If I am understanding this right, the idea is that the red shift of distant astronomical objects might not be caused by the Doppler effect due to things moving away from us, but by an increase over time in the mass of electrons and other subatomic particles. This means that the spectral emission lines of atoms would also change over time, becoming steadily bluer. (I did not know that spectral lines depended on electron mass, but maybe they do.) So, when we look at things many light years away, we are seeing them before their emission lines became as blue as the ones we see from matter close to us. Traditionally that has been interpreted as a red shift due to recession velocity, but it could be that distant things are not consistently receding at all, rather, spectral have got bluer here since the time the distant light was emitted.
To the physicists here: does this actually make sense? If so, how come no-one has thought of it before? It seems such a simple alternative explanation (even if I have not succeeded in explaining it very clearly).
Um. no, unless you can explain how mass increases in just such a way as to mimic the (very well documented) Doppler effect. Until then the most parsimonious explanation will be that the spectrum looks Doppler shifted because it is Doppler shifted.
Does the mass have to do anything but increase steadily with time? That would surely give an apparent red shift identical to what you would see from steady expansion of space with time. The specific rate of expansion or mass increase is, in either case, an empirical matter which we measure from observing the actual red shift. The question is whether you explain the observed correlation of red shift with distance in terms of expansion and the Doppler effect or in terms of mass increase and whatever mechanism links particle mass to emission line frequency.
The weak link, if there is one, seems to me to be in the link between mass and line frequency. Is there a known connection there? It is news to me.
Well, as no change in the mass of an electron (of AFAIK any other particle) has ever been observed, and this hypothetical mass increase seems to be just a finagle factor to offer an alternative to expansion, I cannot answer that question.
Perhaps one of our members who understands the math could plug a higher value for electron mass into whatever equation defines spectral emission lines and tell us if it is bullshit.
I could believe the spectrum for an atom where the constituents were less could look like qualitatively it was red-shifted. I’d have a harder time believing that the shift would look exactly the same for all spectrum lines in all atoms. But I don’t have time to read the associated paper, to see if they cover that.
I have no idea whether the non-expanding universe idea is bullshit or not, but if it is true it wouldn’t rule out the possibility that some galaxies are indeed moving toward or away from us.
This is actually an old idea due to Fred Hoyle. I heard him give a talk on it. He was still trying to find an alternative to the big bang (incidentally, he created the term–it was intended as a put-down). He went through the details and ended up by saying that the theory could not be distinguished by any data, was in fact equivalent. So what’s the big deal.
Obviously, Andromeda’s blue shift is a Doppler shift. Hoyle never suggested that the Doppler effect wasn’t real, only that the cosmological red shift is due to this change in mass. If two theories are equivalent, then you can choose the one that pleases you.
This new theory posits red and blue doppler shifting exists. And anywhere and everywhere you measure a red and blue doppler shift it’s because of relative movement away or toward you except in one case: very far galaxies.
Now mind you, in principal, the idea that “space is expanding everywhere” is just as mind-blowing as the theory “mass is getting more massive everywhere.” But one fits the set of data better than the other.
The cosmic red shift is NOT a Doppler shift. It’s not caused by the emitter having a high recessional velocity, but rather by the metric expansion of space as the light makes its way to earth.
It seems like an increase in mass should have other effects besides an increase in the wavelength of emitted light. For example, if distant galaxies are more massive, that should also show up as a difference in rotation speed.
The author of the paper referenced in the article in the OP never shows that there would be no changes in the spectrum of atomic transitions, he sort of hand waves it, and references COSMOLOGY AND THE FATE OF DILATATION SYMMETRY, by C. Wetterich (PDF). I can’t really follow that paper. He mostly discusses Cosmology, but states
I’m not sure whether that is supposed to be generally true throughout the paper, though.
Thanks for mentioning Hoyle. It reminded me of a youtube conversion between Hoyle and Richard Feynman where they discuss their two different approaches to theoretic problems. Feynman is very conservative with regard to tearing down physical laws to investigate alternatives because once you start, there are so many different ways changes to laws you could investigate and how do you know you’re investigating the right one.
Hoyle, on the other hand, doesn’t care if he’s investigating the right change as long as he finds it interesting. There may still be something to be learned from chasing down a blind alley for a while. Make him sound less flaky and more … um … something else.
I suspect something similar is going on here. The increasing mass theory might be true but I think it’s almost certainly not. Nevertheless, is there a chance that some valuable insight could come out of studying a “what if” like this and I wonder if that’s the real reason.
That said, I know so little about this that my intuition might be wrong and this theory could be reasonable in its own right for all I know.
I also heard Hoyle talk about a variant of this theory. That was in the 1970’s. I must admit that Hoyle’s talk was largely incomprehensible to me.
