TRY TO IMAGINE, as you sit reading this, that you and everything around you are turning and circling and looping through space at speeds ranging up to 558,000 miles per hour. Or try to imagine space being curved or filled with particles that somehow behave like waves. Since Copernicus, the point is, physics has been awfully difficult to get our minds around. That's why it is so tough to know what to make of British physicist Julian Barbour's argument about time.

In his new book, The End of Time: The Next Revolution in Physics, Barbour asserts that time simply doesn't exist. This by itself is not so shocking. My friend Artie, for example, has always insisted that there's only change, not time. Things move around; time may just be a way of noting that. But Barbour goes further. He says there's no such thing as motion either. Instead, Barbour sees a universe filled with static instants -- instants that contain "records" that fool any conscious beings who happen to find themselves encased in one into believing that things have moved and time has passed.

Barbour's theory meets one test of important new ways of looking at the universe: It doesn't, on the face of it, make a lot of sense. That puts it right up there with relativity (Space is curved?), quantum mechanics (Particles are waves?) and Copernicus's ideas (The earth, despite all indications to the contrary, moves?). In fact, Barbour's assertion that the instants we experience do not follow each other in a temporal sequence seems as likely to elicit a "Go on!" as any theory physicists have dreamt up in the past half millennium. The question is whether his theory meets the other test of important new ways of looking at the universe: Is it, in other words, remotely possible that he is right?

There are two ways of determining that, given the absence, to date, of experimental evidence: first, by grappling with the theory itself or, second, by figuring out whether this guy seems worth trusting. Neither, in this case, is easy. Barbour's thinking is complex and his credentials eccentric.

Just what time is has always been difficult to figure. "Time is the biggest mystery," states the physicist Brian Greene, who leads an accessible and fascinating expedition through contemporary physics in his recent book, The Elegant Universe. Our sense -- and this might be called the Newtonian view -- is that a kind of perfect, invisible celestial clock, invariable and indefatigable, is ticking away somewhere out there. Sundials, Swatch watches, and the human aging process each, in its less-than-perfect way, reflects this absolute time. It seems as inescapable and inevitable as death -- its enforcer.

This common-sense view was one of many forever altered by Einstein's theories. We see time this way, he made clear, only because we move so slowly. If you could peddle your bicycle at something almost in the neighborhood of the speed of light, relative to an observer, your watch and your aging process would appear -- to that observer -- to slow. (From your own perspective, time, unfortunately, would still keep chugging along at its usual dispiriting pace, which makes it unlikely that anyone will figure out how to turn this phenomenon into a wrinkle cream.)

Relativity found time a home as one of the four dimensions in something called "spacetime." But it hardly settled the question of what time is. And the idea that time slows down in certain circumstances made it easier to imagine that time was just a construct of us observers, not itself a fact of nature. Plenty of space was left for time cynics like my buddy Artie and, of course, Julian Barbour.

BARBOUR, who lives near Oxford in England, is one of the only living physicists you will read, or read about, nowadays who is not in the employ of a college or university. In fact, Barbour, while he does have a Ph.D. in physics (earned in Cologne), has never taught physics. He calls himself "an independent." Barbour supported his family for decades by translating Russian scientific publications. His physics was done in his free time, at his own pace. Since Barbour's ideas have not been blessed by a tenure committee, and are radical, "people might naturally question," as one physicist puts it, "whether he is a crackpot."

There is considerable evidence to the contrary. Barbour's book, to begin with, is published by Oxford University Press. (As an Oxford author myself, I see this as clear proof of the book's merit.) Barbour has published, sometimes in collaboration with a genuine academic, some influential papers. He gets invited to important conferences. The back of his book is graced by an impressive collection of blurbs, including one from John A. Wheeler, one of the most accomplished physicists of the second half of the twentieth century. And then there is the enthusiastic (if difficult to follow) review his book received in the New York Times ("a masterpiece"), not to mention the designation bestowed upon it in one of many respectful articles in the London broadsheets: "much talked about."

The book itself describes a personal, spirited, sometimes stubborn, and mostly lonely intellectual quest. This gives it a slightly moist feel, as if we'd been invited directly into one man's cerebral cortex. But Barbour fulfills his main task -- explaining -- with industry and cleverness.

