“Greener Pastures,” the title of a recent Splice Today article, reminded me of that term’s use in the 1990s sci-fi show Babylon 5. Justin, a human working for the advanced species known as the Shadows, explains to Capt. John Sheridan, commander of the Babylon 5 station: “You see, John, back a million years ago, there were forces prowling around the galaxy beyond anything that we could understand. And, like anything else, most of them outgrew this little quadrant of the universe and headed off toward greener pastures.”
Two ancient races, the Shadows and the Vorlons, stayed as “shepherds” to younger ones like humanity. They espoused distinct philosophies; the Vorlons sought order, while the Shadows stirred up strife, which they saw as a spur to development. I wondered, though: What were the “greener pastures” to which other “old ones” had decamped? The show established only that such destinations were “beyond the rim” of our Milky Way galaxy. I remained curious as to what parts of the cosmos might be more attractive than our own.
Physicist Martin Rees has stated a broader perspective, noting our universe itself may not be optimal for life: “In other universes there may be an even richer potentiality for life and complexity.” If so, that undercuts an argument conservatives began making in the 1990s, that our universe’s congeniality to life is evidence of a cosmic designer, specifically God. This argument has many problems, including uncertainties about what kinds of life are possible under various cosmic constraints. Coupling the “fine-tuning” argument with a case against evolution makes little sense, moreover, as the noted life-friendly conditions are what allow evolution, while traditional creationism posits a hostile physical world.
It may be, though, that our planet isn’t all that good for life, compared to others in our own galaxy. Science journalist Natalie Wolchover discusses this in a New York Times column, on scientists’ interest in possible “‘superhabitable worlds,’ planets that would allow carbon-based life to persist longer and become even more complex and diverse than on Earth.” Such could be the case with “super-Earths,” some 20 to 30 percent bigger than our planet, orbiting a star at a distance that allows liquid water. The greater gravity of such worlds would enable thicker atmospheres, protecting life. Orbiting K-dwarf stars, which have long lifespans, would mean extra billions of years for evolution. Lab experiments indicate the orange light from such stars is compatible with photosynthesis.
Not everyone’s enthused by such possibilities. A sampling of reaction to Wolchover’s column on X and Bluesky included comments such as, “Why do we keep looking for another habitable planet? Wouldn’t it be easier to keep Earth habitable?” This is an inane objection to the science involved. Though Elon Musk and others have made (unrealistic) proposals for colonizing Mars or other parts of our solar system in coming decades, no one is making a case for relocation to a far-more-distant super-Earth, as it would take many centuries for spaceships to get to any such place, under optimistic assumptions.
These planetary considerations echo an old philosophical debate about the moral nature of the universe. In 1710, philosopher Gottfried Wilhelm Leibniz argued it’s the “best of all possible worlds,” reflecting creation by a benevolent, omnipotent God. “A lesser good is a kind of evil,” he wrote, and if there were no optimal world, “God would not have produced any.” We humans don’t see the big picture, Leibniz pointed out, including possible “blessed creatures” around other suns, and “it may be that all evils are almost nothingness in comparison with the good things which are in the universe.” Voltaire satirized this view via his character Dr. Pangloss, who sees earthquakes and other calamities as good.
Science has much to learn about the possibility of other planets that are more amenable to life, physically. Politically, I’d wager we’re one of the more screwed-up planets in the galaxy.
—Follow Kenneth Silber on Substack & Bluesky. He’s written for Splice Today since 2018.