[Huxlly (OP)]

Could the fundamental constants in nature be changing to give us the illusion that the universe is expanding?

[Mr. Scientist]

It turns out that a number of physicists have proposed that the speed of light varies. The idea that the speed of light in the past cone of the universe was many multiples of c, seemed to remove many cosmological problems.

One that I can think of off the top of my head, is the time it requires to allow light to reach all four corners of the universe. In order to create a balance in the equations with observational evidence of the background temperatures, an inflationary period was introduced. This moment which allowed the universe to expand faster than light itself, allowed light to reach all four corners of the universe, and create a homogeneous background of gamma particles. If we did not have this inflationary period, we would see clumps of the background radiation showing different temperatures, but this is not the case. Immediately, one can deduct, that if light speed was many more times c, it would remove this problem, and without need of some phenomenal inflationary period that occurs around -33 and -35 seconds after big bang.

The scientists I refer to at the beginning of the post, include V.S. Troitskii [1] who proposes that the speed of light was initially 10^10 times the general speed of c, Moffat [2] who proposed it be a value which has dropped over the billions of years since big bang, Albrecht and Magueijo [3] who agreed with Moffat and proposed a whopping value of c that was 10^60 times the value of c, and John Barrow [4] who agreed with that value, who proposed it dropped over the lifetime of the cosmos, instead of proposing it be immediately after big bang.


[1]. V S Troitskii, Astrophys. & Space Science 139 (1987) 389.
[2]. J Moffat, Int. J. Mod. Phys. D 2 (1993) 351 and Int. J. Mod. Phys. D 23 (1993) 411.
[3]. A Albrecht, J Magueijo,Phys. Rev. D 59:4 (1999) 3515 .
[4]. J D Barrow, Phys. Rev. D 59:4 (1999) 043515-1.

[Vern]

There are much more simple ways to arrive at the same observables we see in the universe today. The one I like best is that light gradually loses energy over time. If different frequencies lost energy at a different rate, the universe would seem to be expanding.

[PhysBang]

Both the changing speed of light theories and the tired light theories fail for one simple reason: they cannot match the data without adding in some additional unknown factors that just happen to make the universe look just like it's expanding. And I mean really, really close.

There are a few things that go really, really badly for both theories, but I will stick with one: time dilation. If there is a change in light that is responsible for the redshift-distance relationship that is the fundamental piece of evidence for expansion, then there is no reason that this change in light should be accompanied by time dilation as predicted by general relativity. And when we can measure time dilation in very distant objects, it is exactly that which should match redshift given the standard theory of light.

For example, see Blondin, S., Davis, T. M., Krisciunas, K., Schmidt, B. P., Sollerman, J., Wood-Vasey, W. M., et al. (2008). Time Dilation in Type Ia Supernova Spectra at High Redshift. Astrophysical Journal, 682, 724-736.

(This should be available as a preprint at arxiv.org.)

[Vern]

Lyndon Ashmore has studied this and claims that it supports the tired light scheme.

When sending digital pulses down a fibre optic, monochromatic light is used as different frequencies travel at different speeds down the fibre. If white light is used, this leads to 'pulse broadening .' In supernovae 'time dilation' muticolour light curves are considered. However, a supernova burst is just a digital pulse and 'pulse broadening' is not taken into consideration when testing Tired Light models [1].

This produces an effect similar to 'Time Dilation.' Different frequencies of radiation are known to travel through space at different speeds [2] as is shown by gamma ray bursts. All frequencies may well start off at the same time but they will arrive here on Earth at different times - and the greater the redshift, the greater the pulse broadening! Who needs expansion and relativity - Tired Light.

A video here shows a supernovae event and it clearly shows the colours arriving in order.

[Bored chemist]

As you can see from the "notches" in that spectrum, there is clearly something in the way between us and the light source. It absorbs light at some wavelengths and that's why there are dips in the intensity.

As they say, if you have light traveling through a medium- whether that's an optical fibre or the interstellar gas, there will be an optical dispersion effect.
The only exception would be if there were an absolute vacuum between us and the light source.
If there were a complete vacuum the absorbtions we see in the spectrum would not be there. We see the absorbtions so we know it's not a perfect vacuum.
Since it isn't a perfect vacuum it is allowed to have an optical dispersion.
There's nothing new here. With a sensitive enough system you could show the same effect here on earth with a long tube full of water.
There's nothing here to support the so called "tired light" theory.

[Vern]

It is meant to show that the time dilation assumed for type 1A supernovas is really not time dilation but is instead a smearing of the frequencies. Time dilation would support the Big Bang scenario and an expanding universe.

BTW: The Lyman Alpha forest of which you post shows that the hydrogen clouds in the early universe were spaced about as far apart as they are in the present universe. If the universe has been expanding for a bunch of billion years shouldn't they have been closer together in the past? []

[PhysBang]

Different frequencies of radiation are known to travel through space at different speeds  as is shown by gamma ray bursts.

