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I found this fascinating story The Fundamental Constants Behind Our Universe at medium.com's "Starts with a Bang" column. Ethan Siegel posits:
But the Universe itself experiences continual growth, constant change, and new experiences all the time, and it does so spontaneously.
And yet, the better we understand our Universe — what the laws are that govern it, what particles inhabit it, and what it looked/behaved like farther and farther back in the distant past — the more inevitable it appears that it would look just as it appears.
[...] We’d like to describe our Universe as simply as possible; one of the goals of science is to describe nature in the simplest terms possible, but no simpler. How many of these does it take, as far as we understand our Universe today, to completely describe the particles, interactions, and laws of our Universe?
The answer? "Quite a few, surprisingly: 26, at the very least." He then goes on to explore what these are and how they are computed.
Sadly, we don't know enough to be able to predict everything. As the article notes, there remain problems with explaining CP violations, matter-antimatter asymmetry in our Universe, cosmic inflation, and what dark matter actually is.
Separately, but related: many years ago I came upon a site that provided interactive exploration of the scale of things in the universe from Planck length on up to the the visible universe. (And, no, it was not powersof10.com) I have a niece who is curious about such things and I would love to share such a site with her. Sadly, I can no longer locate a link. Any suggestions?
(Score: 5, Insightful) by boristhespider on Sunday February 08 2015, @07:05PM
"Has this theory been dismissed?"
No.
What you're faintly remembering is the unification of forces. There are four known forces that are held to be fundamental -- gravity, the electromagnetic force, the weak nuclear and the strong nuclear forces. The electrical and magnetic forces are unified at all energy scales. This is very clear when you phrase it relativistically; the easiest way of dealing with electric and magnetic fields is to absorb them into a single object (known as the "Faraday tensor" -- at rest in a flat spacetime, it's effectively a matrix with time and space along both axes, with the diagonal zero, the three components of the electric field along the time line, and then the three components of the magnetic field filling in the remaining triangle). This object is the same in every coordinate system, for any observer. What changes are how much of the Faraday tensor lies along the observer's "time", and what lies perpendicular to it.
In relativity, we don't have a clear time coordinate, which is one of the fundamental tenets of the theory. Instead we can pick any "timelike" vector, which means one that's basically pointing at the future, and treat that as a time. The most immediate of those is the (4-)velocity of an observer. Using the 4-velocity to define a time, we then have a three-dimensional space perpendicular to it, like a field with a single mast sticking up in the middle of it. If one takes the Faraday tensor, which is itself the same in every coordinate system, the electric field is that part of the Faraday tensor that lies along the 4-velocity (phrased a different way, the electric field is the Faraday tensor projected along the 4-velocity). The magnetic field is extracted in a slightly more complicated way from the remaining parts.
At the level of quantum mechanics, electromagnetism is described by the exchange of "virtual" photons -- electrically-charged objects transfer these constantly, and the coupling of the objects to the photons determines the force. This formalism also relies intrinsically on the relativistic description, and is very well-defined once you accept the apparent ridiculousness of renormalising, when you say, effectively, "Well, there's this infinite sum here, right, multiplying an electron mass, right, so all I do, right, is say that that's a *bare* electron mass and that, right, the product of the infinite sum and the bare mass is the observed mass! Et voila, no infinities!" Sounds daft, and I believe it was Schwinger but it may have been Feynman who in the early days of quantum electrodynamics commented that they had profound doubts about the mathematical validity of renormalisation but that since it worked they didn't really care -- and it does work, admirably.
This formalism of electromagnetism is a quantum field theory, and was developed in the late 1940s. In the 60s and 70s there was a push to unify it with another quantum field theory, that of the weak nuclear force, a push that culminated in the Weinberg-Salam theory. At high energies, the two forces merge, and we're left with the electroweak force. The weak nuclear force is similar in its quantum description to the electromagnetic force, although at lower energy levels, since it's carried by massive particles it has a small range. There's also always been effort into unifying the electroweak force with the strong nuclear force. These are known as Grand Unified Theories and there are quite a few of them. I'm not aware of anyone who seriously doubts that the electroweak and strong forces merge at higher energies, but I also must admit this isn't my area of expertise and I can't do much to describe the resulting theories, other than that we still don't actually possess a fully convincing GUT. I do know that some of the issues are caused by the nature of the strong force, which is highly confined and, frankly, a total nightmare to work with. Unlike the force carriers in the electromagnetic and the weak theories, the force carriers in the strong theory (known as gluons) are tightly coupled, and the theory is non-perturbative. In QED we're helped enormously by the weakness of the electromagnetic coupling, which then allows us to take a horrific interaction and expand it, effectively, as a Taylor series. Pictorially, this is demonstrated by Feynman diagrams -- you have the bare interaction, then you add in single-loop corrections, then two-loop corrections, three-loop, and so on. (In reality, you don't do three-loop corrections if you can possibly avoid it. What a horrible idea. Two loops are more than bad enough.) Unfortunately in the case of the strong theory, we can't do this. Instead practically everything has to be modelled numerically, which is where the "lattice gauge theory", or in this particular context, "lattice QCD [quantum chromodynamics]", which you may have heard passing reference to comes in. All that means is that you literally introduce a lattice, describe the theory on it, and then make the lattice as fine as your hardware will allow.
