Terry Blanton posted this interesting article (though the topic isn't
new to us..<g>..) on a vort list;
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It's good to see this in the media even if it is a bit inaccurate.
From:
http://www.nytimes.com/library/national/science/020299sci-essay.html
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New York Times -- Science Times Columns
2/2/98
By MALCOLM W. BROWNE
No one can see it, hear it, smell it or touch it, and yet people seem
to have sensed its existence for nearly as long as there have been
written languages.
Twenty-three centuries ago Aristotle inferred its existence by
proclaiming that nature abhors a vacuum. In ancient Rome, the Stoics
believed in a universal medium they called the "pneuma." In medieval
times, thinkers called it the "plenum," and later, it went under the
name "ether."
This ethereal stuff, in somewhat modified form, survived even the
investigations of modern science, even though it seemed for many years
that Einstein had consigned ether to the trash heap of obsolete
notions. In its latest incarnation, ether has become a universal web
of "quantum fields."
This stuff is hard to define, but it is what you have when there is
nothing else. Theorists spend a lot of effort thinking about it.
In the 19th century, with the realization that light travels in waves,
many scientists believed that there had to be some universal medium,
the equivalent of an ocean of water, through which light waves could
travel even in the vacuum of space. This implied that
something -- the ether -- pervaded every nook and cranny of the
universe, including the empty space within atoms and between galaxies.
But the 19th century version of ether was flawed.
As the Earth moves through the universal ether, it was reasoned, there
should be a detectable difference between the speed of a light beam
aligned with the Earth's direction of motion and that of a
perpendicular beam, just as the speed of a swimmer on a river depends
on whether he is swimming with, against or across the current.
But a landmark experiment in 1887 by two Americans, Albert A.
Michelson and Edward W. Morley, failed to find any difference in the
speed of light caused by differences in direction through the ocean of
ether.
Then in 1905 came relativity theory and an entirely new way to look at
space. With the birth of relativity theory it became clear that there
was no need for ether as a propagating medium for light waves;
space-time itself -- the four-dimensional framework of the universe
postulated by relativity -- was the tableau across which all physical
effects could play, including the transmission of light.
The ether theory fell into disfavor with the advent of Einstein's
theory of relativity, and although ether survived as a word, its
connotation as a universal standard against which absolute motion
could be detected had to be abandoned.
But in the current issue of Physics Today, Dr. Frank Wilczek of the
Institute for Advanced Study in Princeton, N.J., writes that the ether
has undeservedly been given a bad name, when in fact, it
should be regarded as the direct ancestor of quantum fields.
"It was a logical succession," Dr. Wilczek said in an interview.
"Modern quantum field theory is a direct descendant of the ether."
In his article, he wrote that "there is a myth, repeated in many
popular presentations and textbooks, that Albert Einstein swept the
ether into the dustbin of history."
Actually, Dr. Wilczek wrote, the ether, "renamed and thinly disguised,
dominates the accepted laws of physics."
In this view of things, intangible quantum fields fill everything in
the universe, including the voids inside atoms and the immense space
between galaxies.
Every conceivable type of particle capable of
existence has its own universal field extending throughout the
universe, and when any point in the field is "excited" -- tweaked with
energy -- it creates the field's associated particle, say, an electron
or a quark.
In "The Cosmic Code," the late Dr. Heinz R. Pagels wrote that the
universe could be likened to a superposition of gigantic bed springs,
each one corresponding to a particular type of particle. In
places where the "bed springs" -- or fields -- are strong, particles
of matter materialize.
In Dr. Pagels's analogy, a quark bed spring and an electron bed
spring, although intermixed, do not interact directly with each other.
But both can interact with a third field -- say, an electromagnetic
field -- and all the associated particles of the three fields are thus
interconnected.
Similar mechanisms presumably connect all the other universal fields,
many of which have yet to be
discovered, perhaps with the help of powerful new particle
accelerators.
Dr. Pagels was a hard-headed physicist and no mystic, but some
nonscientists have seen in quantum field theory an updated version of
pantheism, which postulates the presence of a deity in all things.
But shorn of theological associations, the flourishing of 20th century
physics based on quantum electrodynamics has shown that even the
vacuum of space, utterly devoid of matter or conventional forms
of energy, actually seethes with activity.
For the sake of simplicity many physicists would like to believe that
the overall total energy of the universe is zero. But even if this is
so, there are constant brief and very tiny fluctuations that permit
the fleeting existence of virtual particles of all kinds.
If in some way a virtual particle can acquire energy from some outside
source it becomes a real particle; otherwise, it swiftly disappears.
This view of things is not only a logical consequence of quantum
electrodynamics; it has been demonstrated by many phenomena and
experiments. One experiment, easily understood even by nonscientists,
was first performed three years ago.
Among the components of the modern-day ether -- or, as most physicists
prefer to call it, the vacuum -- are virtual waves. In 1948, a Dutch
physicist, Hendrick B. G. Casimir, predicted that a pair of metal
plates held very close together in a vacuum would exclude any virtual
waves with wavelengths longer than the width of the gap between the
plates. There being fewer waves between the plates than in the normal
vacuum environment outside the plates, a small force from the outside
should push the plates together.
For nearly half a century no one got around to testing this
prediction, although physicists considered the outcome a foregone
conclusion. But in 1996, Dr. Steve K. Lamoreaux, then at the
University of Washington in Seattle built an exquisitely sensitive
apparatus containing two Casimir plates and a balance, and performed
the difficult experiment.
The attractive force he measured between the plates was within 5
percent of the force predicted by quantum electrodynamic theory -- a
tremendous success.
In November, two other physicists, Dr. Umar Mohideen and Anushree Roy
at the University of California at Riverside performed a more refined
version of the plate experiment, for which their result was within 1
percent of the value predicted by theory.
Other pieces of evidence for a universal vacuum packed full of unseen
ether -- or whatever it should be called -- have come from the cosmos.
Astrophysicists have long known that there is far too
little "visible matter" -- matter that can be detected directly -- to
account for the powerful gravitation of galaxies, galactic clusters
and other large-scale bodies.
The nature of the gravitating substance is unknown, but one thing is
clear: "Empty" space is anything but empty; the ether lives on.
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