Re: Why is the Speed Of Light Constant?


Hexenmeister wrote:

"SCW" <doune60@xxxxxxxxxxxxx> wrote in message
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Hexenmeister wrote:

"SCW" <doune60@xxxxxxxxxxxxx> wrote in message
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bsr3997@xxxxxxxxxxx wrote:
N:dlzc D:aol T:com (dlzc) wrote:
Dear Chris:

"Chris" <nimbo@(no-spam)ukonline.co.uk> wrote in message
news:VypMf.62771$DM.60988@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
There is no why, it is an experimental result. That
is that.

Actually, c is a constant *by definition*. The meter is defined
by c and time...

David A. Smith

Nice dodge ;) That doesn't explain why it was constant before the
definition was changed to the current one.

Bruce richmond

Fact is, c seems to be constant for the same reason that Plank's
constant is constant (!)
It just fits - more engineering than science.

SCW
Mathematicians call that "circularity", deriving what is assumed
in the first instance.
It is because it say it is, therefore it is.
Such argument is pointless.
Androcles.

Agreed.

SCW
Interestingly, the postulate Einstein used
"light is always propagated in empty space with a definite velocity c
which is independent of the state of motion of the emitting body "
together with his own definition of time:
"we establish by definition that the ``time'' required by light to travel
from A to B equals the ``time'' it requires to travel from B to A."
Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/

has since become
"Einstein's theory of special relativity results from two statements -- the
two basic postulates of special relativity: The speed of light is the same
for all observers, no matter what their relative speeds."
Ref: http://www2.slac.stanford.edu/vvc/theory/relativity.html

"The speed of light is the same for all observers in uniform motion"
http://theory.uwinnipeg.ca/mod_tech/node133.html

"the speed of light in free space has the same value C in all inertial
systems."
http://hepth.hanyang.ac.kr/~kst/lect/relativity/x146.htm

"The speed of light in vacuum has the same value c in all inertial frames of
reference."
http://nobelprize.org/physics/educational/relativity/postulates-1.html

"The relative rate of motion between any observer and any ray of light is
always the same, 300,000 km/sec (186,000 mi/sec). "
http://www.egglescliffe.org.uk/physics/relativity/post1.html

"The speed of light through a vacuum (300,000,000 m/s or 186,000 mi/sec) is
constant as observed by any observer, moving or stationary. "
http://www.glenbrook.k12.il.us/gbssci/phys/Class/relativity/u7l1a.html


That is the perfect example of circularity.
Einstein "derives" what everyone thought was a postulate, from which they
are able to "prove" what they assumed, and none can quote the postulate.
Androcles.

Androcles, I'm shocked! What an impressive post.

What is your opinion? Do you think that c is constant?

You know my view - we can only know the velocity of light from the last
reflected surface.



SCW

.

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