Einstein the Realist

"Realita dan Bukan Realita adalah perspektif pikiran manusia itu sendiri, ini adalah semata-mata apa yang ditangkap oleh indrawi manusia belaka, karena yang ada akhirnya akan tiada"

~Arip~

By: Prof. David Deutsch, Ph. D.
(University of Oxford)
The Author is:

Visiting Professor of Physics and a founder member of the Centre for Quantum Computation at The Clarendon Laboratory, University of Oxford, and author of The Fabric of Reality and The Beginning of Infinity.

 

“Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”

~Albert Einstein~

OXFORD – It was recently discovered that the universe’s expansion is accelerating, not slowing, as was previously thought. Light from distant exploding stars revealed that an unknown force (dubbed “dark energy”) more than outweighs gravity on cosmological scales.

Unexpected by researchers, such a force had nevertheless been predicted in 1915 by a modification that Albert Einstein proposed to his own theory of gravity, the general theory of relativity. But he later dropped the modification, known as the “cosmological term,” calling it the “biggest blunder” of his life.

So the headlines proclaim: “Einstein was right after all,” as though scientists should be compared as one would clairvoyants: Who is distinguished from the common herd by knowing the unknowable – such as the outcome of experiments that have yet to be conceived, let alone conducted? Who, with hindsight, has prophesied correctly?

But science is not a competition between scientists; it is a contest of ideas – namely, explanations of what is out there in reality, how it behaves, and why. These explanations are initially tested not by experiment but by criteria of reason, logic, applicability, and uniqueness at solving the mysteries of nature that they address. Predictions are used to test only the tiny minority of explanations that survive these criteria.

The story of why Einstein proposed the cosmological term, why he dropped it, and why cosmologists today have reintroduced it illustrates this process. Einstein sought to avoid the implication of unmodified general relativity that the universe cannot be static – that it can expand (slowing down, against its own gravity), collapse, or be instantaneously at rest, but that it cannot hang unsupported.

This particular prediction cannot be tested (no observation could establish that the universe is at rest, even if it were), but it is impossible to change the equations of general relativity arbitrarily. They are tightly constrained by the explanatory substance of Einstein’s theory, which holds that gravity is due to the curvature of spacetime, that light has the same speed for all observers, and so on.

But Einstein realized that it is possible to add one particular term – the cosmological term – and adjust its magnitude to predict a static universe, without spoiling any other explanation. All other predictions based on the previous theory of gravity – that of Isaac Newton – that were testable at the time were good approximations to those of unmodified general relativity, with that single exception: Newton’s space was an unmoving background against which objects move. There was no evidence yet, contradicting Newton’s view – no mystery of expansion to explain. Moreover, anything beyond that traditional conception of space required a considerable conceptual leap, while the cosmological term made no measurable difference to other predictions. So Einstein added it.

Then, in 1929, Edwin Hubble discovered that the universe is expanding, consistently (within the observational accuracy of the day) with unmodified general relativity. So Einstein dropped the cosmological term. His doing so had nothing to do with Hubble being less blunder-prone; nor was Einstein deferring to Hubble’s superior prophetic abilities. It was just that the problem that the term was intended to solve no longer existed.

The new observations did not refute the existence of a cosmological term. They merely made it a bad explanation. Then, in 1998, came those new observations of a universe whose expansion is accelerating. As a result, the cosmological term that has been “reinstated” to account for the new observations is not quite the one that Einstein proposed and retracted. It is larger, for it now has to explain not just why the universe isn’t collapsing, but why its expansion is accelerating.

Einstein’s remark about having “blundered” is as misleading as the idea that he is “right after all.” The cosmological term is not something that should never have been proposed. Its introduction represented progress in understanding reality – as did its abandonment in light of Hubble’s discovery and its reinstatement in revised form to account for the new observations.

Likewise, the mid-twentieth century “Bohr-Einstein debate” about quantum theory is often misinterpreted as a personal clash between wizards. So counter-intuitive are quantum theory’s predictions that, under the leadership of one of its pioneers, Neils Bohr, a myth grew that there is no underlying reality that explains them. Particles get from A to B without passing through the intervening space, where they have insufficient energy to exist; they briefly “borrow” the energy, because we are “uncertain” about what their energy is. Information gets from A to B without anything passing in between – what Einstein called “spooky action at a distance.” And so on.

