Ceilidh

Michael Zey
futurist3000@aol.com

--------------------------------------------------------------------------------

Authors:                  Sharon Begley

Pagination:               B.1

ISSN:                     00999660

Subject Terms:            Research
                         TheoryPhysics
                         Cosmology

Classification Codes:     8306: Schools and educational services
                         5400: Research & development


Abstract:

POETS AND DREAMERS have long yearned to "see a world in a grain of sand,"
as William Blake put it, but physicists and cosmologists have an even grander
aspiration. As physicists try to identify and understand the most fundamental
building blocks of the material world, and as cosmologists explore how
the universe began, each group is finding some of the best clues in the
other guys' realm. This meeting of quarks and cosmos, says physicist Shamit
Kachru of Stanford University, Palo Alto, Calif., "is probably the most
exciting theme in physics and cosmology today."

In the latest convergence of large and small, scientists using NASA's orbiting
Chandra X-ray telescope confirmed this week that the universe is in the
grip of a mysterious "dark energy." Although scientists don't know what
dark energy is, they can measure what it does: It acts as a sort of antigravity
that makes the universe even friskier than thought. Instead of expanding
sedately from shortly after its moment of creation some 13 billion years
ago, the universe is accelerating ever faster thanks to dark energy.

A growing number of physicists think the hidden dimensions may be detectable
after all. "The additional dimensions of space-time," says physicist Eric
Linder of Lawrence Berkeley National Lab, Berkeley, Calif., "might give
rise to dark energy."
Copyright (c) 2004, Dow Jones & Company Inc. Reproduced with permission
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Full Text:

POETS AND DREAMERS have long yearned to "see a world in a grain of sand,"
as William Blake put it, but physicists and cosmologists have an even grander
aspiration. As physicists try to identify and understand the most fundamental
building blocks of the material world, and as cosmologists explore how
the universe began, each group is finding some of the best clues in the
other guys' realm. This meeting of quarks and cosmos, says physicist Shamit
Kachru of Stanford University, Palo Alto, Calif., "is probably the most
exciting theme in physics and cosmology today."

The quarks-and-cosmos approach has worked before. In 1973 a young physicist,
Edward Tryon, floated the audacious idea that behavior observed in the
subatomic world might have brought the universe into existence 13 billion
years ago. Quantum physics, which describes electrons and quarks and other
fundamental particles, had found that even in empty space, particles can
pop into existence, albeit fleetingly. What if, Prof. Tryon asked, the
universe sprang from just such a quantum fluctuation that, well, got out
of hand?

Perhaps, he wrote, our universe is just "one of those things that might
happen from time to time." His speculation became the basis for what is
now the leading theory (well supported by astronomical observations) of
how the universe was born and evolved.

In the latest convergence of large and small, scientists using NASA's orbiting
Chandra X-ray telescope confirmed this week that the universe is in the
grip of a mysterious "dark energy." Although scientists don't know what
dark energy is, they can measure what it does: It acts as a sort of antigravity
that makes the universe even friskier than thought. Instead of expanding
sedately from shortly after its moment of creation some 13 billion years
ago, the universe is accelerating ever faster thanks to dark energy.

As cosmologists rack their brains for where dark energy came from, some
are thinking small. Dark energy, they suggest, may leak out from the hidden
dimensions posited by the latest pet proposal from subatomic physics, string
theory.

STRING THEORY envisions the material world as made of infinitesimally small
strings, either loops or snippets. Like a violin string that can produce
different notes, these strings, too, emit different notes depending on
how they are excited. Each note is a different elementary particle, such
as a quark or an electron.

Not ones to let their imaginations stop there, string theorists posit that
there are unseen dimensions in space. Besides length, width and depth,
there are an extra six or seven, curled up so tightly they are undetectable.
It's like seeing a garden hose from far away. The hose seems to have only
length and width; its depth becomes visible only close up. Space, say string
theorists, might similarly harbor unseen dimensions, visible only on the
tiniest scale.

That claim, for a scientific theory, is like going around with a "kick
me" sign on your back -- it invites derision and abuse. Since it's hard
to imagine how such dimensions might be detected, critics dismiss string
theory as more untestable metaphysics than provable physics.

But a growing number of physicists think the hidden dimensions may be detectable
after all. "The additional dimensions of space-time," says physicist Eric
Linder of Lawrence Berkeley National Lab, Berkeley, Calif., "might give
rise to dark energy."

Going back to the garden hose, water pouring out of a flat strip of plastic
would seem utterly impossible. But if you saw a gusher, you would realize
that the hose is three-dimensional, not two. In much the same way, dark
energy gushing out of what seems to be three- dimensional space "might
be evidence of these additional dimensions," says cosmologist Michael Turner
of the National Science Foundation. Studying the dark energy more closely
might provide hard evidence of those hidden dimensions.

LAST WEEK, DURING a conference at the Stanford Linear Accelerator Center
in Palo Alto, physicist Richard Easther of Yale University, New Haven,
Conn., suggested another way to probe the cosmos for evidence of strings
and hidden dimensions.

Strings, he believes, might leave tiny ripples in the cosmic microwave
background. This radiation, which bathes the entire cosmos, is interpreted
as the fading whisper of the "big bang" in which space, time and the universe
were created. Strings, says Prof. Easther, might cause the observed hot
and cold spots in the radiation to deviate from expectations by 1% or so.

Studies of the universe might also test another odd prediction of string
theory. Matter comes in indivisible chunks, such as quarks and electrons.
As far as we know, there is no such thing as half a quark or one-third
of an electron. String theory says space, too, might be chunky. "You would
reach a point where space can't be sliced up any further," says Prof. Easther.

In that case, everything in the current cosmos arose from a space of finite-though-tiny
size back when the universe was in its infancy. "Some memory of this would
be maintained" in the structures and cosmic radiation we see today, says
Prof. Easther. Blake, it seems, was more right than he knew.