A strange idea..

Somebody in sci.physics explained how after the BB space is expanding,
and tha tcauses the redshift of far away stars (spectral shift).
I then remarked that you can also look at space expanding as
'the quantum vacuum expanding', and in a way, 'the aether expanding',
as clearly it is just a cover up term for 'some substance in the vacuum'.

When we look at *propagation speed* we see that propagation speed in
a denser medium is usually higher (sound travels for example faster in water
then in air).
So, when the density was higher (of the quantum vacuum, or aether), perhaps
(here we come) the propagation speed was higher.
We know wavelength = propspeed / freq, or f = p / w, so if p was higher then
f should be higher, if wavelength did not change. (f.w = p).
mmm, does not figure, maybe wavelength changed....
Ah, prop speed is lower now, our 'ruler' has no, problem...

But he interesting thing from this is that *propagation speed changes*.
In a denser universe (just after the big bang) lightspeed would be much greater!
(assuming light travels in a 'medium' or 'aether' or 'quantum vacuum').
Shoot it all down, by all means, but the fast early 'FTL' expansion of the
BB it explains?

Now the predictive part:
What would happen if we measure lightspeed now, and one year from now?
Do our rulers also change?
Does lightspeed change (get slower as universe expands)?

Not sure about any of this, what is the concensus ATM?

(and does it suck) ;-)

"Jan Panteltje" wrote in message
news:1128504468.eaef6ea1712576c6ea5e6e66a2dcc5d8@t eranews...

Now the predictive part:
What would happen if we measure lightspeed now, and one year from now?
Do our rulers also change?
Does lightspeed change (get slower as universe expands)?

Not sure about any of this, what is the concensus ATM?

The scientific reply is to suggest you research
the observational limits on the evolution of
fundamental constants. I think there are quite
tight limits on the fine structure constant that
may constrain your idea as it is related to the
speed of light.

George

Dear Jan Pantelje:

(sorry to talk over your shoulder George)

"George Dishman" wrote in message
...

"Jan Panteltje" wrote in message
news:1128504468.eaef6ea1712576c6ea5e6e66a2dcc5d8@t eranews...

Now the predictive part:
What would happen if we measure lightspeed now, and one
year from now?

With the same instruments, you'd get the same result. And since
you'd use TWLS measurement to set up your apparatus each time...

Do our rulers also change?

A ruler isn't used. But the Earth's equatorial circumference
(the original definition of the meter) is neither increasing nor
decreasing as much as 1 part in 10^11 annually (maybe 1 part in
10^14). So "Hubble expansion" due to a secular variation in c is
out.

Does lightspeed change (get slower as universe expands)?

Why does light appear to redshift when being produced in a place
with higher gravity (curvature)? Doesn't curvature produce
"gravitational time dilation"? Wouldn't a younger, more dense
Universe have higher curvature than at a later time? c doesn't
have to change to get redshift.

Not sure about any of this, what is the concensus ATM?

The scientific reply is to suggest you research
the observational limits on the evolution of
fundamental constants. I think there are quite
tight limits on the fine structure constant that
may constrain your idea as it is related to the
speed of light.

Yes. But this allows/requires other constants to shift along
with c, to constrain a shift in alpha to 1 part in 10^8 in 13+
Gy. It only makes the problem of variable c into a sticky
nightmare.

David A. Smith

On a sunny day (Wed, 5 Oct 2005 12:45:48 +0100) it happened "George Dishman"
wrote in :


"Jan Panteltje" wrote in message
news:1128504468.eaef6ea1712576c6ea5e6e66a2dcc5d8@ teranews...

Now the predictive part:
What would happen if we measure lightspeed now, and one year from now?
Do our rulers also change?
Does lightspeed change (get slower as universe expands)?

Not sure about any of this, what is the concensus ATM?

The scientific reply is to suggest you research
the observational limits on the evolution of
fundamental constants. I think there are quite
tight limits on the fine structure constant that
may constrain your idea as it is related to the
speed of light.