What these paradoxical interpretations have in common is that they abandon realism, the doctrine that a physical world, existing in reality, accounts for all of our experience. Anti-realism remains popular and appears in various guises in textbooks and popular accounts of quantum theory. But Einstein insisted that physical phenomena have explanations in terms of what he called “elements of reality.”

Fortunately, a minority of physicists, myself included, likewise side unequivocally with realism, by adopting Hugh Everett’s multiple-universes interpretation of quantum theory. According to this view, no particles exist where they have insufficient energy to be; it is simply that in some universes they have more energy than average, and in others, less. All alleged “paradoxes” of quantum theory are similarly resolved.

So, while most accounts say that Bohr won the debate, my view is that Einstein, as usual, was seeking an explanation of reality, while his rivals were advocating nonsense. Everett’s interpretation doesn’t make Einstein a demigod. But it does make him right.

Copyright: Project Syndicate, 2011.
www.project-syndicate.org

Astrophysics Library

 

"Pengembangan IPTEKS Keluarangkasaan akan membuka jalan-jalan terhadap dunia-dunia baru bagi peradaban umat manusia"

~Arip~

Advances in Spacecraft Technologies

Edited by: Jason Hall

ISBN 978-953-307-551-8, Hard cover, 596 pages
Publisher: InTech
Publication date: February 2011
Subject: Aerospace Engineering

The development and launch of the first artificial satellite Sputnik more than five decades ago propelled both the scientific and engineering communities to new heights as they worked together to develop novel solutions to the challenges of spacecraft system design. This symbiotic relationship has brought significant technological advances that have enabled the design of systems that can withstand the rigors of space while providing valuable space-based services. With its 26 chapters divided into three sections, this book brings together critical contributions from renowned international researchers to provide an outstanding survey of recent advances in spacecraft technologies. The first section includes nine chapters that focus on innovative hardware technologies while the next section is comprised of seven chapters that center on cutting-edge state estimation techniques. The final section contains eleven chapters that present a series of novel control methods for spacecraft orbit and attitude control.

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Para Peraih Nobel dari California Institue of Technology II

"Enthusiasm is followed by disappointment and even depression, and then by renewed enthusiasm."

*Murray Gell-Mann*

 

GEORGE WELLS BEADLE (1903–1989)

George W. Beadle was awarded the Nobel Prize in Physiology or Medicine in 1958 for his “one gene-one enzyme” theory of gene action. His early experiments with Drosophila revealed that even such an apparently simple characteristic as eye color was the result of a long series of genetically determined chemical reactions.

Later experiments with the bread mold Neurospora enabled him to conclude that each gene determined the structure of a particular enzyme, which in turn controlled a single chemical reaction. 

A pioneer in the field of biochemical genetics, the series of discoveries he made between 1941 and 1953 closed out the era of classical genetics à la Morgan and ushered in the molecular age.

Beadle came to Caltech in 1931, after earning his PhD in corn genetics from Cornell University and having been awarded a National Research Council Fellowship to do postdoctoral work in Thomas Hunt Morgan’s Division of Biology. 

He spent several subsequent years on other genetic research in collaboration with scientists at the Institut de Biologie Physico-Chimique in Paris, at Harvard, and at Stanford. In 1946, he became professor and chairman of the biology division at Caltech, where he remaineduntil 1960, when he was named chancellor of the University of Chicago.

After retiring from that position, he directed the American Medical Association’s Institute for Biomedical Research from 1968 to 1970. He also returned to experimental biology, working on a problem close to his heart: the origin of maize. 

DONALD ARTHUR GLASER (b. 1926)

 
Donald Glaser was awarded the Nobel Prize in Physics in 1960 for his invention of the bubble chamber. This instrument became widely used in physics research because it allowed scientists to observe the behavior of subatomic particles and to measure their paths precisely. 

In 1946, after completing his undergraduate work at the Case Institute of Technology in Cleveland, Glaser came to Caltech to pursue graduate study with Carl Anderson. He received his PhD in physics from the Institute in 1949. 


He then joined the physics faculty at the University of Michigan, where he taught and pursued research that led to the development of the bubble chamber. In 1959, Glaser left Michigan to teach at the University of California, Berkeley. He was named professor of physics and molecular biology in 1964. 

