WHY DO WE EXIST?

From the Big Bang to big brains.

Scientists have discovered some 6,000 planets orbiting other stars. Most of them likely have atmospheres too thick or too thin to support life. So how did we get so lucky? According to astrophysicist Oluseyi, “The simple answer: a big-ass astronomical collision.” Some 4.5 billion years ago, a Mars-sized object slammed into proto-Earth, churning its molten core into a powerful dynamo, producing a magnetic field that shields the atmosphere, allowing it to stay right in the Goldilocks sweet spot: transparent enough to let sunlight through and not so dense as to boil the oceans. But even with ideal conditions in place, “Earth took an astounding 2.5 billion additional years to evolve multicellular organisms.” Which means life needs not only lucky breaks, but lots of time, too. To understand that, we must venture into other realms—nine of them to be exact. They include the Middle Realm and the Realm of Life, plus the Cosmological, Quantum, Temporal, Dark, and Multiverse Realms, the Realms Beyond Horizons and the Realm of Imagination. If these sound contrived, they are. “The Nine Realms are my Scientific Wild-Ass Guess—my SWAG—for organizing reality,” Oluseyi writes. But he offers exceedingly clear explanations of the science as he goes, from the origin of fusion in protostars to black holes to quantum tunneling. The wonderfully dizzying result is that it places us, viscerally, in the scheme of things. Energy flows through these nested realms, and there, in the middle, is us: knots of energy tying together the largest and smallest scales. For one molecule of carbon you need “a whole multigenerational family of deceased stars”; for one bacteria you need cosmic webs of dark matter. For a book that asks “Why?” the prose tends to skim the surface. This lightness grates at times, over-punctuated with exclamation marks and attempts at humor that don’t always land. (“You’ve probably heard the term ‘carbon dating’ before, but it’s not about carbon going out to dinner and hooking up.”) That said, some do. (“Pack up your cat. We’re headed to the Quantum Realm.”) And the pace, despite the density of science, is propulsive from start to finish.

A sweeping, lively tour of the cosmos that makes life feel like a miracle.