[IP] From a Physicist and New Nobel Winner, Some Food for Thought
From a Physicist and New Nobel Winner, Some Food for Thought
October 19, 2004
By DENNIS OVERBYE
GOLETA, Calif. - Fresh from a new Nobel Prize, with a smile
as wide as the Pacific Ocean only a Frisbee throw away, Dr.
David Gross stood with a microphone on a stage at the Kavli
Institute for Theoretical Physics here.
"The most important product of knowledge is ignorance," he
declared. And without much more ado than that, Dr. Gross
proceeded to enumerate what he considered to be the most
enticing items that physics had learned enough to be
ignorant about in 25 different areas.
If there are any limits of the ambitions of physicists to
probe and quantify every last aspect of the world, they are
not to be found here. The questions, culled from hundreds
of e-mail messages from physicists around the world in the
wee hours of the morning, show how physicists' ambitions
have expanded. No longer content to examine the origin of
the universe, they are injecting themselves into the search
for the origin of consciousness and other life science
issues; not content to muse about building quantum
computers, they are thinking of training computers
themselves to be physicists.
The occasion was a three-day conference this month modestly
titled "The Future of Physics" that had been planned as a
double celebration, but turned into a triple one. It was
both the 25th anniversary of the institute, which was
founded by the National Science Foundation on the
University of California at Santa Barbara campus here in
1979, and the dedication of a new wing, designed by the
architect Michael Graves, complete with a portholed lounge
on the second floor looking out to sea.
The center, named three years ago for Fred Kavli, an
inventor and businessman who has become a financial angel
of physics.
On Oct. 5, the day before some 150 physicists were to
arrive, Dr. Gross, the director of the institute, was named
one of three winners of this year's Nobel Prize in Physics,
along with Dr. Frank Wilczek of the Massachusetts Institute
of Technology and Dr. H. David Politzer of the California
Institute of Technology, for helping explain the force that
holds atomic nuclei together and pens quarks together
inside protons and neutrons, where they cannot be seen.
As a result, the strawberries and whipped cream heaped in
bowls on the seaside lawn seemed especially sweet.
"Let's take this house of science on a ride through the
stars to solve some of humanity's most fundamental
questions," Mr. Kavli said at the dedication.
Dr. Gross had enlisted an all-star cast of physicists,
including Dr. Wilczek and six other Nobelists, to discourse
on what the last 25 years in physics had wrought and the
next 25 might bring.
As reflected in the talks here, the history of physics as
well as the history of the institute in the last quarter
century, is, like the universe, a story of expansion
outward from fundamental forces and particles, like gravity
and electrons, to the behavior of larger and larger
agglomerations of matter, complex systems, the weird
quantum properties of materials chilled to near absolute
zero, subject to huge pressures or magnetic fields, to
planets, stars and even life itself. Physicists who went
into biology once were content to apply their methods and
training to answering the questions raised by biologists,
noted Dr. William Bialek of Princeton, but now physicists
were asking their own questions about living systems,
searching for universal principles underlying the
activities at different levels of life.
In assembling his list, Dr. Gross was joining distinguished
company. In 1900 the mathematician David Hilbert published
a list of 23 important problems that has formed a research
agenda ever since. At the millennium four years ago, Dr.
Gross, and two other physicists, Dr. Michael Duff of the
University of Michigan and Dr. Edward Witten of the
Institute for Advanced Study inPrinceton, N.J., assembled a
list of 10 questions in particle physics and cosmology.
Some of Dr. Gross's questions are ripped from the
headlines. What is the dark matter that enfolds the visible
galaxies? What is the dark energy that seems to be
accelerating the expansion of the universe? Was there a
time before the Big Bang that started the universe, or is
time itself an "emergent concept" deriving from something
more fundamental that we don't know yet? Can physicists
make room-temperature superconductors?
Others reach into less publicized fields in an effort to
tap into uncharted controversies of the future. Here is a
sampler. Dr. Gross's talk is online at
online.itp.ucsb.edu/online /kitp25/gross/.
Can we measure the onset of consciousness in an infant?
"I love this one," said Dr. Gross, who speculated that such
an event was what physicists call a "phase transition,"
like the sudden melting of ice into water, when some
microscopic change causes a large-scale change in behavior.
"At some point it turns on," he said. Putting the emphasis
on measuring this, Dr. Gross explained, meant that
physicists would first have to define precisely what
consciousness was.
Can the theory of evolution be made quantitative and
predictable?
Given what we know about the genetic code and about
organisms, is it possible to do experiments on real
organisms and make quantitative predictions? In particular,
Dr. Gross asked, "Can one tell the shape of an organism by
its genome?" This, he mused, to much laughter, could be
homework in biology classes: give out a chart of the genome
and have the student "draw the picture."
Is quantum mechanics the ultimate description of nature?
It is amazing Dr. Gross noted, that 80 years after the
theory was formulated physicists and philosophers are still
debating the meaning of the paradoxical rules that govern
atomic behavior and underlie all modern technology. They
include such infuriating features as the uncertainty
principle, which ascribes a certain randomness to atomic
events.