People have done very precise experiments looking for changes in the fundamental constants, for example by comparing clocks built with microwave cavities to clocks made with atomic oscillators. These experiments were sensitive enough to see changes on a cosmological time scale (for example drift of 1/(age of universe)). No cosmological drift has ever been detected.
According to Hoyle (read my post), there are no observable differences between the two theories. The both fit observed data just as well. If there are later observations that contradict this, please cite.
Is there a cite that there are no observable differences? Did Hoyle publish this in a paper? (Or maybe the paper I linked to is that cite. I don’t think it is, but like I said, I couldn’t really follow it.)
This assertion was not made (to the best of my recollection) in the talk I heard by Hoyle. He made a point of talking about surfaces in spacetime that correspond to the big bang origin and referred to more complex possibilities than in the standard model (which at that time did not include inflation or a cosmological constant). As I mentioned though, I did not understand his argument, so my memory is not necessarily to be trusted.
In that respect it is just the same as the “old” theory that the red shift of far away galaxies is caused by expansion. [I take it that that is what you mean to be saying, but it isn’t altogether clear to me.]
Well does it? In what way? That is my question, really. Are there any independently established facts that the expansion theory explains and that this mass increase theory does not?
Presumably in Hoyle’s version the problem was that he could not explain the microwave background, but this guy may have allowed for that, as he does not seem to deny that there was a big bang:
I have to admit I do not really understand what is being claimed there, but then I never could understand the whole “inflation” thing.
Hoyle’s variable mass theory was conceived at a time when there were considerably less detailed observations than there are now and is primarily used as an alternative explanation of cosmological redshift. Since then it has been shoe-horned into some non-standard cosmologies outside of big bang theory. As a general rule these non-standard cosmologies have failed to fit observations as well as the big bang theory.
This new model though is considerably different to those non-standard cosmologies which tend to utilize Hoyle’s variable mass theory and is more like a scalar-tensor theory of gravity and very similar to Brans-Dicke theory. (which is one of the most popular alternatives to general relativity as a relativistic theory of gravity).
To explain: Einstein’s field equations, which can be written as a rank 2 tensor field equation, describes gravity in general relativity. Inserting an additional scalar field (rank 0 tensor field) into the equations governing the dynamics of spacetime allows for theories where general relativity becomes merely a special case of when the scalar field is allowed to assume a certain constant value. In this new model the additional scalar field describes the reduced Planck mass, which is allowed to vary strongly with time.
Such a theory can always recreate the predictions of general relativity, but the main criticism is that the additional variable can be very amenable to being tuned in order to give you whatever answer you’re looking for (or in other words they are very good for creating models that retroactively fit the data, rather than creating models that give new and different predictions). It’s worth noting though that in this new model there is a big difference in that, the region of spacetime used to describe the current era in this model, would describe an era where the Universe is actually contracting in general relativity.
In Wetterich’s model there is no spacetime singularity as the pathological behaviour doesn’t appear in the spacetime itself, but appears when you introduce spacetime coordinates that are re-scaled to describe the Universe as it appears to us (i.e. that it appears to be expanding). The reason for this that the infinite past is reached in a finite amount of coordinate time in these coordinates. Inflation and dark energy appear to be basic predictions of Wetterich’s model, rather than things that have to be added in by hand (but see what I said earlier about the highly tuneable nature of such models).
As for the connection between electron mass and spectral lines, emission spectra are described by Rydberg’s formula, within which there appears a constant, called appropriately enough Rydberg’s constant, which was first determined empirically, and later derived from quantum mechanical models of the atom, and shown to depend proportionally on the electron mass. As for the objection that one would observe different gravitational behaviour in far away, and thus old, galaxies, this need not be the case: the Planck mass is inversely related to Newton’s constant G, which gives the strength of gravity; thus, if the Planck mass grows, G must shrink, and potentially, everything works out smoothly.
Incidentally, this isn’t the only alternative explanation of the cosmological redshift; another class of models falls under the heading ‘tired light’, and concerns proposals in which light, due to some mechanism or another, looses energy more or less continually during transit, getting redder and redder in the process. I’m not sure there’s any member of that class considered to be viable today, though.
Another question I don’t know the answer to is whether the redshift is really the only indication we have regarding the universe’s expansion. Distances on a cosmological scale are typically measured using standard candles, that is, objects whose luminosity is known very accurately; by comparing this to their observed brightness, one can then directly derive their distance. Given a long enough time, one could presumably look at one such standard candle and see if it gets dimmer, i.e. recedes, in accordance with its redshift; but probably, such observations have not yet been feasible, given that the time we’ve had to make them would allow only for a minuscule change in brightness.
AFAIK there isn’t a huge amount of evidence for expansion that is independent of redshift, but there is some. In the big bang model the temperature of the CMB decreases in time, whereas in most steady-state models the CMB would be expected to have a constant temperature.