Anyway. The point is that while we don't have a fully developed way to marry quantum chromodynamics with the electroweak theory, the two definitely combine. Interestingly, at higher energies it looks as though gravity should *also* combined, which is where ideas of a theory of everything, unifying all four forces, comes from. Personally I find this a bit more specious, not least because there are only two forces that extend beyond the nucleus, and of those only one of them is actually exhibited as a force -- gravity acts in every way as if it's as fictional as centrifugal forces. It's true that we can write down a classical theory of a massless, spin 2 force carrier, call it a "graviton", and immediately recover the first-order perturbation to general relativity, but the fact that no-one has ever managed to quantise the damned thing without recourse to string theory is a bit of an impediment. But I may well be wrong. Hell, string theory might be the be all and end all that people who read Brian Greene seem to think it is, though I'd be very, very surprised.
"So, has science turned into religion, and everyone is going, "Well... because!" ? This constant appears to not even be constant, just constant for our measurements, right now. Because we're not measuring anything _else_, because we're not investigating its relationship for other energyes, taking into account other laws of physics, we're taking it at that value. Did everyone forget about the highly energetic creation of the universe?"
No, not at all. I think you've got this the wrong way round. I mentioned above that we look to higher energies and find that the electromagnetic and the weak nuclear forces should merge, and then at higher energies that force should merge with the strong, and that at higher again it looks as though it may merge with gravity. That statement is built entirely and fully on the changes in these "constants". (They should never have been called constants in the first place; the nomenclature is a hangover from a hundred years ago when no-one had reason to suspect that the fine-structure constant is not, in fact, constant; and that even Newton's gravitational constant is probably not actually constant.) They change with energy, and when you write down the detailed theory, they change in a very well-defined way. The fine-structure constant dictates the coupling of electrons to photons in quantum electrodynamics -- and its value of around 1/137 is why a perturbative approach to QED works so well. At higher energies, this quantity and a similar "constant" governing the couplings in the weak theory reach the same (still non-constant) value. At a higher energy again, this combined coupling seems to reach the same value as its analogue in the strong nuclear theory. In gravity, the place of the "coupling" is taken up by a quantity which is effectively the Newton constant, and various speculative changes to the nature of general relativity suggest -- and this one is almost, though not quite, entirely speculative -- that the Newton constant at extremely high energies will also end up lying at the same value as this GUT coupling.
We take the fine structure constant to be 1/137 because that's basically what it is. If we're working in higher-energy environments, we allow it to "run" up to its value at that energy. I can assure you that it's accounted for.
(What is quite interesting is how constants tend to appear in combination with one-another, and particularly in conjunction with the speed of light and with Planck's constant. Allowing more things than just the couplings to vary gives one a hell of a lot of leeway to seriously fuck up your physics in all-new and exciting ways.)
(Score: 3, Informative) by boristhespider on Sunday February 08 2015, @07:22PM
This figure may help
http://www.nobelprize.org/nobel_prizes/physics/laureates/2004/phypub4highen.jpg [nobelprize.org]
(Score: 3, Interesting) by Anonymous Coward on Monday February 09 2015, @01:50AM
(Score: 3, Funny) by melikamp on Monday February 09 2015, @02:13AM
(Score: 2) by boristhespider on Monday February 09 2015, @10:15PM
If there's something that I didn't make clear - which wouldn't at all surprise me - then feel free to ask someone to elaborate (or rephrase, or condense) and if it's not me there are a couple of other posters on here who are familiar with relatively high-level physics. I'd be genuinely happy to try and rephrase. I've commented before that finding a level to pitch at is pretty tough.
I'm also open about the fact that I'm a cosmologist first and a gravitational theorist second; I'm not, and nor have I ever pretended to be, a particle physicist, merely someone who probably has a bit more familiarity with the field than many others on here.