First, it appears that this gets rid of the cosmological constant (which some people seem to have an aesthetic aversion to, but there's no reason it shouldn't exist) by replacing it with 'both a varying gravitational “constant” and a varying speed of light'. In other words, it appears to make the model more complicated and less aesthetically pleasing. Skimming the article, the author appears to make a fairly arbitrary seeming argument about how those constants ought to vary with time which simplifies things a bit, but it's still more complicated than traditional GR with a constant c and G.
It's not clear to me how this model purports to solve the flatness problem. There just seems to be an assertion that because the model predicts a 3-sphere geometry that the flatness problem is moot, but that seems to dodge the question. The whole point of the flatness problem is that space appears to be flat, and not a 3-sphere or hyperbolic. If you say it's a 3-sphere, the problem becomes why the universe ought to be so big that the curvature isn't apparent.
Similarly, the claim to solve the horizon problem is unsatisfying. Most attempts to explain the horizon problem require you to assume that the universe was once much, much smaller and expanded very rapidly at some point (inflation). This model appears to give you a knob to do that (variable speed of light), but doesn't really say why it should have evolved in that way.
Finally, there are some red flags to be had here from observing that the author works in the statistics department, appears to have never published any previous physics research, and in 5 months has not gotten this paper published in a peer reviewed journal and has not been cited by any other work.
Bottom line: I wouldn't put much weight on this.
irks me a little. Einstein was an unpublished patents clerk with a rocky academic record when he developed and published the special theory of relativity.
While prior publishing success and citations is undoubtedly a marker of good thinking, it is erroneous, in my opinion, to exclude the work of someone based of the fact they haven't. Because there are many, many precedents where prevoiusly unknown people have published groundbreaking work. I think everyone should be judged on the merits of their thinking, not on their status within academia.
Which is what the preceding 3 paragraphs of my comment were about. And I said it was a red flag, not a reason to outright reject the paper. While there are a few cases of outsiders making significant breakthroughs, it's rare. It's far more common for outsiders to produce work with elementary errors, which is what appears to be happening here (see the dissection at http://badphysics.wordpress.com/2010/07/28/nobang/).
Also, for the record, Einstein was not unpublished prior to his SR paper: http://en.wikipedia.org/wiki/List_of_scientific_publications...)
Einstein had a physics qualification, a teaching diploma and had several published papers to his name before he became a patent clerk. He became a patent clerk because he was unable to find a position teaching physics. A few years later he was awarded his PhD. He published the theory of relativity while he was a full-time academic.
Amateur Einsteins are the "SEO experts" of physics.
There is this perpetuating religious dogma in physics that physicists are uncovering the "elegant" rules of god, rather than creating models that match their observations. Models make predictions, and although they do reveal some things about the nature of reality, they surely do not define what it is. The next model might define it to be something completely different. Yes, we generally find that most physical phenomena can be very elegantly modeled, but that does not make a simple model better than a complex model that matches observation better.
> that does not make a simple model better than a complex model that matches observation better
Perhaps this is less of an issue in physics than some other fields because the observations are less noisy (?) -- but if getting the best match for existing observations is all you care about from a model, you could end up with something grossly over-fitted. I guess it goes without saying that any proposed physical laws need to pass the equivalent of cross-validation :)
I vaguely remember stories of this in a black hole. The "metric" changes. It involves the space dimension becoming time-like (restricted to movement forward) while the time dimension becomes space-like (finite). I don't remember the physical interpretations making much sense either.
All collected data had come to a final end. Nothing was left to be collected.
But all collected data had yet to be completely correlated and put together in all possible relationships.
A timeless interval was spent in doing that.
And it came to pass that AC learned how to reverse the direction of entropy.
But there was now no man to whom AC might give the answer of the last question. No matter. The answer -- by demonstration -- would take care of that, too.
For another timeless interval, AC thought how best to do this. Carefully, AC organized the program.
The consciousness of AC encompassed all of what had once been a Universe and brooded over what was now Chaos. Step by step, it must be done."
And AC said, "LET THERE BE LIGHT!"
And there was light----
The idea is worth exploring, but don't expect it to overturn the existing orthodoxy overnight. Particularly given that we don't actually have a physical model for how parameters can be tuned, and previous attempts to find evidence of variation in fundamental physical parameters over time have so far failed to find such variation. (See http://thefutureofthings.com/news/1254/proton-electron-mass-... for an example.)
From John Barrow:
"[An] important lesson we learn from the way that pure numbers like α define the world is what it really means for worlds to be different. The pure number we call the fine structure constant and denote by α is a combination of the electron charge, e, the speed of light, c, and Planck's constant, h. At first we might be tempted to think that a world in which the speed of light was slower would be a different world. But this would be a mistake. If c, h, and e were all changed so that the values they have in metric (or any other) units were different when we looked them up in our tables of physical constants, but the value of α remained the same, this new world would be observationally indistinguishable from our world. The only thing that counts in the definition of worlds are the values of the dimensionless constants of Nature. If all masses were doubled in value [including the Planck mass mP] you cannot tell because all the pure numbers defined by the ratios of any pair of masses are unchanged."
Quick plug: Probably the most public proponent of VSL is João Magueijo who wrote a really interesting book on the process of challenging the scientific orthodoxy, called "Faster Than the Speed of Light." It's an interesting (and often scathing) view of the process of academic science.
Later on, it goes on
"Mass and length are also interchangeable... Basically, as the universe expands, time is converted into space, and mass is converted into length."
How do you convert length into mass? The length of what?
The speed of light also controls the mass-energy conversion. So if you slow down light, then mass now has less energy.
Less energy means less gravity, and an entire cascade of related effects.
You can read some of the funnier details at [2].
