It's rare that a person gets a chance to overturn humanity's conception
of the universe.
But with five scientific papers submitted in 1905, Albert Einstein
managed to do that three times: proving the existence of atoms,
uncloaking the bizarre realm of quantum mechanics and overturning
views of space and time.
Einstein overhauled much of physics at age 26
during a seven-year stint as a Swiss patent clerk, newly married
to his first wife and with a 1-year-old son. This year, in 2005,
physicists, authors, cooperative computing projects and even choreographers
are commemorating his achievement.
Einstein is best known to the general public
for his theory of relativity, the opening salvo of which came
in a paper submitted in June 1905. That theory ultimately created
a new conception of space, time and gravity. But the Nobel Prize
came for his first work of 1905, which helped lay the foundation
for quantum physics by suggesting that light behaves both like
a wave and as a particle.
"Relativity stretched our notions of space and time, but
we still had space and time. Quantum physics destroys our everyday
notions," said Richard Wolfson, a professor at Middlebury
College in Vermont, in a lecture marking the 100th anniversary
of Einstein's annus mirabilis.
And the shock waves spread widely: Decades later,
the quantum revolution Einstein helped begin has become a fact
of life in microprocessor design.
Einstein's papers that year are neatly packaged
resolutions to the physics problems of the day. He launched them
without the support—or hindrances—associated with
being a typical young university researcher.
"It's unlikely he could have come up with
relativity and quantum theory as a junior lecturer in a well-established
physics department, where such ideas would probably have been
suppressed as cranky coming from a man with no reputation,"
said Andrew Robinson, a scholar at Eton College and the author
and editor of "Einstein: A Hundred Years of Relativity."
To a certain extent, Einstein was in the right
field at the right time. Experiments to test new theories were
more affordable, and the field of physics was young enough to
accommodate generalists such as Einstein.
"The outstanding problems in physics now
are in some respects harder than the outstanding problems in physics
100 years ago," said Rice University physics professor Doug
Natelson. That doesn't mean Einstein had it easy, though. If Einstein
hadn't existed, he said, "I doubt it would have been one
individual who would have figured out all these things in such
a short space of time."
Quantum physics
Einstein's first paper, submitted in March, concerned quantum
physics, the peculiar realm of the ultra-tiny in which certainties
are replaced by fuzzy clouds of probability. Max Planck started
the quantum physics ball rolling in 1900, but Einstein gave it
major impetus when he showed that 19th-century physicists' view
of light as electromagnetic wave to be incomplete.
The word "quantum" refers to discrete
packets of light-particles now called photons. Einstein's work
helped show that light behaved both as particle and a wave.
Light's wavelike nature could be seen in phenomena
such as interference patterns that also appear with waves in water.
For example, with both light and water, peaks of two waves can
combine into a taller peak, or a trough of one wave can cancel
out the peak of another.
But some phenomena don't take well to the wave
description. One was the photoelectric effect, in which light
shining on metal causes it to emit electrons. Einstein's first
1905 paper relied on the quantum description of light to explain
how an increase in the light intensity caused more electrons to
be emitted—but not higher-energy electrons, as the wave
theory predicts.
"This was revolutionary. Neither classic
mechanics nor classical electromagnetic theory could survive in
the face of quantum phenomena," said John Stachel, editor
of "Einstein's Miraculous Year: Five Papers That Changed
the Face of Physics."
Quantum physics didn't even sit well with Einstein
himself. "No longer did tiny particles have a definite position
and speed . . . Einstein was horrified by this random, unpredictable
element in the basic laws and never fully accepted quantum mechanics,"
said Stephen Hawking, a cosmologist at the University of Cambridge
in England, in an essay in Robinson's book.
Molecules and atoms
The next two papers were easier for the physics community to swallow.
They validated the idea that matter was composed of atoms and
of groups of atoms called molecules.
Though most scientists accepted the concept,
there were significant holdouts. "At that time, there were
people who doubted the existence of molecules," Stachel said.
The first of these papers, a doctoral thesis
submitted in April, was Einstein's prediction that the size of
molecules could be gauged by the effects of dissolving sugar in
a liquid. Einstein argued that "the effect of the dissolution
of sugar molecules would change the viscosity of fluid; you can
measure the viscosity, and from that estimate the size of the
molecules," Stachel said. His prediction proved to be not
far from reality.
Second was a description of the mechanism underlying
Brownian motion—a particle's small random movements named
after botanist named Robert Brown who observed pollen grains jiggling
in water. Einstein derived a theory that predicted how far a particle
will move over time, given such buffeting—a theory that
was confirmed a few years later and which demonstrated that properties
such as temperature and pressure were reflections of the average
behavior of huge numbers of molecules.