This is actually the opposite of what studies of gamma ray bursts have shown.

http://news.stanford.edu/news/2009/october26/fermi-telescope-discovery-102809.html

Neither is a type Ia supernova a digital burst. It is a sustained radiation emanation over 20 to 30 days from superheated material.

Nor does the video show what Lyndon Ashmore claims.

Nor is it the case that we do not observe time dilation in quasars.

Lyndon Ashmore's website is either based on gross incompetence or lies.

[Vern]

You have shown yet another report of conclusions rather than the actual experimental results. There is nothing in Einstein's theories that would have all frequencies of light propagating through space at the same speed. Different frequencies travel at different speeds through different media. Space is filled with media consisting of ions, atomic clouds, electrons, and other stuff.

I didn't see anything in the results to support a different notion. Light still shows spectra when seen through a prism.

[PhysBang]

You have shown yet another report of conclusions rather than the actual experimental results.

I'm sorry, since you posted a link to a crazy person's website, I figured that the standards here were low.

I noticed that you avoided saying anything about the actual scientific paper that I cited above, one that reacks time dilation in a far different manner than that addressed by the crazy person. I also note that you didn't address any other points.

There is nothing in Einstein's theories that would have all frequencies of light propagating through space at the same speed. Different frequencies travel at different speeds through different media. Space is filled with media consisting of ions, atomic clouds, electrons, and other stuff.

Not really. Space is really, really empty. Even galaxies are really, really empty. If you want to have a theory explaining redshift through some sort of medium, you're going to have to explain why this medium doesn't scatter the light; such theories fail because we can clearly see other galaxies that we wouldn't if there was a significant medium in the way.

And time dilation and scatter are not the only problems for tired light theories! There is also the observed acceleration of expansion. Tired light theories have to explain why light is getting more tired. And since we can see that the expansion was slowing down in the distant past, tired light theories have to explain why light was getting less tired in the past before it started to get more tired.

Or, one could junk tired light and move to a scientific explanation of the observations that not only explains them, but uses them to measure features of the universe. One of the striking feature of standard cosmology is the agreement in measurements that it produces from distant sources.

[Vern]

I noticed that you avoided saying anything about the actual scientific paper that I cited above, one that reacks time dilation in a far different manner than that addressed by the crazy person. I also note that you didn't address any other points.

I read the paper you linked; it was conclusions reached and not experimental results. You claim that Lyndon Ashmore is a crazy person? He is a working physicist; I don't know anything about his sanity; but his conclusions seem reasonable given the experimental results that he cites.

And time dilation and scatter are not the only problems for tired light theories! There is also the observed acceleration of expansion. Tired light theories have to explain why light is getting more tired. And since we can see that the expansion was slowing down in the distant past, tired light theories have to explain why light was getting less tired in the past before it started to get more tired.

It is much more simple to imagine the wave length of light being distorted by some unknown thing than to imagine the whole universe being distorted by some unknown thing.

[Bored chemist]

Re "The Lyman Alpha forest of which you post shows that the hydrogen clouds in the early universe were spaced about as far apart as they are in the present universe."

No, it doesn't. Once the hydrogens are separated by a few atomic diameters there's no way of knowing , from the spectrum., how far apaprt they are.
There's a thing called "pressure broadening" but it really doesn't amount to anything in a bloody good vacuum with a poorly defined temperature.

"re.
"It is much more simple to imagine the wave length of light being distorted by some unknown thing than to imagine the whole universe being distorted by some unknown thing.
"
It's easier still to say that the wavelengths are distorted because of a known thing.  They are moving through some medium- the interstellar gas.
We know it affects them - you can tell from the dips in the spectrum
Why not accept that it's the reason for the dispersion?

[Vern]

No, it doesn't. Once the hydrogens are separated by a few atomic diameters there's no way of knowing , from the spectrum., how far apaprt they are.
There's a thing called "pressure broadening" but it really doesn't amount to anything in a bloody good vacuum with a poorly defined temperature.

I don't guess I follow your reasoning here. [] The hydrogen line forms in the ultra violet part of the spectrum when the light moves through a hydrogen cloud. As the light continues on to the next hydrogen cloud it is red shifted by a certain amount. When it goes through the next cloud, another hydrogen line happens again in the ultra violet. This continues cloud by cloud until we finally observe the completed spectrum.

The distance between the hydrogen lines in the spectra should indicate the distance between the hydrogen clouds that the light encountered on its way to us.

Here's Wiki on it.

Since neutral hydrogen clouds at different positions between Earth and the distant light source see the photons at different wavelengths (due to the redshift), each individual cloud leaves its fingerprint as an absorption line at a different position in the spectrum as observed on Earth.

It's easier still to say that the wavelengths are distorted because of a known thing.  They are moving through some medium- the interstellar gas.
We know it affects them - you can tell from the dips in the spectrum
Why not accept that it's the reason for the dispersion?

I think I agree with that if I understand it correctly.