"I see no evidence that anything is wrong with quantum
mechanics," Dr. Gross said to a ripple of laughter, but, he
added, physics should explore the possibility that it would
break down at short distances where gravity becomes
important, or in large complex systems, or as a description
of the universe itself.
Can we use astronomical observations to determine the
geometry of space-time around a black hole?
Einstein's general theory of relativity, which explains
gravity as the warped geometry of space-time, is the
mathematical language of cosmology, but is it really
correct? The theory has never been experimentally tested in
the really strong gravitational fields that prevail in a
black hole, the gravitational abysses that according to
Einstein can stop time and swallow everything, even light.
"Right now we have no data," Dr. Gross said. But many
physicists hope that they will eventually be able to
diagnose the space-time structures of black holes by
studying the roiling and rippling of space-time, so-called
gravitational waves, from the collisions of black holes, or
by following the motions of individual stars caught in that
fatal black grip, and thus find out if Einstein's theory is
right.
Modern particle physics, despite its success as exemplified
by his own Nobel, is awash in mystery, Dr. Gross said. For
example, physicists have yet to come up with satisfactory
equations to describe quantum chromodynamics, the theory of
the strong force.
Nor can physicists explain in any quantitative detail why
the universe consists of matter and not antimatter, its
bad-twin opposite. Neither question can be answered by the
present reigning theory, a suite of equations, known as the
Standard Model, he said. Rather it has whetted physicists'
desires for a grander more encompassing theory.
Is there low-energy supersymmetry?
Nearly every scheme
that seeks to unify the forces of nature into a single
equation relies in part on this concept. It posits a
relationship between the particles known as fermions that
comprise matter and the particles known as bosons that
comprise forces like electromagnetism or the strong force.
If it is true, all of the known elementary particles have
partners, as yet undiscovered, but which might constitute
the dark matter in the universe.
But there is as yet no scintilla of evidence in favor of
supersymmetry. Does it exist at the low energies available
to human experimentation? "The whole field hangs on the
answer," said Dr. Gross, who added that it was the "undying
hope" of physicists that supersymmetric particles would be
discovered when the Large Hadron Collider, to be the
world's largest, most energetic particle accelerator,
starts operating in 2007 at CERN, the European research
consortium in Geneva.
Is physics an environmental science?
This is one of the
more philosophical and contentious questions facing modern
physics. Is it possible, Dr. Gross explained, to calculate
all the parameters characterizing nature, like the ratios
of masses of elementary particles or the strengths of the
fundamental forces, from whatever the final theory turns
out to be? Or are some things simply accidents of history
or random quantum mechanical events?
Einstein proclaimed a theory that left God "no choice" in
such matters as the goal of physics, but, as Dr. Gross
acknowledged, recent results from string theory, the
putative theory of everything, and cosmological
speculations about the Big Bang, produce a "landscape" of
gazillions of possible universes, each with different
properties determined basically by chance. Our own universe
has the features it has, some theorists go on to suggest,
because those are the conditions under which life could
evolve. We live where we can live goes the argument, but
Dr. Gross admits that he hates it.
"I hate to give up this ambitious goal," he said, referring
to the Einsteinian dream of being able to predict
everything. He added that it was "kind of fun" being a
conservative.
Can we understand big things by understanding little
things?
After all, big things, no matter how complicated, are made
of little things. Physics has been guided since the time of
the Greeks by the assumption, known as reductionism, that
the world can be understood by breaking it down into tinier
parts, a few elementary particles interacting through four
basic forces.
But, Dr. Gross, a card-carrying reductionist, asked of the
reductionist principle, "Is this anymore obviously true
than was the idea that nature can't tell the difference
between the left hand and the right hand?" He was alluding
to surprising experiments at Brookhaven National Laboratory
in the 1950's showing in fact that nature did know the
difference between left and right when it came to the
"weak" force that causes some kinds of radioactivity.
Could physicists be so wrong again? "Who knows?" Dr. Gross
said.
When will computers become creative theoretical physicists?
And how will we train them?
Dr. Gross attributed this question to his fellow Nobelist
and former student, Dr. Wilczek. While others have
suggested that computers will eventually take over, the
issue of how to teach them was novel. In keeping with his
job nurturing theorists Dr. Gross added, "And that's really
fun to think about."
Will physics still continue to be important?
This, Dr.
Gross admitted, was the 26th question, but he allowed
himself to go over his own limit, he said, because this one
had an answer.
"Yes," he said.
http://www.nytimes.com/2004/10/19/science/19phys.html?
ex=1099201672&ei=1&en=0703c1838d7a31fb
-------------------------------------
You are subscribed as roessler@xxxxxxxxxxxxxxxxxx
To manage your subscription, go to
http://v2.listbox.com/member/?listname=ip
Archives at: http://www.interesting-people.org/archives/interesting-people/