Day # 4 : Oct-07 : Category-Theoretical Physics

[Ivy Aspire GMAT Prep]

Hi,
Category: Theoretical Physics
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In June 1905, twenty-six-year-old Albert Einstein submitted a
technical article to the Annals of Physics in which he came to grips
with a paradox about light that had first troubled him as a teenager,
some ten years earlier. Upon turning the final page of Einstein's
manuscript, the editor of the journal, Max Planck, realized that the
accepted scientific order had been overthrown. Without hoopla
or fanfare, a patent clerk from Bern, Switzerland, had completely
overturned the traditional notions of space and time and replaced
them with a new conception whose properties fly in the face of
everything we are familiar with from common experience.

The paradox that had troubled Einstein for a decade was this. In the
mid-1800s, after a close study of the experimental work of the
English physicist Michael Faraday, the Scottish physicist James Clerk
Maxwell succeeded in uniting electricity and magnetism in
the framework of the electromagnetic field. If you've ever been on a
mountaintop just before a severe thunderstorm or stood close
to a Van de Graaf generator, you have a visceral sense of what an
electromagnetic field is, because you've felt it. In case you
haven't, it is somewhat like a tide of electric and magnetic lines of
force that permeate a region of space through which they pass.
When you sprinkle iron filings near a magnet, for example, the orderly
pattern they form traces out some of the invisible lines of
magnetic force. When you take off a wool sweater on an especially dry
day and hear a crackling sound and perhaps feel a
momentary shock or two, you are witnessing evidence of electric lines
of force generated by electric charges swept up by the fibers
in your sweater. Beyond uniting these and all other electric and
magnetic phenomena in one mathematical framework, Maxwell's
theory showed—quite unexpectedly—that electromagnetic disturbances
travel at a fixed and never-changing speed, a speed that
turns out to equal that of light. From this, Maxwell realized that
visible light itself is nothing but a particular kind of
electromagnetic wave, one that is now understood to interact with
chemicals in the retina, giving rise to the sensation of sight.
Moreover (and this is crucial), Maxwell's theory also showed that all
electromagnetic waves—visible light among them—are the
epitome of the peripatetic traveler. They never stop. They never slow
down. Light always travels at light speed.

All is well and good until we ask, as the sixteen-year-old Einstein
did, What happens if we chase after a beam of light, at light
speed? Intuitive reasoning, rooted in Newton's laws of motion, tells
us that we will catch up with the light waves and so they will
appear stationary; light will stand still. But according to Maxwell's
theory, and all reliable observations, there is simply no such
thing as stationary light: no one has ever held a stationary clump of
light in the palm of his or her hand. Hence the problem.
Luckily, Einstein was unaware that many of the world's leading
physicists were struggling with this question (and were heading
down many a spurious path) and pondered the paradox of Maxwell and
Newton largely in the pristine privacy of his own thoughts
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Courtesy: The Elegant Universe, Brian Greene

Note: You can download the book from
http://www.polvoestelar.com.mx/babilonia/Libros/Brian%20Greene/Brian%20Greene%20-%20The%20Elegant%20Universe.pdf

Have a nice day!

Thanks & Regards,
Siva Sankaran B

Disclaimer: Please use Google Chrome to have a better reading
experience!

[Amit Shivhare]

Hi Siva,

 

Please add the Arvind email id,copied in the cc, in the ivy - google group.

 

Thanks,

Amit

[Ashish Ramesh]

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From: Amit Shivhare <amit.sh...@gmail.com>
To: ivy-aspire...@googlegroups.com
Cc: arvind....@gmail.com
Sent: Monday, October 10, 2011 7:43 PM
Subject: Re: Day # 4 : Oct-07 : Category-Theoretical Physics

Hi Siva,

 

Please add the my email id, in the ivy - google group. It looks like it has expired.

 

Thanks,

Ashish