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7/14/06

Déjà Vu & Physicist Julian Barbour

Déjà Vu & Physicist Julian Barbour

An old woman sits in her wheel chair in a nursing home, a photo album recently on her lap. She has given it to another old lady to show pictures of herself with her first beau on the village green, of herself in bridal gown, of her child sitting on her knee. She looks up at the bare walls, and sees somewhere herself at sixteen, turning many heads, her father carefully screening suitors at the door. It all happened so fast, first that and now this. She opens the album to a new page to show her husband in the year before he died, proudly washing their new Ford in the driveway.

Consume my heart away, sick with desire and fastened to a dying animal. (W.B. Yeats)

In Julian Barbour's world, every first date, every kiss, every senior prom, every marriage, every departing is repeated precisely and endlessly. Every hot dog at a baseball game will be eaten again and again. A teenager's coolness lasts forever. Couples meet and fall in love for the first time and their love never dies. They grow old together or become divorced. Or one watches the other become sick and waste into death. Gew gaws hanging from their crib, as infants they awaken to the bright world and it starts over. Sometimes during the night as middle aged men and women, they dimly recollect something, but life presses them forward and they forget.

It has all happened millions of times before, Earth, the cosmos, hot dogs, the World Series, Caesar's conquests, everything. Nothing changes. Time and motion are illusions, according to Julian Barbour.

Before dismissing Barbour, consider that common sense doesn't tell you that without Earth gravity you would hurtle off into space. It doesn't tell you that passing through your body each second are 400 trillion neutrinos, some left over from the Big Bang that created the universe.

Barbour understands the outrageousness of his ideas and has trouble accepting them himself. Still, reason has led him to his view. He believes that most theoretical physicists have ignored time.

His credentials are solid, and prominent physicists take him and his unconventional ideas seriously.

He lives in South Newington, twenty miles north of Oxford, and not far from the fields where little Alice Liddell played, the child who inspired Lewis Carroll's Alice in Wonderland. She will forever play there if Barbour is right. Today other children frolic in the fields.

The central problem in modern science is the disjuncture between the gravitational world, where we live, and the quantum mechanical world, with tiny particles. Barbour contends that the problem arises because physicists mistakenly take time as real for their purposes.

Time differs, depending on the level of observation. At the quantum level it ticks away as it does in our lives. At the larger level of relativity things aren't that easy. Einstein bent the universe into spacetime, a seamless fabric. Space and time curve around stars and planets, causing light to bend rather than travel straight. Time slows down or stops near black holes.

Barbour arrived at his proposal through an equation developed by Bryce DeWitt and John A. Wheeler which tried to join the two worlds, quantum mechanics and Einsteinian general relativity. Imagine a grain of sand, then imagine all the beaches on ours and other planets. The grain is the quantum world; the beaches, the gravitational. DeWitt and Wheeler used Schrödinger's equation as the basis for calculations. (Irwin Schrödinger of Schrödinger's Cat fame)

Because their approach allows that energy changes with time, which doesn't happen in the universe at large, Barbour eliminated time. Unlike atomic interaction, the universe has nothing to interact with except itself. Get rid of time, and the Wheeler-DeWitt equation becomes a means to merge quantum and cosmic realities.

The crux of Barbour's argument is that each, past, present, and future, exists separately everywhere and everywhen. Our universe isn't single nor does it pass through time. He calls the now the universe completely frozen like a snapshot. If in an instant we could look at our hemoglobins, we would see one hundred million million of these hemomolecules change, which means that every split second we are a different person. Or, think of a movie film. Each frame captures one possible now. Nothing moves within the frame but the reel gives the illusion of motion.

We are everywhere at once, inhabiting a huge, static, everlasting tableaux that includes the entire universe at any given moment. Call the tableaux Now Forever.

As he develops his position, perhaps Barbour would lead the illusioned people of Plato's cave into the light of reality. Each now never changes, is timeless. Each life, so to say, is still. Barbour calls this world of still lives, Platonia, after Plato, who argued that reality is composed of eternal and changeless forms. The shadows in Plato's analogy compose the illusory flux of time.

Barbour says only a madman would deny we don't change much from second to second, but still asks in what sense can we be said to move. Nothing really moves, he contends. Each of our separate nows contains information about our senses of identify, memories, hopes, and fears. They are like snapshots. We are part of the snapshots.

We are immortal. Of that Julian Barbour is convinced, although he acknowledges that we should still buy life insurance. His immortality implies that life exists alongside death, that we do not pass through time.

I am not sure how this would console the old woman in the nursing home. Her loneliness is palpable, her yearnings real. Yes, she would experience her youth and happiness again, but so, too, would the photo album reappear on her lap as she sits, gray, wrinkled, in the home.

While Barbour would bridge the disjuncture between the quantum and gravitational worlds, we must live with the transit of what we call time.

The old woman again opens the photo album, looks at herself as a young girl, skirt spread daintily on the village green. Her swain, she recalls, had taken the photo. Oh yes, what was his name? So handsome, so full of fun. At nineteen, he was killed in action at the Somme. What if she had married him? She closes the book as she hears the nurse with meal tray entering the hall to her room.

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