the Jet Propulsion Laboratory for the first time (“It felt holy to be in those rooms”) and as an awed young scientist in Copenhagen holding in her hands bacterial cells 20,000 times older than she is. Johnson remembers feeling odd when, as a college sophomore, she attended a lecture by Zuber. “My back straightened as it became clear what I was responding to,” she writes. “It was the first time I’d ever heard a woman give a planetary science talk.”
If Johnson’s prose swirls with lyrical wonder, as varied and multihued as the apricot deserts, butterscotch skies and blue sunsets of Mars, Seager’s is rawer and starker, full of blues and blacks, written in the ink of grief, suffering, healing and — ultimately — clarity. In Seager’s hands you’re as apt to learn about “a special body bag that’s designed to slide down stairs” as about storm-wracked rogue exoplanets where it rains molten iron.
Both books beautifully dramatize the emotional precarity of having one’s career pinned to the fate of space hardware. Both address the challenges of being female physical scientists in a male-dominated field, and both convey the struggle of operating in the vast scales of the universe at work, then commuting home to operate in the humbler scales of the domestic sphere. “I was constantly torn in two, always some form of distracted,” Seager writes. Johnson, after spending her workday tending to a Mars rover millions of kilometers away, hurries to pick up her kids at preschool. “It feels almost impossible to leave,” she says, “one love tearing me from another.”
Spoiler alert: Neither book ends with the exultant discovery of extraterrestrial life. In Johnson’s final pages you find yourself spiraling through Herodotus and Euclid; in Seager’s you watch her learn how to love again. But these are not disappointments — on the contrary, their testimonies are reminders that we are all just part of a continuum of investigation that extends back through the Enlightenment to Ibn al-Haytham, Aryabhata, and Aristotle, human links in centuries-long chains of questions.
Both writers exemplify the humanity of science: Seager and Johnson laugh, grieve, hope, fail, try, fail and try again. “We started from almost nothing,” Johnson writes about Mars, though she could be talking about pretty much every human endeavor. “We’ve gone careening down blind alleys and taken countless wrong turns, yet somehow, miraculously, the passion, ingenuity and persistence we have brought to the enterprise have moved us toward a truer understanding of another world.”
Why keep searching for life elsewhere when we sometimes seem to have a hard time appreciating it in our own backyard? What does it say about us?
“It says we’re curious,” Seager writes. “It says we’re hopeful. It says we’re capable of wonder and wonderful things.”
However fleeting our individual lives might be, it’s comforting to imagine that we Earthlings might not be utterly alone in the immensity of time and space. Do the math. Life may be more resilient and pervasive than we think. How lucky we are to be here long enough to appreciate that.