Saturn's vanishing rings, and other surprises
Death by Black Hole: And Other Cosmic Quandaries
By Neil deGrasse Tyson
Norton, 320 pp., illustrated, $24.95
Several years ago I was lucky enough to visit the W. M. Keck Observatory, on Mauna Kea, Hawaii, almost 14,000 feet above sea level. In my ignorance I expected to walk through the door and find clusters of astronomers in white lab coats, banks of cool-looking computer monitors, and maybe even a few wizened Copernicus-types taking turns peering through the eyepiece of a massive telescope, speculating on the motions of the spheres.
Instead, a mild-mannered optics technician in jeans and white sneakers showed me his portable oxygen unit. He offered me coffee in a Styrofoam cup. He showed me a photo of his family. There were maybe a dozen people in the entire facility, which smelled vaguely of scrambled eggs, and the twin domes, beneath which gigantic, honeycombed mirrors sat reflecting the ceiling, were flat and motionless. The researchers, it turned out, made most of their observations remotely, in the town of Waimea , wearing shorts and flip-flops.
No long beards? No white coats? No Galilean telescope thrusting its nose up through the roof?
Nope. Modern astrophysics, it turns out, is built mostly on the analysis of spectra of light, much of which is entirely invisible to the naked eye. The universe throbs with the kinds of electromagnetic radiation we need specialized instruments to detect; radio waves radiate from nebulae, X-rays leave dying stars, and microwaves pour out of the chemical forges of the Milky Way.
We've known since the 1920s that the universe is expanding. Now we know it is accelerating, too. We've known for a few dozen years that heavy elements (including every element in our bodies) are born in the explosions of high-mass stars called supernovae.
But how did we learn these things?
The media rarely explains. That's at least partially because it's hard to explain, and partially because the methods are not sexy.
The dazzling images that come from the Hubble Space Telescope are definitely sexy. They can leave you breathless at the vastness and complexity of the universe. But astrophysicists aren't looking at beautiful images all day. Most of them are analyzing spectra. And studying invisible radiation flying to Earth from intergalactic space involves multiple levels of abstraction. An astrophysicist takes images of light coming from, say, a star. Then she makes spectra from that light, studies interference patterns in the spectra, and look for shifts in those patterns over space and time. Are you yawning yet?
Enter Neil deGrasse Tyson. Tyson is the director of the Hayden Planetarium at the American Museum of Natural History , in New York, and the host of a PBS television show called "Nova Science Now." He's telegenic, funny, and was once chosen by People magazine as the sexiest astrophysicist alive. He's also a very good writer.
Ever wonder what it would feel like to pass through the sun? Dig the proverbial hole to China and plummet toward the center of the earth? Get too close to a black hole? Witness the impending collision of the Milky Way and Andromeda galaxies?
Tyson elucidates these and dozens of other strange hypotheticals in his newest book, "Death by Black Hole: And Other Cosmic Quandaries." But this is not a book about science-fiction predicaments as much as an assessment of our current understanding of the universe.
What do we know? What are the gaps in what we know? And, most important , how have we come to know what we know?
The sun, it turns out, isn't yellow. The earth isn't a perfect sphere. Asteroids can and do have moons. Saturn will soon (in 100 million years, anyway) be shorn of its rings. The equinoxes do not consist of exactly 12 hours of daylight and 12 hours of darkness. Intergalactic space is so empty of matter that a random cube of it, "200,000 kilometers on a side, contains about the same number of atoms as the air that fills the usable volume of your refrigerator."
Tyson never neglects history, and as such he offers a wonderfully informed viewpoint on the slowly expanding boundaries of human knowledge, something he calls our "perimeter of ignorance." It is in these sections that he does his best work, allowing his reader to see how, through Newton, through Galileo, through the discoveries of the various bands of the electromagnetic spectrum, we have arrived at present-day understandings.
But he also does not forget that the universe still harbors plenty of secrets. "Astrophysics," he writes, "reigns as the most humbling of scientific disciplines. The astounding breadth and depth of the universe deflates our egos daily, and we are continually at the mercy of uncontrolled forces." Dark energy, dark matter, the failures of string theory, the origins of life -- Tyson happily admits that plenty of mysteries await exploration.
Insight is cumulative. Science builds itself on foundations laid and tested by preceding generations. Since Aristotle, since Newton, since Einstein, we've always needed writers who can explicate scientific discoveries to a broader audience. And as 21st-century scientists extend the envelope still wider, as we look to put telescopes farther from Earth and sink neutrino detectors deeper into Antarctic ice, it's more imperative than ever that we find writers who can explain not only what we're discovering, but how we're discovering it.
Neil deGrasse Tyson is one of those writers. "Death by Black Hole" is a terrific book.
Anthony Doerr is the author of "The Shell Collector" and "About Grace." 
