Showing posts sorted by relevance for query peter galison. Sort by date Show all posts
Showing posts sorted by relevance for query peter galison. Sort by date Show all posts

Saturday, May 19, 2007

Galison: Poincare and Einstein

A colleague and I recently discussed Peter Galison and his book Einstein's Clocks, Poincare's Maps: Empires of Time . (See also here and here.) The book explores how practical concerns of the era (in particular, clock synchronization -- important for longitudinal navigation as well as for the European train system) influenced the discovery of special relativity.

Both my friend and I are great admirers of Galison. After earning his doctorate in the history of science, he wrote a second dissertation in particle theory under Howard Georgi while a Junior Fellow at Harvard. Other than particle theorists turned science historians like Sam Schweber or Abraham Pais (see here and here), I can't think of anyone more qualified to work on the (underdeveloped) history of modern physics.

When I learned about special relativity as a kid, I first went through a phase of suspicion about Einstein's operational approach -- how could one be sure, I wondered, that light beams were the best primitive for the operation and synchronization of clocks? After I accepted this idea, I was shocked that someone could be so imaginative as to come up with his clever gedanken experiments, involving moving trains, light beams, lattices of clocks. I thought to myself -- I could have never invented that! It was only much later that I learned about his patent office work on clocks and how synchronization of time between distant rail stations was an important practical problem of the day. I agree completely with Galison that practical concerns had a strong influence on both Einstein's and Poincare's thinking.

NYTimes: ...Einstein's relativity has long been regarded by scholars as a monument to the power of abstract thought. But if Dr. Peter Galison, 48 -- a Harvard professor of the history of science and of physics, a pilot, art lover and nascent filmmaker -- is right, physics and Einstein have flourished more in their connections to the world than in any ivory tower aloofness. And one clue to the origin of relativity can be found in something as mundane and practical as a 19th-century train schedule. ''It's in as plain sight as it could possibly be,'' he said.

As Dr. Galison relates, before the advent of factories began to standardize life, and railroad systems with crisscrossing tracks made it imperative to know which train was where and when, there were too many times, one for every village.

In the last part of the 19th century, the coordination of clocks and the standardization of time had engaged the passions of nations, business leaders, astronomers and philosophers. The patent office in Bern, Switzerland, where Einstein worked, was a clearinghouse for patents on the synchronization of clocks.

In New England, the Harvard and Yale observatories were competing to sell time signals to the public, and in Paris pneumatic tubes snaked under the streets to synchronize the city's clocks with blasts of air. Far from being a bit of abstraction by a loner genius, the clocks that Einstein used as examples in his papers were as familiar then as computers are today.

...In addition to all his high-flown academic activities, Poincaré was immersed in practical work. He was a mining inspector, for example. Most important, he was deeply involved with the French Board of Longitude, even serving as president, sending teams of soldiers and surveyors across the oceans to map the far-flung empire.

Coordinated clocks were central to this enterprise. To measure the longitude of some mountain or port or gold mine in the New World, it was necessary to measure the difference between the time some star crossed the meridian there and the time it did back in Paris. The leaders and rivals in filling in this ''electric world map,'' as Dr. Galison calls it, were England and France, even though for several years they were embarrassingly unable to agree on the distance between their own principal observatories, Greenwich and Paris. Paris lost out to Greenwich as the locus of zero longitude, but in 1909 Poincaré used the Eiffel Tower to broadcast time signals to the world.

...In his papers Einstein was always using modern machines to illustrate his ideas, Dr. Galison noted. ''There is something wonderful about Einstein invoking trains and telegraphs to get a transformation of space-time, Poincaré turning the Eiffel Tower into a radio,'' Dr. Galison said.

''In the long run I think what's happened to them is that we, partly through our own doing and partly through our doing to them, removed these physicists from the concrete situations that they were involved in. And I think in a way lose some of the fascination that these ideas had for them and still could have for us in a way.''

It's our loss, he said.


