Re: LIGO.
- From: "Sue..." <suzysewnshow@xxxxxxxxxxxx>
- Date: 8 Feb 2007 16:29:42 -0800
On Feb 8, 5:31 pm, "Ken S. Tucker" <dynam...@xxxxxxxxxxxx> wrote:
On Feb 8, 1:25 pm, "Sue..." <suzysewns...@xxxxxxxxxxxx> wrote:
On Feb 8, 1:50 pm, sal <pragmat...@xxxxxxxxxx> wrote:
On Thu, 08 Feb 2007 17:44:25 +0000, Tom Roberts wrote:
dlzc wrote:
Bullion wrote:
What is a wave in space-time?Good question. Would it be resolvable, in some part, in space-only?
No.
The LIGO interferometer mirrors are held apart with constant spacelike
proper distance by the inter-atomic force of their supports and beam
pipes. The lasers measure the distance between the mirrors along a null
geodesic. Their signal is the difference between the lengths of these two
geodesics. They usually describe this as a variation in the distance
between the mirrors (implicitly using c=constant all along the light
path).
Say what? Tom, would you be so kind as to expand that paragraph to
include a definition of "distance" in each place where you used it, and
please explain what you meant by the "length" of each of the geodesics
which are being compared? I'm sorry, but as written, I didn't understand
what you said.
Distance along a null geodesic could mean 3-d _coordinate_ distance of the
endpoints projected into 3-d spacetime, _coordinate_ time difference, or
proper distance (which is zero).
Sal,
Clearly, you are unfamilar with the semantic-operator. It is
hard to find in math texts but can save you a lot of unpleasent
operations when dealing with an expression like this:
<<.. 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
http://www.aoc.nrao.edu/~smyers/courses/astro12/speedoflight.html
;-)
Sue...
No Sue, you're out of date,
We received an order to update that program,
back in the 1970's.http://physics.trak4.com/
((I'm just catching up on the mail)).
Are we the only SOBs we got that 1983 update??
Many thanks for the new index. Were you going to
tell us which paper resolves the Tate anomaly so
we can cheat on the homework?
It won't be necessary because I know the trick.
I'll read the last one first and have comments in
your MST thread by tomorrow. :o)
Sue...
Ken
.
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