THE GIANT LEAP

Life launches into the unknown.

Some 3.7 billion years ago, life awoke on our rocky blue planet and, slowly but surely, oozed, swam, scuttled, and crawled into every ecological niche it could find. Eventually, it leapt right off the face of the Earth. Scharf, an astrobiologist and senior scientist at NASA, tells the awesome story of biology’s boldest migration—from the thinkers who cracked the mathematics of motion, mechanics, and gravity to the engineers who built spacecraft and robotic probes and solved the challenges of astro-navigation and communications. Now, citizens of more than 48 countries have ventured into orbit, not to mention chimpanzees, dogs, rabbits, wasps, tortoises, cockroaches, and jellyfish. Scharf casts this outward movement as an evolutionary imperative—the “expansion of living things into a narrow shell around the Earth and along a tiny thread of space to the Moon”—that will inevitably press onward to Mars, asteroids, and beyond, just by nature doing what it does. Consider, for example, that any water on the Moon may have been produced on Earth by photosynthetic organisms and scattered to the lunar soil by solar winds back when the Moon was closer. Through electrolysis, that water could be decomposed into hydrogen for fuel and oxygen for breathing. “If humans end up harvesting that water for the exploration of space,” Scharf writes, “it will be a case of life providing its own means to move beyond the confines of a single planet and its natural satellite.” This makes for a compelling narrative—but the thing about evolution is that we evolved to live here. Already in Low Earth Orbit, Scharf notes, astronauts aboard the International Space Station suffer “puffy head, bird legs syndrome,” scarring of the heart tissue and “space diarrhea,” and that’s just from the change in gravity. Far harsher conditions await us farther from home. Scharf may be right that “life’s relentless, mindless impetus to extend itself” will culminate in what he calls the Dispersal with a capital D. But as the fossil record shows, extending beyond your niche can also land you extinct. It was for good reason that Goldilocks, having found the bed that was just right, stayed there.

A deeply researched, expertly written account of the fascinating interplay between evolution and exploration.