Out There : LONELY HEARTS OF THE COSMOS <i> By Dennis Overbye</i> . <i> (HarperCollins: $25; 414 pp.</i> )

Cosmologists are physicists and astronomers who study the universe as a thing in its own right. They ask childlike questions. They want to know what the sky is made of (they don’t know yet). They want to know how time was born and how it will die. Dennis Overbye’s “Lonely Hearts of the Cosmos” is an eyewitness account of the last decade in cosmology--a grand era, for cosmology has blossomed into one of the most important sciences of our time, even if it’s a perfectly useless science.

Being a cosmologist is a peculiar way to make a living. You are paid to pose questions like “What’s the shape of the universe? Indeed, what is the universe? What’s it made of?” (Mostly not of stars and galaxies, but of the so-called Dark Matter, which nobody understands.) “Are there other universes? Could you create one in a laboratory?” Some cosmologists think you might be able to create a universe if you crushed 25 pounds of matter into a pinpoint much smaller than a proton, as Overbye explains. (That raises the question as to whether our universe is someone’s laboratory experiment.)

Cosmologists do a lot of deep thinking, and they look at the night sky with giant telescopes, trying to discern clues in the hundreds of millions of galaxies that cluster to form bubbles and veils across the face of the deep.

The characters who walk the immense stage of “Lonely Hearts of the Cosmos” are wonderful. We meet David Schramm, a former national-champion wrestler who once wondered if he should study the universe or become a wrestling coach. He chose the universe, not without regrets.

There’s Vera Rubin, who saw traces of the Dark Matter while she studied the light of galaxies, but who frequently was disbelieved because she was a woman. (Dissecting the universe was until recently thought to be a man’s work.)

There’s Alex Szalay, a Hungarian cosmologist who couldn’t make a living at the universe so he joined a rock band. (What else can a poor cosmologist do?)

We meet Stephen Hawking in a wheelchair. Hawking, his body and voice paralyzed by a degenerative nerve disease, has a voice synthesizer attached to his wheelchair. His voice box speaks with a faintly Russian accent while it delivers Hawking’s opinions on black holes. We learn that Hawking, despite his small size--he weighs no more than a child--is an immensely powerful figure and is not above being ruthless with certain colleagues.

Author Overbye (his name rhymes with “To be or not to be”) seems determined to break the formulaic pattern of science writing. For the most part, science writing is suffocatingly conventional in a literary sense. Most of it tends toward the “gee-whiz” school of science journalism, where the author gets up on a podium and lectures the reader in his own voice (often pedantic) on “fascinating” discoveries. The writing plods on for chapter after chapter, until you want to take the thing back to your bookstore and cry, “Refund!” Science journalism seems to be the last form of nonfiction in which the lessons of New Journalism have not been applied.

In this kind of writing, the author presents living persons to the reader and lets them do the talking, so that the reader meets a multitude of characters, hears a variety of voices. One has a sense of the full texture of life. As in a novel, no detail of human life is beneath notice. The New Journalism (not so new any more) has finally begun to percolate into science writing. Overbye lived among the cosmologists the way Jane Goodall lived among the chimpanzees. The cosmologists were studying the universe while Overbye was studying them, with a notebook and a tape recorder.

The central character in Overbye’s book is Allan Sandage, a giant among astronomers and a good choice for a protagonist since his life spans the history of modern cosmology, and because he is one of the most important players in that history. The story begins with Sandage as a young man, in 1954, having recently received the mantle of cosmology from Edwin Hubble, the great Mount Wilson astronomer who had died of a heart attack. Hubble had discovered that the galaxies are receding from each other like shreds of an explosion; that the universe, in other words, is expanding.

The dying Hubble more or less told the young astronomer that he would solve the riddle of the curvature of space and time. “What (Sandage) wanted to know,” as Overbye puts it, “was the distance to eternity.”

For the next four decades, Sandage tries to find the so-called Hubble constant, a number that will tell us how big the universe is, how old it is, what shape it has and how it will end--that is, the distance to eternity. Sandage is eager to assault the sky with the 200-inch Hale Telescope on Palomar Mountain, near San Diego. He takes photographs of galaxies on huge glass plates; the galaxies sprinkle the glass like dust. He thinks his plates are like “the plates of Moses,” holding the laws of space and time, if only Sandage can read them.

The book ends with Sandage in his 60s, now a withdrawn, harsh, amusing, secretive, deeply bitter, deeply religious man who has announced that he will never set foot on Palomar again. Moses has given up going to the mountain.

This is a moving portrait of a great scientist. He is wounded and unhappy after his tangles with the universe and, worse for him, his tangles with people. Space-time turned out to be a more complicated place than Sandage expected.

Most science books show the progress of science as a step-by-step revelation of truth, tending toward some final understanding. “Lonely Hearts of the Cosmos” does just the opposite. As the book unfolds, the universe becomes more mysterious. One gets the feeling that this is how science really operates.

Sandage is frustrated with the universe, with his colleagues, with himself. “Where did I go wrong again?” he mutters, staring at his data, convinced that he has found the Hubble constant but shocked and hurt that a younger generation of astronomers has grown up to attack his work.

Sandage calls astronomy an impossible science, because all an astronomer can do is look, and the galaxies are only faint smudges of light. “It’s a wonder we know anything at all,” he says, bemused.

Sandage is the deepest puzzle of all. He’s genial, witty, humble, prideful, dreadfully sarcastic, awed at the loveliness of the sky, mercurial, brilliant, angry, and thoroughly magnificent, as he tells Overbye about his life’s work. That Overbye persuaded Sandage to talk to him is a neat piece of reporting in itself.

The people in Overbye’s book are altogether too human, and yet they also are gigantic figures in the history of science. They dare to confront the simplest and perhaps the toughest question: What exactly is this thing we call the universe?

Their heroism is that of fallible human beings trying to make sense of the unknown.

* BOOKMARK

For an excerpt from “Lonely Hearts of the Cosmos,” see the Opinion section, Page 4.