Over the eons, the few scattered islands radiated life as if each were its own planet. None of them was large enough to incubate large predators. Each pinprick of land was a sealed terrarium sporting enough species for a small Earth.
Dozens of dispersed intelligent species spoke millions of languages. Even the pidgins numbered in the hundreds. No town was bigger than a hamlet. Every few miles we came across a speaking thing whose shape and color and form were wholly new. The most universally useful adaptation seemed to be humility.
The two of us swam along veins of shallow reef down into underwater forests. We scrambled up onto islands whose complex communities were threaded into immense trading networks with islands far away. Caravans took years, even generations, to complete a deal.
No telescopes, Dad. No rocket ships. No computers. No radios .
“Only amazement.” It didn’t seem like an outrageous trade.
How many planets are like this one?
“There might be none. They might be everywhere.”
Well, we’ll never hear from any of them .
I WAS STILL DREAMING UP NEW LAYERS to our creation when I realized I didn’t need any more. I leaned in. Robin’s breath came light and slow. The stream of his consciousness had broadened to a miles-wide delta. I slipped off the bed and reached the doorway without a sound. But the click of the light switch jolted his body upright in the sudden dark. He screamed. I flipped the light back on.
We forgot Mom’s prayer. And they’re all dying .
We said it together: May all sentient beings be free from needless suffering.
But the boy who took the next two hours getting safe enough to fall back asleep was no longer sure if that prayer was doing much of anything.
THEY SHARE A LOT, ASTRONOMY AND CHILDHOOD. Both are voyages across huge distances. Both search for facts beyond their grasp. Both theorize wildly and let possibilities multiply without limits. Both are humbled every few weeks. Both operate out of ignorance. Both are mystified by time. Both are forever starting out.
For a dozen years, my job made me feel like a child. I sat behind the computer in my office looking at data sets from telescopes and toying with formulas that could describe them. I roamed the halls in search of minds who might want to come out and play. I lay in bed with a canary-yellow legal pad and a black fine liner, re-creating the journeys to Cygnus A or through the Large Magellanic Cloud or around the Tadpole Galaxy, trips I’d once made in pulp novels. This time around, none of the indigenous inhabitants spoke English or practiced telepathy or floated parasitically through the frozen vacuum or linked together in hive minds to enact their master plans. All they did was metabolize and respire. But in my infant discipline, that was magic enough.
I made worlds by the thousands. I simulated their surfaces and cores and living atmospheres. I surveyed the ratios of telltale gases that might accumulate, depending on a planet’s evolving inhabitants. I tweaked each simulation to match plausible metabolic scenarios, then incubated the parameters for hours on a supercomputer. Out popped Gaian melodies, unfolding in time. The result was a catalog of ecosystems and the biosignatures that would reveal them. When the space-borne telescope that all my models waited for launched at last, we’d already have spectral fingerprints on file to match to any imaginable perpetrator of the crime of life.
Some of my colleagues thought I was wasting my time. What’s the use of simulating so many worlds, many of which might not even exist? What’s the use of preparing targets beyond the ability of current instruments to detect? To which I always answered: What’s the use of childhood? I was sure that the Earthlike Planet Seeker that hundreds of colleagues and I lobbied for would come along before the end of the decade and seed my models with real data. And from those seeds, the wildest conclusions would grow.
Much of existence presents itself in one of three flavors: none, one, or infinite. One-offs were everywhere, at every step of the story. We knew of only one kind of life, arising once on one world, in one liquid medium, using one form of energy storage and one genetic code. But my worlds didn’t need to be like Earth. Their versions of life didn’t require surface water or Goldilocks zones or even carbon for their core element. I tried to free myself from bias and assume nothing, the way a child worked, as if our single instance proved the possibilities were endless.
I made hot planets with massive wet atmospheres where life lived in the plumes of aerosol geysers. I blanketed rogue planets under thick layers of greenhouse gases and filled them with creatures who survived by joining hydrogen and nitrogen into ammonia. I sank rock-dwelling endoliths in deep fissures and gave them carbon monoxide to metabolize. I made worlds of liquid methane where biofilms feasted on hydrogen sulfide that rained down in banquets from the toxic skies.
And all my simulated atmospheres waited for the day when the long-gestated, long-delayed space-borne telescopes would lift off and come online, blowing our little one-off Rare Earth wide open. That day would be for our species like the one when the eye doctor fitted my vain wife with her first pair of long-overdue glasses, ones that made her shout out loud with joy at being able to see her child from all the way across a room.
THE SHORT, HARD NIGHT made for a late morning. I didn’t get Robin to school until ten: another demerit for us both. When I got him there at last, the hardware on my cargo pants set off the security scanner. We had to go to the office to sign the tardy sheet. By the time Robin rejoined his smirking class, he was humiliated.
I rushed from his grade school to the university, where I parked illegally to save time and wound up getting a stiff ticket. I had forty minutes to prep my lecture on abiogenesis—the origin of life—for the undergraduate astrobiology survey. I’d taught the same course only two years before, but dozens of new discoveries since then made me want to start over.
In the auditorium, I felt the pleasure of competence and the warmth that only comes from sharing ideas. It always baffles me when my colleagues complain about teaching. Teaching is like photosynthesis: making food from air and light. It tilts the prospects for life a little. For me, the best class sessions are right up there with lying in the sun, listening to bluegrass, or swimming in a mountain stream.
Over the run of eighty minutes, I tried to convey to a coven of twenty-one-year-olds with a wide spectrum of intellectual abilities just how absurd it was for everything to spring up out of nothing. The alignment of favorable circumstances for the emergence of self-assembling molecules seemed astronomically unlikely. But the appearance of protocells almost as soon as the molten Hadean Earth cooled suggested that life was the inevitable by-product of ordinary chemistry.
“So the universe is either pregnant everywhere, or barren. If I could tell you which, beyond all doubt, would it change your study habits?”
That got a polite, Okay-Xer chuckle out of the happy few who were paying attention. But the rest had signed off. I was starting to lose them. It takes a certain kind of strangeness to hear the cosmic symphony and to realize that it was both playing and listening to itself.
“Here on Earth, it was archaea and bacteria and nothing but archaea and bacteria for two billion years. Then came something as mysterious as the origin of life itself. One day two billion years ago, instead of one microbe eating the other, one took the other inside its membrane and they went into business together.”
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