Relativity
Einstein's final two 1905 papers concerned relativity, the mind-bending
idea about the ticking of clocks and the speed of light that most
people associate with Einstein.
In June came the first paper, describing special
relativity. In it, Einstein proposed a solution to a problem that
had plagued physicists concerned with the spread of light waves.
The prevailing belief was that light waves traveled in a fixed
medium called the ether, analogous to how water waves travel in
the medium of the ocean and sound waves travel in the medium of
the air.
Under that belief, the speed of light would vary
according to how fast an observer was traveling compared with
the ether. Physicists Albert Michelson and Edward Morley famously
failed to find that difference in an experiment to measure changes
in the speed of light as the Earth moved in different directions
compared with this theoretical ether.
Einstein's June paper simply did away with the
idea of the ether and said light moves at the same speed—about
186,000 miles per second—regardless of the speed of the
observer. The same beam of light will appear to be a different
color to two observers moving at different speeds, but the beam
will still be moving at the same speed compared with either of
them.
One consequence of this theory is that there
is no single universal clock ticking in lockstep across the entire
universe. Rather, time passes differently for different clocks
moving at different speeds.
In September, Einstein submitted a follow-up
paper that introduced another notion: Mass and energy are equivalent,
and a change in a particle's mass is associated with a change
in its energy. The paper didn't include the famed equation E=mc2,
but it laid the groundwork, Stachel said.
It wasn't until 1932, Stachel said, that physicists
observed that a tiny amount of mass disappeared in radioactive
decay—mass that was converted into the energy of emitted
gamma rays or beta particles. A more notable illustration came
at the end of World War II, when the mass lost from fissioning
atoms became the energy of the explosions over the Japanese cities
of Hiroshima and Nagasaki.
Einstein's relativity work wasn't done with the
debut of special relativity in 1905. A decade later, the broader
general relativity theory emerged, complete with its predictions
that gravity could bend the path of light through an effect astronomers
now call gravitational lensing.
Where Einstein's rubber hits the road
Einstein's work remade science, but most of its effects on today's
technology industry have been indirect.
"It's a stretch to talk about Einstein's
contributions to computing," said Tom Theis, director of
physical sciences for IBM's research group. But Einstein's work
has been relevant to the field, and more need to follow in his
footsteps, Theis said: "Continued support of basic research
is necessary to lay the foundations for tomorrow's technology."
Robert Chau, director of transistor research
and nanotechnology at Intel, deals with Einstein's legacy daily
as he tries to create ever-smaller transistors, the on-off switches
at the heart of microprocessors.
"It laid down the foundation for modern
physics, for what we do today for nanodevice study," Chau
said. Quantum mechanical constraints arrived in microprocessor
design in about 1990, when electron behavior called "tunneling"
began affecting the thinnest transistor components. This quantum
mechanical effect leads to wasted power and heating problems and
now is a dominant concern.
Einstein's 1905 papers did have some direct connections
to today's engineering work. One widely cited example is the Global
Positioning System, the navigation technology based on satellite
signals with precise timing information. The GPS satellites move
fast enough compared with the Earth's surface that relativistic
time changes must be taken into effect.
The photoelectric effect also is employed in
a technology called X-ray photoemission spectroscopy, which underlies
diagnostic tools in the microprocessor industry. "It lets
you characterize the interfaces between materials," for example
how electrons move between metals and semiconductors in chips,
said Rice's Natelson.
Einstein's theories were connected to experimental
reality, and physicists taking inspiration should follow that
strategy—especially proponents of today's string theory—said
Philip Anderson, a Princeton University physics professor whose
essay on Einstein appears in Robinson's book.
"In the half a century since his death,
the mystique surrounding Einstein has created a cult that in my
view starts clever physics students by the thousand off in the
entirely wrong direction," Anderson wrote. "The cult
makes Einstein into the embodiment of a 'pure' theorist, a genius
so brilliant that he snatches his ideas from thin air and achieves
revolutionary advances solely by the exercise of mathematical
reasoning."
Experiments to prove Einstein's theories are
still active. Today, physicists involved with the Laser Interferometer
Gravitational Wave Observatory (LIGO) project are trying to verify
the existence of gravity waves, which physicists agree is a consequence
of Einstein's general relativity theory. Einstein himself became
skeptical of the prediction and even tried to disprove it, Stachel
said.
It's a measure of the scientist that his ideas
are still at the forefront of physics. "In my opinion, he
was a true genius," Chau said, "well ahead of his time
and, in many aspects, beyond
modern days." |