Re: I don't get it
- From: "Sue..." <suzysewnshow@xxxxxxxxxxxx>
- Date: Fri, 29 Feb 2008 12:05:42 -0800 (PST)
On Feb 15, 12:29 pm, pete.ha...@xxxxxxxxxxxxxx wrote:
I've started the relativity module of my physics degree, and I'm
having some conceptual trouble with it.
I'm fine with the maths and I can do the questions - I got 100% in the
first long answer test. But I just don't *get* it.
No explanation of the twins paradox makes much sense to me. Everyone
just points out to me that the travelling twin is accelerate, and that
makes them different. But the Lorentz transformation don't seem to say
anything about acceleration as far as I can make out, which would mean
that they don't agree with the conceptual part of relativity (or what,
I understand, has been observed experimentally).
It is also a little unclear to me why we see relativistic effects. One
minute I am told time dilation is a consequence of the speed of light
being the same in all reference frames, then someone starts talking
about the time it takes light signals to come from a clock. In the
latter case it would seem the dilation isn't 'real' at all, whereas in
the former case it is.
I'm having trouble getting help with my confusion. The more people
seem to know about relativity, the more difficult it is to communicate
with them.
There is no paradox nor differential ageing of the twins just
so you adhere to the mathematical description of proper time.
"Proper Time"
http://farside.ph.utexas.edu/teaching/em/lectures/node50.html
Proper time, despite its name, has a spatial component
that must be respected with complex numbers that preserve
the difference in a spatial and temporal displacement.
http://en.wikipedia.org/wiki/Imaginary_number
<< if you know about complex numbers you will notice
that the space part enters as if it were imaginary
R2 = (ct)2 + (ix)2 + (iy)2 + (iz)2 = (ct)2 + (ir)2
where i^2 = -1 as usual. This turns out to be the essence
of the fabric (or metric) of spacetime geometry - that
space enters in with the imaginary factor i relative to time.
http://www.nrao.edu/~smyers/courses/astro12/speedoflight.html
<< It is to be found rather in the fact of his
recognition that the four-dimensional space-time
continuum of the theory of relativity, in its most
essential formal properties, shows a pronounced
relationship to the three-dimensional continuum
of Euclidean geometrical space. 1 In order to
give due prominence to this relationship, however,
we must replace the usual time co-ordinate t
by an imaginary magnitude
sqrt (-1)
ct proportional to it. Under these conditions,
the natural laws satisfying the demands of the
(special) theory of relativity assume mathematical
forms, in which the time co-ordinate plays exactly
the same role as the three space co-ordinates. >>
--A. Einstein
http://www.bartleby.com/173/17.html
Sue...
.
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