George
Thank you George, you are as always quite helpful.
But not so much the limits but 'trend' (direction) of lightspeed I
would like to know (if it changes at all).
From the current reference frame.
:-)

"Jan Panteltje" wrote in message
news:1128518968.b659499edebacbb459472beae794a4e1@t eranews...
On a sunny day (Wed, 5 Oct 2005 12:45:48 +0100) it happened "George
Dishman"
wrote in :


"Jan Panteltje" wrote in message
news:1128504468.eaef6ea1712576c6ea5e6e66a2dcc5d8 @teranews...

Now the predictive part:
What would happen if we measure lightspeed now, and one year from now?
Do our rulers also change?
Does lightspeed change (get slower as universe expands)?

Not sure about any of this, what is the concensus ATM?

The scientific reply is to suggest you research
the observational limits on the evolution of
fundamental constants. I think there are quite
tight limits on the fine structure constant that
may constrain your idea as it is related to the
speed of light.

George
Thank you George, you are as always quite helpful.

Thanks Jan, I try.

But not so much the limits but 'trend' (direction) of lightspeed I
would like to know (if it changes at all).
From the current reference frame.
:-)

David has already mentioned this. There are
limits on the change of alpha which are very
small, basically no detectable change in
billions of years. However, c could change as
long as other parameters do so in step. Your
problem then is to see whether those other
changes would affect say spectral lines in
such a way that the combination results in
the observed red shift. That won't be so easy
but essentially you have to come up with
proposed combinations of change and test them.

George

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:hjQ0f.2777$lq6.2675@fed1read01...
Dear Jan Pantelje:

(sorry to talk over your shoulder George)

No problem David, it's a public group.

Why does light appear to redshift when being produced in a place with
higher gravity (curvature)? Doesn't curvature produce "gravitational time
dilation"? Wouldn't a younger, more dense Universe have higher curvature
than at a later time? c doesn't have to change to get redshift.

If V(x,y,z,t) is the gravitational potential at some
event, then it is obvious that partial dV/dx is zero
everywhere for a homogenous, isotropic universe (over
large scales) and similarly for y and z, but what can
you say about partial dV/dt in say an FRW universe?

Does the question mean anything anyway or is it "not
even wrong"?

George

On a sunny day (Wed, 5 Oct 2005 15:14:09 +0100) it happened "George Dishman"
wrote in :

But not so much the limits but 'trend' (direction) of lightspeed I
would like to know (if it changes at all).
From the current reference frame.
:-)

David has already mentioned this. There are
limits on the change of alpha which are very
small, basically no detectable change in
billions of years. However, c could change as
long as other parameters do so in step. Your
problem then is to see whether those other
changes would affect say spectral lines in
such a way that the combination results in
the observed red shift. That won't be so easy
but essentially you have to come up with
proposed combinations of change and test them.

George
Yes, been busy, but was thinking about this.
It seems to me that if the propagation speed of the light changed,
and we know frequency x wavelength = speed, and we know there is
some redshift, that then the wavelength must have changed.
This is trcky, I will try to explain why:
If they measured wavelength with a grating, took c for constant,
and found longer wavelength for light from early universe, they
could deduce redshift.
But if they measured *frequency* ... no they could not have, because
that would violate the formula!
I think they MUST have measured with a grating!
See this is the fun part, there are these 3 variables, and these are
related....
Only way I see I could measure frequency (of light) is to mix it with a
known light monochromatic source and use the differece frequency, hopefully
in the radio range.... Not sure they did that, not sure anybody did that.

So, anyways things seem to figure if that redshift was measured as wavelenght.
Very tricky to deduce one from the other, so now I will read David's post.
Regards
Jan

Dear George Dishman:

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox
wrote in message news:hjQ0f.2777$lq6.2675@fed1read01...
Dear Jan Pantelje:

(sorry to talk over your shoulder George)

No problem David, it's a public group.

