Based on little more than this summary of the article, it's not particularly clear to me how this solves the purported problems it's trying to address.
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.
I'm not in a position to comment much on the substance of your article, but this line:
"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."
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 Einstein was an unpublished patents clerk with a rocky academic record when he developed and published the special theory of relativity.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.
> 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/).
> Einstein was an unpublished patents clerk with a rocky academic record when he developed and published the special theory of relativity.
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.
Science is a social endeavor like all other human activity, and looking at an author's background is an amazingly efficient heuristic for detecting cranks. Relativity and cosmology seems to produce lots of them, and they--unlike Einstein--typically don't even fully understand the theories they're trying to replace.
Amateur Einsteins are the "SEO experts" of physics.
> In other words, it appears to make the model more complicated and less aesthetically pleasing.
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's true, but that statement was in the context of the desire that some people (including, it would seem, the author of the article) have to get rid of the cosmological constant. The only reasons I am aware of that anyone dislikes the cosmological constant are aesthetic. It's an extra parameter that makes things a little more complicated, but there's no a priori reason it should be zero. Thus, I assert, if one wants to get rid of it, you shouldn't be replacing it with a _more_ complicated model that's no more predictive.
Good point in that the aesthetics of a model are in the eye of the beholder - although:
> 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 :)
My summary. New class of theories with lots of tunable parameters can explain existing observation through choosing the right parameters to tune.
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.)
The class of theories is hardly even new. Dirac suggested the possibility of variation in universal constants in the 30s. In the 80s and 90s, at least three different instantiations of VSL popped up and have been getting varying amounts of press ever since.
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.
If you'll read the paper itself [1], you'll see that the author takes well known equations, replaces some constants with functions of time and tries to draw conclusions from there. In short, it's bogus.
As an academic, I would advise lay science enthusiasts to steer clear of anything classified as "general physics" (or "general mathematics") in the arXiv. There's far too much of it, mostly junk, and you'd be better spending your time elsewhere.
Relevant - "Matter and energy had ended and with it, space and time. Even AC existed only for the sake of the one last question that it had never answered from the time a half-drunken computer ten trillion years before had asked the question of a computer that was to AC far less than was a man to Man.
All other questions had been answered, and until this last question was answered also, AC might not release his consciousness.
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."
While I love reading articles about science they are almost always simplified to the point if being frustratingly meaningless. Phrases like "as the universe expands" loose all meaning when you're talking about time being converted into space. If only there was somewhere that explained the implications of what seems like this beautifully elegant idea in an equally elegant way... sigh
At the very least I wish we had a 'grellas' for space and astronomy lurking around here, just waiting to do a drive-by and drop a mega comment that answers all of our questions.
I won't hold myself out as that much of an expert - cosmology was never my specialty and I haven't been a practicing physicist for a decade - but see my comment: http://news.ycombinator.com/item?id=2006334
Wow - that post was more than I was expecting - kudos (from a complete layman).
BTW - have you ever done speaking/books on debunking / explaining physics in general? It seems like you'd be a shoe-in for a Brian Cox-type role as a more hip face of physics - though maybe you'd like to avoid that...
Correct me if I'm wrong, but seems like the idea of "time being converted into space" is itself pretty meaningless because it implies conversion happening over time.
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.
So if time, mass and length are convertible, does this mean we (the Defense Department) could theoretically (secretly) make a 'time-bomb?' Sort of like an atom bomb, except instead of releasing heat/energy, it releases a time-bubble in which, I dunno, NP problems (enemy ciphers) could be brute-force computed and solved within our lifetimes (wartimes).
Lots of things are theoretically possible. However, I'm going to bet that it would be a lot easier to just go off and find the guys with the plaintext (or keys) and hit them until they give you whatever information you want.
So if the speed of light was slowing down, since everything else seems to obey the same unknown rule, would we even know it? It would be impossible to measure the change right?
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.