Can the cosmological redshift be interpreted as atomic frequencies increasing by the scale factor as the Universe expands?

This explanation seems closer to the truth than the popular idea that a photon's wavelength somehow expands while it travels to us from a distant galaxy. Metric expansion only occurs with proper distances (between events at the same cosmological time).

I think people take the standard derivation of the cosmological redshift to imply that the photon's oscillation period increases with the scale factor. But this again is equivalent to assuming its wavelength increases.

  • $\begingroup$ Related: physics.stackexchange.com/q/2110/2451 and links therein. $\endgroup$
    – Qmechanic
    Apr 24, 2013 at 18:39
  • $\begingroup$ So I take it that you don't subscribe to the notion that as the photon travels through expanding space, more and more space is added between its crests and troughs, thus "stretching" the wavelength over time? $\endgroup$
    – Jim
    Apr 24, 2013 at 19:25
  • $\begingroup$ What do you mean by "atomic frequencies increasing"? Do you mean the energy levels in atoms are changing? $\endgroup$ Apr 24, 2013 at 19:32
  • $\begingroup$ Are you familiar with the relativistic Doppler effect? To understand what you're asking, it'd be useful to know whether or not you're familiar with this effect. $\endgroup$ Apr 24, 2013 at 19:45
  • 5
    $\begingroup$ "This explanation seems closer to the truth than [...]" Isn't really an argument, it's an expression that your notion of common sense is offended by the current theory. You are certainly welcome to that opinion, but you probably shouldn't expect it to hold much weight in physics circles. In any case, we can observe gravitational redshift in the laboratory and it shares the feature of "a photon's wavelength somehow expand[ing] while it travels". $\endgroup$ Apr 24, 2013 at 20:32

3 Answers 3


"Metric expansion only occurs with proper distances (between events at the same cosmological time)"

Why would this effect disappear when you integrate over paths in space-time (e.g. photon trajectories)?

The redshifting of light by spacetime geometry is an observational fact, not an ad hoc conjecture.

"Can the cosmological redshift be interpreted as atomic frequencies increasing by the scale factor as the Universe expands?"

No. This wouldn't explain why all sources of radiation (e.g. synchrotron, black-body, bremsstrahlung, etc) are all effected in the exact same way.


It's both effects combined.

They are not in competition.

You get a Lorentz time dilation (i.e. frequencies are slowed) from the relative motion and also the `stretching' of the wavelength (i.e. an additional decrease in frequency) due to the expansion of the Universe.

They are separate effects and they combine together.


Yes, indeed.

"cosmological redshift CAN be interpreted as atomic frequencies increasing by the scale factor as the Universe" evolves (NOT expanding).

Your statement correspond the interpretation that the 'space is not expanding' but instead the ruler (always made of atoms) shrink as time goes by, giving an apparent increase of the space. Space expansion is an observational fact and Matter-shrinking (evanescence of matter) is the cause. Naturally this fact can not be detected in the lab but looking for 'old' atoms far away we see that they have bigger dimensions (length, mass and time unit) than the ones that surround us. For the same atomic process the actual/local emited wavelength is shorter, blue-shifted, in relation to the past emission.

This novel model was NEVER discussed (Nobody has presented an argument against this view) it was first presented here:
A relativistic time variation of matter/space fits both local and cosmic data (arxiv)

and a complete formal presentation was done here (with my modest contribution):
A self-similar model of the Universe unveils the nature of dark energy (pdf).

Until now the general equations of physics are only expressed in terms of 'Atomic Units', based in local atomic properties. In that paper we learn how to express them in terms of 'Comoving coordinates', were the observer is above the restrictions of beeing attached to the ruler, that make us blind to any matter properties variation.

Changing the perspective is somehow a question of 'relativity' (not the motion one). In the matter/space relationship I chose to analyse from the 'space' perspective instead of the 'matter' one. Some surprises: The Dark Energy (to accelerate expansion), the Cosmological Constant (to nullify the expected gravitational contraction of the universe), the Inflation phase (to make it homogeneous) are artifacts of BBT theory. Simply they are not needed. If the 'Occan Razor' can be used, and should be, we must choose this new approach.

Once more I expect to be downvoted and I will not expect to see a single argument against the theory. The BBT is a dogma because everybody already knows that is is true that space is expanding. To a formal theoric paper it is expectable that someone, sometime, will take the time to read it.


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