It can also be considered rude, that is why the preface.

Why does light appear to redshift when being produced in
a place with higher gravity (curvature)? Doesn't curvature
produce "gravitational time dilation"? Wouldn't a younger,
more dense Universe have higher curvature than at a later
time? c doesn't have to change to get redshift.

If V(x,y,z,t) is the gravitational potential at some
event, then it is obvious that partial dV/dx is zero
everywhere for a homogenous, isotropic universe (over
large scales) and similarly for y and z, but what can
you say about partial dV/dt in say an FRW universe?

I would guess.. the spatial relations simply require that the
redshift (if any) be specular. And dV/dt should be non-zero
also, but Bjoern is the only FRW expert I have come across.

Does the question mean anything anyway or is it "not
even wrong"?

I think it is redshift, but let's see if Bjoern is lurking...

David A. Smith

"Jan Panteltje" wrote in message
news:1128540488.60e7d7554f18e0cdcd2f8823733fc4d5@t eranews...
On a sunny day (Wed, 5 Oct 2005 15:14:09 +0100) it happened "George
Dishman"
wrote in :

But not so much the limits but 'trend' (direction) of lightspeed I
would like to know (if it changes at all).
From the current reference frame.
:-)

David has already mentioned this. There are
limits on the change of alpha which are very
small, basically no detectable change in
billions of years. However, c could change as
long as other parameters do so in step. Your
problem then is to see whether those other
changes would affect say spectral lines in
such a way that the combination results in
the observed red shift. That won't be so easy
but essentially you have to come up with
proposed combinations of change and test them.

George
Yes, been busy, but was thinking about this.
It seems to me that if the propagation speed of the light changed,
and we know frequency x wavelength = speed, and we know there is
some redshift, that then the wavelength must have changed.
This is trcky, I will try to explain why:
If they measured wavelength with a grating, took c for constant,
and found longer wavelength for light from early universe, they
could deduce redshift.
But if they measured *frequency* ... no they could not have, because
that would violate the formula!

On the ball Jan. However, there is another aspect.
If the physical process that produces the light
defines trhe frequency, then the wavelength in
the past would differ for the same reason. If it
is the wavelength that is defined physically then
it would be th frequency that changed.

I think they MUST have measured with a grating!
See this is the fun part, there are these 3 variables, and these are
related....
Only way I see I could measure frequency (of light) is to mix it with a
known light monochromatic source and use the differece frequency,
hopefully
in the radio range.... Not sure they did that, not sure anybody did that.

The technique uses a laser as the reference and
measures the beat exactly as you say. I know the
technique has been used but I'm not sure if it
has been applied to high redshift objects. If so
I expect the would use a grating approach to get
a rough value and then use the laser to look at
a small region in hgher detail.

So, anyways things seem to figure if that redshift was measured as
wavelenght.
Very tricky to deduce one from the other, so now I will read David's post.

Lots to consider.

George

In article 1128540488.60e7d7554f18e0cdcd2f8823733fc4d5@teran ews,
Jan Panteltje writes:
If they measured wavelength with a grating, took c for constant,
and found longer wavelength for light from early universe, they
could deduce redshift.
But if they measured *frequency* ... no they could not have, because
that would violate the formula!

I haven't been following this thread, but perhaps it will be helpful
to explain that optical spectra of distant galaxies are made with
gratings and measure wavelengths, while radio spectra are made with
electronic filters and measure frequencies. Optical and 21-cm (and
CO) redshifts agree for galaxies where both have been made.

Based on a talk given here last week (and my perhaps faulty memory
and understanding), there have apparently been claims of positive
detections of a change in alpha, but no positive measurement is
sufficiently free of systematic error to be widely accepted. There
are also measurements giving upper limits inconsistent with the
claimed detections. Claimed detections and upper limits are at the
level of E-14 per year; variations at the level of E-13 per year seem
clearly ruled out. (Simple theories would predict variations of
order E-10 per year, incompatible with the data.)

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
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