Not many physicists, including Barbour's respectful blurb writers, seem convinced that he is right about time. "Julian and I are very happy to disagree," is how the matter is worded, with respect and affection, by Fay Dowker, a physicist at Queen Mary and Westfield College, University of London. Still, most who are familiar with his work believe, as that physicist who mentioned the term certainly does, that, very far from being a "crackpot," Barbour is "an interesting, delightfully unusual, guy," who gets his math right and understands the equations in question. "Although his work is not widely known by the high-energy community in general," Dowker explains, "among a small, diverse group of physicists it is seen as challenging and interesting."

And these physicists are hesitant to simply dismiss his radical ideas. After all, physics was transformed early in the twentieth century by a set of radical ideas emanating from a fellow who also was not employed, during many of his most productive years, by a university.

BARBOUR STARTS WITH THE NOTION that time is just a way of describing change. "If you try to measure time," he told me in a recent telephone interview, "you have to have something that moves. It is remarkable how many people haven't considered this, including even Einstein, who never thought seriously about what a clock is." (Artie will enjoy learning that he may have been a step ahead of Einstein on this one.)

Without clock hands moving (or digital numbers flashing), without any motion, Barbour is convinced, there would be no time. Then he tries to prove -- more tentatively -- that there is no such thing as motion.

What if, Barbour wonders, we just imagine a kingfisher to be flying? After all, it isn't exactly the same bird at perch A and perch B: Its molecules constantly change; its atoms constantly change. What if our brain has captured a few snapshots of kingfisher-in-flight that it plays -- movie-like -- in such a way that we think we see continuous motion? What if the instants we inhabit somehow happen to be filled with "records" -- images of kingfishers with their wings spread, tread marks, "memories," fossils -- that manage to delude us into thinking that birds fly, cars lurch, species become extinct; "records" that manage to delude us into thinking that we are scurrying along some sort of path from the past to the future? Isn't it true that all we know now about the past or the future comes from thoughts or objects we experience now -- in the present?

What if, Barbour then asks, we're always trapped in one moment or another and everything else -- your sense, for example that X number of minutes ago you moved your hand and clicked on FEED -- is a kind of illusion, somehow evoked by the structure of this particular, all-encompassing moment? What if, in other words, our whole sense that things move is an illusion, as -- in another context -- our sense that the earth does not move proved to be an illusion?

For Barbour, what exists is not a universe moving through time; what exists is an endless, timeless series of possible configurations of everything in the universe -- each just an instant wide. There are configurations in which we each are born, presumably configurations in which we each die, and configurations in which we read articles about weird new theories. All these many, many possible instants are sitting in a "configuration space," which Barbour dubs (with a nod to another fellow who thought we were often deluded by appearances) "Platonia." These instants -- these "nows" -- are all there, like words in a book, at once. We experience many, many such instants -- and not necessarily in chronological order.

"I'm not a solipsist," Barbour insists, reassuringly. "I'm convinced that you're there. Equally I conclude that something I can call 'myself' is in other instants of time -- all the ones I remember from my past." Nevertheless, for Barbour possible instants -- a huge number of them, some containing him or us, some not -- are collected like cards in a deck. And it is not clear what instant might be dealt next (though the word "dealt" is probably too active and "next" too time-dependent for Barbour's theory).

This is, if it helps any, quite similar to the view of time presented in Kurt Vonnegut's 1969 novel Slaughterhouse Five, which Barbour has not yet read. ("I know," he says. "People keep telling me I should look at it.") Vonnegut describes most earthlings as trapped in moments like "bugs in amber." Billy Pilgrim, the book's main character, however, repeatedly comes "unstuck in time": He jumps, in no particular order (though in accordance with the needs of Vonnegut's narrative), from one point in his life to another. Moreover, on the planet Tralfamadore, which Pilgrim visits, "all time" is visible at once, as we "might see a stretch of the Rocky Mountains. It does not change. It simply is." That Rocky Mountain-like view of all time is remarkably similar to Barbour's Platonia.