Can physical constants be different in other galaxies?

[Gerenuk]

TL;DR Summary

Please suggest references which support or make it unlikely that physical constants can change in space

I've learned that some cosmological observations do not match with theoretical predictions leading to the hypothesis of dark matter or dark energy.

Do you know references which discuss if instead the explanation could be that physical constants slowly vary in space? This seems conceptually simpler than suggesting new particles or alternative physical laws.

For example, is there a method which can measure the fine structure constant or the electron mass of matter in a very distant galaxy? This would disprove changing physical constants.

Or is there a calculation which could numerically explain observed discrepancies to theory by hypothesizing a deviation in physical constants? This would support the possibility of changing physical constants.

 

[PeterDonis]

This seems conceptually simpler than suggesting new particles or alternative physical laws.

No, it isn't, because our current physical laws do not include the possibility of physical constants varying. So any such variation would be changing our physical laws.

 

[strangerep]

TL;DR Summary: Please suggest references which support or make it unlikely that physical constants can change in space

I've learned that some cosmological observations do not match with theoretical predictions leading to the hypothesis of dark matter or dark energy.

If you're going to talk about dark matter, you should probably include galactic dynamics in your thinking, not just cosmology.

Do you know references which discuss if instead the explanation could be that physical constants slowly vary in space? This seems conceptually simpler than suggesting new particles or alternative physical laws.

...but it's obviously a total dead end (which is probably why you're unlikely to find reputable papers on such a subject).

Why is it so obviously a dead end? Give me 1 (just 1) example of a physical constant whose value you could change such that Kepler's 3rd law (orbital radius cubed $\propto$ orbital period squared) morphs into (orbital radius $\propto$ orbital period), such that the change occurs continuously as orbital acceleration decreases. [This observation is the basis of why MOND phenomenology is so puzzlingly successful.]

 

[PeroK]

Do you know references which discuss if instead the explanation could be that physical constants slowly vary in space? This seems conceptually simpler than suggesting new particles or alternative physical laws.

Galaxies everywhere (in every direction) appear to follow the same laws of physics, from galaxy formation and dynamics to star spectroscopy. This has led to the observationally-based assumption that the universe (observable universe at least) is isotropic and homogeneneous.

If the observable universe were not isotropic or not homogeneous, then we would observe the differences over time and/or space. And this would be part of established physics.

 

[topsquark]

TL;DR Summary:
Do you know references which discuss if instead the explanation could be that physical constants slowly vary in space? This seems conceptually simpler than suggesting new particles or alternative physical laws.

I agree that it would make more sense to make the assumption that there are slightly different laws at each point in the Universe rather than to "make up" new particles. However there is a principle (I forget the name of it at the moment) that says that the laws of Physics are the same everywhere and it has been in use for centuries, if not millennia. The reason is that we can't actually get out there to do the measurements. Without being able to do that it is difficult to prove this assertion one way or the other.

On the other hand, we know that many of the features of the Universe do seem to follow the same laws. Spectral images of galaxies, for example, suggests that our understanding of how atomic spectra works anywhere. There are other examples. So it is a reasonable assumption that everything is the same everywhere.

-Dan

 

[PeroK]

I agree that it would make more sense to make the assumption that there are slightly different laws at each point in the Universe rather than to "make up" new particles. However there is a principle (I forget the name of it at the moment) that says that the laws of Physics are the same everywhere and it has been in use for centuries, if not millennia. The reason is that we can't actually get out there to do the measurements. Without being able to do that it is difficult to prove this assertion one way or the other.

On the other hand, we know that many of the features of the Universe do seem to follow the same laws. Spectral images of galaxies, for example, suggests that our understanding of how atomic spectra works anywhere. There are other examples. So it is a reasonable assumption that everything is the same everywhere.

-Dan

Well, the original assumption was that there were different laws for Earth and for the heavens. So, the idea of universal laws of nature is one that was adopted through experimental evidence. The cosmological principle is somewhat stronger as it states the amount of stuff on the universe is evenly distributed on the largest scales. That also is based on experimental evidence.

Models which attempt to explain observed phenomena through changes in the laws of physics over space and time generally do not explain the observational evidence. It's not that such models are not considered as a matter of principle.

