Comment by kscaldef | Hacker News Reader

Comment by kscaldef | Hacker News Reader

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.

Bottom line: I wouldn't put much weight on this.

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 Einstein was an unpublished patents clerk with a rocky academic record when he developed and published the special theory of relativity.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/).

Also, for the record, Einstein was not unpublished prior to his SR paper: http://en.wikipedia.org/wiki/List_of_scientific_publications...)

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.

> 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.

> 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.

Except that in all cases so far, the correct model turned out to be exceedingly simple.

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 :)

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