[litespeed]

2 Cents Worth,

Expansion of space creates red shift which is also a decrease in electromagnetic energy. That energy went someplace. My quess is it both creates and maintains space expansion itself as it moves through 'the either'. The ultimate entrophy?

If space continues to increase expansion speed, eventually all photons will approach zero frequency.

[Vern]

I kinda liked the idea of empty space as nothingness. In that case there's nothing there to stretch. It is a very restrictive scenario and demands a little thought to explain observations. If space-time is a variable, it is like trying to build a complicated structure with an elastic ruler.

However the scenario is not so restrictive that observations can not be explained within it. All observations remain intact. Most theories have to change. []

[PhysBang]

I read the paper you linked; it was conclusions reached and not experimental results.

Hunh? Blondin et al. is all about what was actually observed. Are you saying that all of astronomy is illegitmeate because one cannot do a lab experiment on a star?

You claim that Lyndon Ashmore is a crazy person? He is a working physicist; I don't know anything about his sanity; but his conclusions seem reasonable given the experimental results that he cites.

But he is either grossly wrong about the things he talks about or he is a liar. To look at just one example, how do you explain his claim that type Ia supernovae are digital pulses when they clearly last for about a month?

It is much more simple to imagine the wave length of light being distorted by some unknown thing than to imagine the whole universe being distorted by some unknown thing.

But doesn't the fact that no tired light theory actually matches the data give you pause? Doesn't the fact that it can't measure anything, but the standard model does, cause you some concern?

[Vern]

I looked through the Ashmore data several times; he didn't say anything about the light from 1A supernova being digital. He showed that different frequencies arrive at different times. In addition to that he pointed out that the absolute magnitude of more distant supernovas is less than that of closer supernovas of the same type. This supports that the light pulse is smeared over time.

While not absolutely convincing, the scheme seems plausible. Just about any thing would be more plausible than the idea that empty space can stretch. That idea tests sanity IMHO. []

I haven't signed onto any tired-light theory to the extent that I would say that is the one. Measurements work with either scheme.

I couldn't describe the Standard Model to anyone and keep a straight face. To me it is an absurd notion. The idea that space-time is variable and laws of nature only temporarily apply to the present just can't fit in my concepts. It would be embarrassing to me for people to think I signed onto the Standard Model concepts.

[Ethos]

 It would be embarrassing to me for people to think I signed onto the Standard Model concepts.

And I also have problems with it myself Vern.

Let's perform a thought experiment;

If space is simply nothingness, as I believe it to be, then measurments of distance are only abstractions relative to surrounding objects. For we humans, measurement of space itself is only a relative term. If we assume that space is expanding, where is the standard by which we guage this expansion? The notion that just because we see objects moving away from our present position in space does not necessarily confirm that space itself is expanding. To prove this expansion exists, one must find an unmovable area of space as a point of reference and this, IMHO is an impossiblity. How does one establish a point of reference in nothingness? I contend that it can't be done. To suggest that space is something is a contradiction in terms. How can one place something where something already exists? It would be like parking two cars in the same one car garage! 

[Vern]

In order to stretch space would need a property of stretchiness. If such were found and we could isolate a local area and measure the stretch property to see how much expansion had happened, I might give it more credibility. []

[PhysBang]

I looked through the Ashmore data several times; he didn't say anything about the light from 1A supernova being digital.

Then, as I suspected, you aren't really interested in how Ashmore gets to his conclusions, you simply like his conclusions.

From your link: "However, a supernova burst is just a digital pulse and 'pulse broadening' is not taken into consideration when testing Tired Light models."

He showed that different frequencies arrive at different times.

No, he did not. he provided a link to a video from a supernova research group that shows how the intensity of different frequencies differs over time. This is something that has been studied in great detail by those who study type Ia supernovae. Ashmore offers no analysis.

In addition to that he pointed out that the absolute magnitude of more distant supernovas is less than that of closer supernovas of the same type. This supports that the light pulse is smeared over time.

I can't see how he can show something that simply is not the case. He provides no argument about different brightness except for a lame "some say..." about Malmquist bias, something he gets incredibly wrong.

While not absolutely convincing, the scheme seems plausible. Just about any thing would be more plausible than the idea that empty space can stretch. That idea tests sanity IMHO. []

I'm guessing it's too late for some.

I haven't signed onto any tired-light theory to the extent that I would say that is the one. Measurements work with either scheme.

Then let's see a paper with measurements as detailed as those produced by the horde of papers out there on the standard model. Just one, please.

I couldn't describe the Standard Model to anyone and keep a straight face. To me it is an absurd notion. The idea that space-time is variable and laws of nature only temporarily apply to the present just can't fit in my concepts. It would be embarrassing to me for people to think I signed onto the Standard Model concepts.

I see that you simply do not understand the standard model. That's OK. But why do you sign on to the ravings of Ashmore rather than those of scientists who are able to truthfully represent their work and the work of others?