 

[Gerenuk]

I agree that it would make more sense to make the assumption that there are slightly different laws at each point in the Universe rather than to "make up" new particles. However there is a principle (I forget the name of it at the moment) that says that the laws of Physics are the same everywhere and it has been in use for centuries, if not millennia. The reason is that we can't actually get out there to do the measurements. Without being able to do that it is difficult to prove this assertion one way or the other.

On the other hand, we know that many of the features of the Universe do seem to follow the same laws. Spectral images of galaxies, for example, suggests that our understanding of how atomic spectra works anywhere. There are other examples. So it is a reasonable assumption that everything is the same everywhere.

Actually, letting physical constants vary is not a new law of physics. It's using the same laws, but for changing constants. The mass of the electron was measured on Earth and it is not determined by laws. The question is whether the mass of the electron can be measured in other galaxies through astronomical observations.

Do these spectral images you mention allow to conclude that the fine structure constant and electron mass are identical and not slightly different?

 

[topsquark]

Actually, letting physical constants vary is not a new law of physics. It's using the same laws, but for changing constants. The mass of the electron was measured on Earth and it is not determined by laws. The question is whether the mass of the electron can be measured in other galaxies through astronomical observations.

Do these spectral images you mention allow to conclude that the fine structure constant and electron mass are identical and not slightly different?

So far as I know the spectrums for hydrogen and helium (probably many others, you'd have to check with an Astronomer) are identical to those that you'd find on Earth, just redshifted. So yes, the fine structure constant and the mass of the electron should be the same.

-Dan

 

[hutchphd]

Is the OP cognizant of Dirac's "Large Number Hypothesis?" Worth a look.

 

[PeroK]

Actually, letting physical constants vary is not a new law of physics.

It would require a radical reworking of QFT and the physics of elementary particles. Not to mention the impact on GR and the nature of spacetime.

It's not a question of having a different fine structure constant. It's a question of having a variable fine structure constant. The latter would be a fundamental change to the laws of physics.

 

[PeterDonis]

letting physical constants vary is not a new law of physics. It's using the same laws, but for changing constants.

This is not correct. The fact that our current laws do not derive from first principles the values of all the constants does not mean those laws allow those constants to vary. They're still constants. If the laws allowed them to vary in space and time, the laws would be different, because they would have to include extra terms in the equations describing the space and time variations of the constants. But they don't.

 

[Gerenuk]

So far as I know the spectrums for hydrogen and helium (probably many others, you'd have to check with an Astronomer) are identical to those that you'd find on Earth, just redshifted. So yes, the fine structure constant and the mass of the electron should be the same.

I do assume they are the same. But is the resolution good enough to detect say 0.1% change in the fine-structure constant? I'm looking for a scientific answer. Someone could have stated the bound on the fine-structure constant derived from galactic light.

 

[256bits]

I do assume they are the same. But is the resolution good enough to detect say 0.1% change in the fine-structure constant? I'm looking for a scientific answer. Someone could have stated the bound on the fine-structure constant derived from galactic light.

We typically measure the fine-structure constant, α, at today’s negligibly low energies, where it has a value that is equal to 1/137.0359991, with an uncertainty of ~1 in the final digit.
https://bigthink.com/starts-with-a-bang/fundamental-physics-constants-not-constant/

although, you will find the fine structure constant does 'scale' with energy of the interacting particles.
The 1/137 that you see most often quoted is for the electron.
For heavier particles ie higher energy , one can get something like 1/128.
BUT, that is NOT a change through time nor space, AND it does fit quite well with present day theory of interactions.
You could find some more information by some googling.

 

[Vanadium 50]

But is the resolution good enough to detect say 0.1% change in the fine-structure constant?

We could see about a 10^-5 effect. This is limited by the stretching of emulsion (photographic film) during handling or thermal expansion of your spectrometer. 0,1% is 100x larger. We would know for sure.

 

[Gerenuk]

We could see about a 10^-5 effect. This is limited by the stretching of emulsion (photographic film) during handling or thermal expansion of your spectrometer. 0,1% is 100x larger. We would know for sure.

Could you provide a reference which explains how the fine-structure constant of distant galaxies can be measured with this precision through data from telescopes?

 

[renormalize]

Could you provide a reference which explains how the fine-structure constant of distant galaxies can be measured with this precision through data from telescopes?

