That New Critically Acclaimed Bio on Paul Dirac [Relativity]

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From: J Seymour MacNicely on 31 Mar 2010 15:19

On page 42, Graham Farmelo, in speaking of Dirac's attendance to the
early lectures of Charlie Broad as per Relativity and the Pythagorean
theorem, has this to say . . .

"In the space-time of (SR), things are different: the square of the
distance between two points in space-time is equal to the sum of the
squares of the spatial lengths *minus* the square of the time. Dirac
later recalled 'the tremendous impact' on him of Broad's writing down
that minus sign."

I should say so! But doesn't this strike you as more in the realm of
GR than SR? In other words, with a purely geometric observation of
distance between the three points of a right triangle--how can TIME
enter into the consideration, where there is no event involved? OR,
is this to say that in curved Riemannian (or geodesic) space, where
space is curved by an influence of gravity, space IS AN EVENT now to
be called "space-time"? TIME being the essence of gravity
(acceleration) and therefore that curvature. I.e., in space without
mass & gravity, such space would be Euclidian, where TIME is not of
the essence. Not of the essence because not of an event of masses
accelerating in time to be observed.

Or what?
--
JM

From: J Seymour MacNicely on 31 Mar 2010 16:45

On Mar 31, 2:19 pm, J Seymour MacNicely <jpd...(a)gmail.com> wrote:
> On page 42, Graham Farmelo, in speaking of Dirac's attendance to the
> early lectures of Charlie Broad as per Relativity and the Pythagorean
> theorem, has this to say . . .
>
> "In the space-time of (SR), things are different: the square of the
> distance between two points in space-time is equal to the sum of the
> squares of the spatial lengths *minus* the square of the time. Dirac
> later recalled 'the tremendous impact' on him of Broad's writing down
> that minus sign."
>
> I should say so! But doesn't this strike you as more in the realm of
> GR than SR? In other words, with a purely geometric observation of
> distance between the three points of a right triangle--how can TIME
> enter into the consideration, where there is no event involved? OR,
> is this to say that in curved Riemannian (or geodesic) space, where
> space is curved by an influence of gravity, space IS AN EVENT now to
> be called "space-time"? TIME being the essence of gravity
> (acceleration) and therefore that curvature. I.e., in space without
> mass & gravity, such space would be Euclidian, where TIME is not of
> the essence. Not of the essence because not of an event of masses
> accelerating in time to be observed.
>
> Or what?
> --
> JM

From: J Seymour MacNicely on 1 Apr 2010 01:02

On Mar 31, 3:45 pm, J Seymour MacNicely <jpd...(a)gmail.com> wrote:
> On Mar 31, 2:19 pm, J Seymour MacNicely <jpd...(a)gmail.com> wrote:
>
>
>
> > On page 42, Graham Farmelo, in speaking of Dirac's attendance to the
> > early lectures of Charlie Broad as per Relativity and the Pythagorean
> > theorem, has this to say . . .
>
> > "In the space-time of (SR), things are different: the square of the
> > distance between two points in space-time is equal to the sum of the
> > squares of the spatial lengths *minus* the square of the time. Dirac
> > later recalled 'the tremendous impact' on him of Broad's writing down
> > that minus sign."
>
> > I should say so! But doesn't this strike you as more in the realm of
> > GR than SR? In other words, with a purely geometric observation of
> > distance between the three points of a right triangle--how can TIME
> > enter into the consideration, where there is no event involved? OR,
> > is this to say that in curved Riemannian (or geodesic) space, where
> > space is curved by an influence of gravity, space IS AN EVENT now to
> > be called "space-time"? TIME being the essence of gravity
> > (acceleration) and therefore that curvature. I.e., in space without
> > mass & gravity, such space would be Euclidian, where TIME is not of
> > the essence. Not of the essence because not of an event of masses
> > accelerating in time to be observed.
>
> > Or what?
> > --
> > JM

From: Just Me on 1 Apr 2010 12:59

So, maybe the physicists hanging around these groups never heard of
Paul Dirac?

On Apr 1, 12:02 am, J Seymour MacNicely <jpd...(a)gmail.com> wrote:
> On Mar 31, 3:45 pm, J Seymour MacNicely <jpd...(a)gmail.com> wrote:
>
>
>
> > On Mar 31, 2:19 pm, J Seymour MacNicely <jpd...(a)gmail.com> wrote:
>
> > > On page 42, Graham Farmelo, in speaking of Dirac's attendance to the
> > > early lectures of Charlie Broad as per Relativity and the Pythagorean
> > > theorem, has this to say . . .
>
> > > "In the space-time of (SR), things are different: the square of the
> > > distance between two points in space-time is equal to the sum of the
> > > squares of the spatial lengths *minus* the square of the time. Dirac
> > > later recalled 'the tremendous impact' on him of Broad's writing down
> > > that minus sign."
>
> > > I should say so! But doesn't this strike you as more in the realm of
> > > GR than SR? In other words, with a purely geometric observation of
> > > distance between the three points of a right triangle--how can TIME
> > > enter into the consideration, where there is no event involved? OR,
> > > is this to say that in curved Riemannian (or geodesic) space, where
> > > space is curved by an influence of gravity, space IS AN EVENT now to
> > > be called "space-time"? TIME being the essence of gravity
> > > (acceleration) and therefore that curvature. I.e., in space without
> > > mass & gravity, such space would be Euclidian, where TIME is not of
> > > the essence. Not of the essence because not of an event of masses
> > > accelerating in time to be observed.
>
> > > Or what?
> > > --
> > > JM

From: Just Me on 2 Apr 2010 04:35

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