Galison: "My question is not how different scientific communities pass like ships in the night,'' he wrote in Image and Logic. ''It is rather how, given the extraordinary diversity of the participants in physics -- cryogenic engineers, radio chemists, algebraic topologists, prototype tinkerers, computer wizards, quantum field theorists -- they speak to each other at all."

Thursday, April 30, 2015

DNA Dreams at Harvard



This is a panel discussion of the documentary film DNA Dreams (see below), about BGI and its Cognitive Genomics Lab.
DNA DREAMS

Moderator: Dr. Evelynn Hammonds, Director of the Project on Race & Gender in Science & Medicine, Hutchins Center for African & African American Research/Barbara Gutmann Rosenkrantz Professor of the History of Science

Panelists include: (L to R)
1. George Church, Robert Winthrop Professor of Genetics, Harvard Medical School
2. Bregjte van der Haak, Filmmaker
3. Arthur Kleinman, Director of the Harvard University Asia Center and Professor of Anthropology and Medical Anthropology at Harvard University
4. Peter Galison, Pellegrino University Professor, Director of the Collection of Historical Scientific Instruments, Harvard University
Peter Galison is dismissive of "single parameter" measures of cognitive ability. George Church replies quite effectively. Certainly anyone who has thought seriously about IQ or g knows that it is only a crude measure of (compressed approximation to) a multi-dimensional set of mental abilities. I wonder how Peter would react to learning that his grandchild would be born with a mutation depressing the meaningless "single parameter" in question to an SD below normal. Would he just shrug it off as unimportant?

I believe this is the entire documentary:

Thursday, April 16, 2009

James Yang graphic art

A colleague introduced me to the artist James Yang, whose work seems to have a special appeal for geeky scientists like me. Below are a couple of nice images from his portfolio, with my own suggested captions :-)


"Physics department" (Peter Galison: ''My question is not how different scientific communities pass like ships in the night,'' he wrote in Image and Logic. ''It is rather how, given the extraordinary diversity of the participants in physics -- cryogenic engineers, radio chemists, algebraic topologists, prototype tinkerers, computer wizards, quantum field theorists -- they speak to each other at all.'' :-)




"Discovering China"



"The biotech century"

Friday, November 27, 2015

Feynman's War


Radar and nuclear weapons could not have been developed without the big brains.
Feynman’s War: Modelling Weapons, Modelling Nature

Peter Galison*

What do I mean by understanding? Nothing deep or accurate—just to be able to see some of the qualitative consequences of the equations by some method other than solving them in detail. -- Feynman to Welton, 10 February 1947.


... The fundamental problem facing theorists on the bomb project was this: in a limited time, they had to produce accurate, quantitative predictions of the efficiency and critical mass of the chain reaction in a wide variety of geometries. There was no time to devise detailed models for each configuration of fissile material and neutron-reflecting tampers, just as on the radar project physicists could not start calculating ab initio for each new arrangement of waveguides and junctions. At MIT, the radar physicists [ e.g., Julian Schwinger ] had to provide effective circuits for the various waveguides so the radio engineers could manipulate them. Similarly, for the Los Alamos physicists facing engineers, architects, and experimentalists, much rode on the theorists’ ability to modularise aspects of their work so it could be passed to non-theorists. They had to figure out ways of characterising the ‘neutronics’ using certain building blocks—whether those building blocks were standardised effective amplifiers or new theoretical techniques to model neutron diffusion.

Feynman learned from and contributed to this culture of modularity. Whether he was grappling with the human efficiency of crunching numbers using Marchant calculators, or inventing easily taught rules for tracking neutrons in tampers, Feynman developed highly movable theoretical modules. These simple, often visualisable mechanisms took complex human, physical and calculational configurations and sorted them into simpler parts that could be recombined in a myriad of ways to calculate rapid, approximate, yet reliable answers. It was a kind of theory particularly appropriate to the constantly rearranged devices they were to represent. ...
Note Feynman seems to spell Corollary as Coralary repeatedly. In other notebooks he often spelled gauge (as in gauge theory) as guage. These are commonly used words in physics. I always suspected that, as far as such constructs are well-defined, Feynman's mathematical ability was superior to his verbal ability. See Feynman's Cognitive Style.

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