Four direct measurements of the fine-structure constant 13 billion years ago
Michael R. Wilczynska et. al.
Abstract: Observations of the redshift z=7.085 quasar J1120+0641 have been used to search for variations of the fine structure constant, alpha, over the redshift range 5.5 to 7.1. Observations at z=7.1 probe the physics of the universe when it was only 0.8 billion years old. These are the most distant direct measurements of alpha to date and the first measurements made with a near-IR spectrograph. A new AI analysis method has been employed. Four measurements from the X-SHOOTER spectrograph on the European Southern Observatory's Very Large Telescope (VLT) directly constrain any changes in alpha relative to the value measured on Earth (alpha_0). The weighted mean strength of the electromagnetic force over this redshift range in this location in the universe is da/a = (alpha_z - alpha_0)/alpha_0 = (-2.18 +/- 7.27) X 10^{-5}, i.e. we find no evidence for a temporal change from the 4 new very high redshift measurements. When the 4 new measurements are combined with a large existing sample of lower redshift measurements, a new limit on possible spatial variation of da/a is marginally preferred over a no-variation model at the 3.7 sigma level.
Submitted 17 March, 2020; originally announced March 2020.
Comments: Accepted for publication in Science Advances
https://arxiv.org/abs/2003.07627

 

[Gerenuk]

Four direct measurements of the fine-structure constant 13 billion years ago
Michael R. Wilczynska et. al.
Abstract: Observations of the redshift z=7.085 quasar J1120+0641 have been used to search for variations of the fine structure constant, alpha, over the redshift range 5.5 to 7.1. Observations at z=7.1 probe the physics of the universe when it was only 0.8 billion years old. These are the most distant direct measurements of alpha to date and the first measurements made with a near-IR spectrograph. A new AI analysis method has been employed. Four measurements from the X-SHOOTER spectrograph on the European Southern Observatory's Very Large Telescope (VLT) directly constrain any changes in alpha relative to the value measured on Earth (alpha_0). The weighted mean strength of the electromagnetic force over this redshift range in this location in the universe is da/a = (alpha_z - alpha_0)/alpha_0 = (-2.18 +/- 7.27) X 10^{-5}, i.e. we find no evidence for a temporal change from the 4 new very high redshift measurements. When the 4 new measurements are combined with a large existing sample of lower redshift measurements, a new limit on possible spatial variation of da/a is marginally preferred over a no-variation model at the 3.7 sigma level.
Submitted 17 March, 2020; originally announced March 2020.
Comments: Accepted for publication in Science Advances
https://arxiv.org/abs/2003.07627

Thanks a lot! That's information I have been looking for. I don't have the knowledge to understand the details. The little drawback of this publication is that it says "new AI analysis method". I work in AI. "AI analysis" usually stands for "obscured BS that was invented to confirm what I want". I would have liked to see conventional statistics. But maybe I find more publications from the references. I wasn't aware that it could be measured.

 

[PeroK]

Thanks a lot! That's information I have been looking for. I don't have the knowledge to understand the details. The little drawback of this publication is that it says "new AI analysis method". I work in AI. "AI analysis" usually stands for "obscured BS that was invented to confirm what I want". I would have liked to see conventional statistics. But maybe I find more publications from the references. I wasn't aware that it could be measured.

I had the feeling you would find an excuse to doubt or reject any data you were given.

 

[BWV]

You would also need to explain what happens when two galaxies with different constants merge

 

[Conn_coord]

[Moderator's note: post edited to remove off topic content.]

Although Paul Dirac tried to justify the change in the gravitational constant.
John K. Webb has been studying variations in the fine structure constant for two decades.
Professor of Astrophysics at the Department of Astrophysics and Optics at The University of New South Wales.
Now professor of Astrophysics Cambridge University, Cambridge, England, United Kingdom

 

[Conn_coord]

It's not, it's just some people (you?) do not want to understand that professionals think this is very unlikely.

As of 2018, R∞ and electron spin g-factor are the most accurately measured physical constants.
https://en.wikipedia.org/wiki/Rydberg_constant

1998 R∞ = 10 973 731.568 549 (83) m^-1
2002 R∞ = 10 973 731.568 525 (73) m^-1
2006 R∞ = 10 973 731.568 527 (73) m^-1
2010 R∞ = 10 973 731.568 539 (55) m^-1
2014 R∞ = 10 973 731.568 508 (65) m^-1
2018 R∞ = 10 973 731.568 160 (21) m^-1
https://physics.nist.gov/cuu/Constants/

What happened?

