Natural Science Forum / Physics / Relativity / December 2004

I would agree with that.  I did a degree in math and studied GR from
Landau - Classical Theory of Fields.  The math was accessible but the
physics took some time to grasp.  It was not until I had studied the Feynman
Lectures, studied SR from Render - Introduction to SR and read another
book - Ohanian an Ruffini - Gravitation and Space-time that I began to
actually understand it.  When I started posting here about 5 years ago now I
thought because I read Landau and other references I understood it - it
became glaringingly obvious from posts of people who actually did understand
it I did not.  I am still doing that even after all these years.  In a sense
it is rather interesting because most people think the math is the hard
part - it is not - understanding the physics is.  It is even more
interesting in light of the crank brigades claim you often see around here
it is just a math theory and can not represent reality.  When you study the
real deal the exact opposite becomes glaringly obvious.

Thanks
Bill

Here at UW Madison we usually teach GR as an undergrad class once a year.  
A few years ago we used a pre-printed version of Hartle.  I should check
out the finished version sometime.

I agree with everybody...(in this thread!)

My post is just for fun, but it's truthful....

I was about 4-years old and tumbled down a stair case,
my a.s et al discovered the Quantum Gravitational Field Theory.
As I was not hurt much, I took it upon myself from time to time to
roll down stairs, shoot not much different than playing tackle
football.

As Mr. Shubert suggests, I too found the relation of red-shift, photon
energy and g-potential, as related to a spacetime *warp* to be very
sensible, in fact it looked like common sense, once one appreciates
that measurement (surveying) is defined by light rays.

Classical GR isn't really that difficult, I understood it in HS,
heck even W. Pauli wrote a fine treatment at age 19.

The hard part about GR is learning  what you don't know,
specifically where it interfaces with EM and QT.

As some may recall, I question how the concept germaine
to GR that all motion, including accelerated motion is relative,
in the presence of the Lorentz force (f_u = q*F_uv U^v).

I'm particularily frustrated that f_u is regarded as an absolute
accelerating force, so I've argued f_u=0, from the PoV of strict
GR. In my view, that's where concentration of effort is reasonable,
to experiment with the theoretics of GR.

Specifically the historical assumption that the geodesic given by
the intrinsic derivative DU^u =0, that is a Law in GR becomes subjegate
to the Lorentz force ((by prostitution,sorry)), to form

DU^u = f^u   === Lorentz Force

is an abomination of GR!

Who's the boss? GR or Lorentz Force?  (rhetorical).

Classically, we disregard the General Theory of Relativity
of motion described by

DU^u=0

so that Lorentz's  f_u  =/=0.

I turn to the experimentalist's, specifically to QT, and find
it's necessary to set f_u=0 in accord with DU^u=0, and therein,
(if true), find GR underwrites the otherwise adhoc QT.

QT has good support experimentally, but is shaky by principle.
However, I find GR actually predicts QT, and underwrites the
foundation for Planck's hypothesis, that has been subsequently
evolved and improved mathematically.

To wind up, I think GR is a theory in progress.
Ken S. Tucker