RUDOLF LUDWIG MÖSSBAUER (b. 1929)

 
Rudolf Mössbauer was a cowinner (with Robert Hofstadter) of the 1961 Nobel Prize in Physics for his discovery of the Mössbauer effect. He was 32 years old when he received the prize, one of the youngest scientists ever to be so honored. 

The effect that bears his name involves the production of gamma rays of a single, precise energy from the nuclei of atoms embedded in crystals. It is a yardstick that makes it possible to measure with an unprecedented sensitivity the effects of gravity, electricity, and magnetism on photons and atomic nuclei. 

Mössbauer first observed the effect in 1957, while still a graduate student at the Technical Academy of Munich. He received his PhD in 1958, and came to Caltech as a research fellow in 1960. He was named professor of physics in 1961. 

Mössbauer returned to Munich a few years later to join the physics faculty at the Technical Academy. He was a visiting professor of physics at Caltech in 1964. 

CHARLES HARD TOWNES (b. 1915)

 
Charles Townes was a corecipient (with the Soviet physicists Prokhorov and Basov) of the 1964 Nobel Prize in Physics for his work in the then-new field of quantum electronics, and particularly for his role in the invention of the maser and the laser.

Townes came to Caltech as a graduate student in 1937, and received his PhD in 1939. Later that year he became a member of the technical staff at Bell Labs, where he stayed until 1948. 

He then joined the faculty at Columbia University, and began the work that in 1953 produced the maser (microwave amplification by stimulated emission of radiation). From 1959 to 1961 he headed the Institute for Defense Analyses in Washington, D.C. He then served as provost and professor of physics at MIT for six years. 

 In 1967, he went to the University of California, Berkeley, where his pioneering program in radio and infrared astronomy led to the discovery of ammonia and water molecules in the interstellar medium. He was named emeritus in 1986.

RICHARD PHILLIPS FEYNMAN (1918-1988)

 
Richard Feynman shared the Nobel Prize in Physics (with Julian Schwinger and Tomonaga Shin’ichiro) in 1965 for his formulation of a comprehensive theory of quantum electrodynamics—how electrically charged particles interact with photons and with each other. 

His version of this theory, and its accompanying “Feynman diagrams”—intuitive, pictorial representations of interactions among elementary particles—revolutionized the way scientists think about these processes in many fields of physics.

After receiving his PhD from Princeton University in 1942, Feynman worked on the atomic bomb project, both at Princeton and at Los Alamos, New Mexico. 

At the end of the war, he joined the physics faculty at Cornell University, where he taught and continued his quantum electrodynamics research. In 1950, he became professor of theoretical physics at Caltech, where he remained for the rest of his career.

While at the Institute, he pursued a number of projects, including devising a quantum mechanical explanation of superfluidity, and developing (with Murray Gell-Mann) a theory of the weak force.

In 1968 he proposed a theory of “partons”—hypothetical hard particles inside the nucleus of the atom—that contributed to the understanding of quarks.

In 1986, Feynman became known to an even larger audience through his participation—and his famous ice-water experiment—on the Presidential Commission investigating the explosion of the Space Shuttle Challenger.

 

MURRAY GELL-MANN (b. 1929)

 
Murray Gell-Mann was awarded the Nobel Prize in Physics in 1969 for his efforts to develop a unifying scheme of classification for subatomic particles and their interactions.

Gell-Mann received his doctorate in physics from MIT in 1951, at the age of 21. In 1952 he joined the Institute for Nuclear Studies at the University of Chicago, where his research yielded the first definition of the quantum property of “strangeness.” 

The concept of strangeness helped explain certain particle decay patterns that had long mystified scientists. Gell-Mann came to Caltech in 1955. Six years later, he first proposed his “Eightfold Way,” a scheme for classifying protons and neutrons into families.

This work led him to theorize further that the behavior of known particles might be explained in terms of the even more fundamental building blocks he dubbed “quarks” (the word is borrowed from James Joyce’s Finnegans Wake). Gell-Mann was appointed Robert Andrews Millikan Professor of Theoretical Physics in 1967.

He now lives in Santa Fe, New Mexico, where he is associated with the Santa Fe Institute, an interdisciplinary think-tank he cofounded in 1984.

Sumber: 

California Institute of Technology

http://www.pma.caltech.edu/GSR/physics.html

Nobel Prize