 

[Motore]

What happened?

I guess the revision of the SI units with exact values for some constants (Planck, Boltzman, ...)
See:
https://arxiv.org/ftp/arxiv/papers/1512/1512.03668.pdf
https://www.nist.gov/publications/codata-recommended-values-fundamental-physical-constants-2018

So no, no variation of fundamental constants actually observed.

 

[Conn_coord]

I guess the revision of the SI units with exact values for some constants (Planck, Boltzman, ...)
See:
https://arxiv.org/ftp/arxiv/papers/1512/1512.03668.pdf
https://www.nist.gov/publications/codata-recommended-values-fundamental-physical-constants-2018

So no, no variation of fundamental constants actually observed.

Let`s look at the data for 2022.
Will there be any problems associated with fixing the value of Planck's constant?

DEADLINE NOTICE The 2022 CODATA adjustment of the fundamental constants is the next regularly scheduled adjustment. Data being used in this adjustment is required to have been discussed in a publication preprint or a publication prior to 31 December 2022.

 

[Cepatiti]

In the past, I came across the paper by Webb et al., "Indications of a spatial variation of the fine structure constant", published in Phys. Rev. Lett., 107, 191101, 2011, that seems to report the observation of a spatial variation of the fine structure constant, using the Keck observatory in Hawaii and the Very Large Telescope in Chili. The variation seems to fit a dipole distribution in the sky.
However, the paper is from 2011, and I did not follow their research. Hence, I do not know whether their result in the mean time has been confirmed by other research groups or not.

 

[PeterDonis]

the paper is from 2011, and I did not follow their research. Hence, I do not know whether their result in the mean time has been confirmed by other research groups or not.

Here are some relevant papers.

The Webb paper (arxiv preprint):

https://arxiv.org/abs/1008.3907

A later paper evaluating Webb's work in the light of more recent data as of 2016:

https://arxiv.org/abs/1603.04498

A 2020 paper proposing a different method of looking for possible variation of the fine structure constant and evaluating constraints on such variation from data using that method:

https://arxiv.org/abs/2004.08484

A 2022 paper proposing a theoretical model for possible variation in the fine structure constant and evaluating it against data:

https://arxiv.org/abs/2207.03258

I would say the takeaway from all of this is that some researchers think the data show some (very small) variation in the fine structure constant over time in our universe, while others don't, and nobody has a theoretical model that (a) predicts such variation and (b) matches the data.

 

[Vanadium 50]

John K. Webb has been studying variations in the fine structure constant for two decades.

"Looking for" and "finding" are two different things.

 

[Vanadium 50]

some researchers think the data show some (very small) variation in the fine structure constant

I'm going to disagree. The word they used was "indications" and not a stronger word like "evidence" or "observation". They had to publish what they saw, but what they saw is not particularly convincing,

Let's look at Webb's data:

First fact - the whole effect is driven by two points. Remove the first and last points and nobody would say there is any evidence of anything.

Point ordering is determined relative to the best fit dipole. The fact that the two most extreme points are at the opposite ends of the plot is, at least partially, how they are defined.

Second fact - the scale is about the same as the systematic error of the individual measurements, 10^-5. So this is right at the edge of detectability. Some would say past it.

Third fact - this curve does not go through the origin, as it must by construction. The so-called monopole term $m$, discussed in [6] suggests they have a measurement systematic of order $m\sqrt{N}$ or about 0.7 x 10^-5, more or less in agreement with my prior argument

Fourth fact = the "4.2σ" signal is the degree the best fit differs from zero. It is not (nor can it easily be converted to) a P-value. They pick the most significant dipole fit and quote how different the amplitude is from zero. That is a perfectly good number, but is not a P-value, nor is it even distributed normally with mean zero.

A very, very rough estimate of mine is that with no effect you would see an average maximum deviation from zero of 3.3σ and 4.2σ or more 12% of the time. This is not a proper statistical analysis, just intended to show whether it was one in 8 or one in 8 million.

Webb (who I only met once) is a smart guy and Flambaum (co-author, who I have interacted with several times) is a very smart guy. They know this. And that's surely why the title is what it is and they are not packing for a trip to Stockholm any time soon.