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Physicists War Over a Unified Theory
beggs writes: "I was looking through the New York Times and came across an article which talks about a new front in the war to find a unified theory, but this one does not come from the particle physicists, it comes from the solid state physicists. Here is a little quote for wet your appetite: 'some solid-state physicists are trying to show that the laws of relativity, long considered part of the very bedrock of the physical world, are not platonic truths that have existed since time began.'"
Absolutely. Einstein's theories superseded Newtonian physics, though Newton's system works just fine for most things here on Earth. It's only when one approaches the speed of light that you find the discrepancies pointed at by Relativity -- and discover how matter and energy interrelate.
Einstein's work may also not adequately describe the universe in some instances; it cannot satisfactorially explain how the universe came into being. A new theory that can do so can hopefully be found -- and if it is, it will very likely teach us new things, things that may affect our every day life, just like Einstein has.
This reminds me of pascal's image of knowledge...
:)
Where knowledge is symbolized by the sphere's volume and the unknown by the sphere's surface. Therefore as knowledge grows, so does the unkown (although the volume grows faster than the surface, total wisdom will be never achieved.)
(or if the sphere is a balloon, science grows until it explodes
This isn't quite correct. You are right that in changing the speed of light you are only redefining the time unit. (One second is how long a photon takes to travel a certain distance.) In everyday work, (yes- I am a physicist) I choose units where c is one. It makes things so much easier.
What the physicists are measuring isn't the speed of light - it is the dimensionless constant alpha. Since alpha is dimensionless, you cannot renormalise changes in it by changing the size of your units. (Alpha is a measure of the strength of the electromagnetic (and electroweak) force.)
Quantum mechanics is the thing we know least about. We have tested general relativity to fourteen decimal places, but QED (quantum electrodynamics) has only been tested to ten decimal places. Quantum is a theory filled with ad-hoc rules. GR is increadibly simple. It wouldn't surprise me at all if quantum field theory was shown to be a suitable limit of what happens to gravational waves once non-linear effects become important, and once you start running into the effects of compactified dimensions.
You are forgetting something. Before the great paradigm shifts in the history of physics (Newton, Einstein, Bohr, etc.), there was always evidence that something was wrong with prevailing theory. Scientists on the front lines weren't "comfortable", they noticed things like the "ultraviolet catastrophe" and the precise spectra of atoms and knew something was wrong.
Today we know that general relativity and quantum mechanics don't work together, but we aren't sure how to fix it (though string theorists try hard).
Eventually it's conceivable that we'll write down some basic laws and then millenia will pass without any evidence that something is still wrong. While you're right that it's impossible to prove that these laws are correct, scientists are very diligent about trying to find holes and if none are found, then everyone will believe we finally know the truth. And perhaps we actually will.
Mathematics is entirely artificial. It's based on rules and premises that we pretty much made up. You can prove things in math because it's a self-contained problem set, and you're looking at it from the outside with an omniscient view.
When you didn't invent the framework of the problem, it tends to be harder to prove a solution.
That said, you may never be able to prove a Unified Theory, because you can't ever be certain you've described every aspect of the problem set. But you can disprove a physical theory (or at least show it to be lacking) simply by finding a counterexample.
To expand on the previous explanation, as far as Plato is concerned there exists the universal idea of "chair". We may see isolated instances of "chairs", but the only reason we know these are chairs is because they are reflections or shadows of the universal (true, global, ) Chair.
I would suspect that most of us think the other way around: society has taught us to use the word chair, and now their is a general consensus of what a chair is. Thus the universal idea arises from the details. Plato would have argued that the details arise from the universal idea.
If you think this is a philosophical argument, then I think you missed the point.
The most important point isn't whether there are emergent organizing principles at different levels, because everyone knows there are. The real arguments is whether or not "fundemental" particles are really real. The particle physics community believes they've got a grasp on the basic building blocks of reality, but then some solid state boys come along and offer a theory saying they don't really exist at the base of things.
Think of it this way. In the particle physicist mind, you don't need vacuum fluctuations to describe particles. They both have an independent existance. The solid state people have suggested that all particles are merely a consequence of the vacuum fluctuations. You can't have particles without the background.
While the two conflicting viewpoints do arrise from different philosophies, it also seems clear that there is an underlying truth. Either there are particles in full truth, or there is just a vacuum that makes it look like there are fully qualified particles. Ultimately it's the truth that's important, and this seems like an important difference to me.
In the late 19th century, Albert A Michelson, according to many the "Greatest" physicist of his time (and winner of the first Nobel prize in Physics (1907), decided to measure the speed of light...in 1878, he did so accurately for the first time, he was using about $10.00 of lab equipment, btw...his passion for accuracy and precision led to his teaming up with Edward W. Morley, in 1878 to prove the existence of the cosmic "ether", through the....
e du/lectures/michelson.html.....there's also a great page on Michelson here;....http://hum.amu.edu.pl/~zbzw/ph/sci/aam.ht m
Michelson-Morley Experiment. Michelson's career had been golden, and he was widely regarded as the best physicist of the 19th century. So, everyone "knew" that he would successfully prove the existence of the cosmic "ether", which would be the finally block in the edifice of Classical Newtonian physics...
instead, the experiment went completeley wrong, conclusively proved the lack of the cosmic ether, and Newton was kicked to the gutter (as an explanation for sub-macroscopic events)...
here's a link to a pretty good, non-technical account of this from U of Va....http://galileoandeinstein.physics.virginia.
In the 1950's, in the particle chambers of UCLA, strange traces were seen on the photograpic plates of particle collisions....physics of the time couldn't account for this particle, so the postdocs and the grad students waggishly nicknamed the unknown particle the "what-on", and many ignored it for over 20 years...
as instumentation and our undestanding of sub-nuclear particles became better, some other grad students, looking for new frontiers (and new dissertation topics), started researching the "what-on"...it has become....
The Quark and is now the center of the posh new "String Theory", which is yet another attempt to explain overall particle to particle interaction,and from the standpoint of "Classical Quantum Dynamics", Superstring theory kicks QD to the curb....here we go again.....
here's a good page on String Theory
http://superstringtheory.com/
the point being...these things we are discussing are so far beyond our abilities to directly sense or measure them, it's like the old story of the scientists examining an elephant in a lightless, closed room...
one scientist grabs the tail and thinks its a thin, long snake, another scientist grabs a tusk and thinks its a rhino, another grabs the trunk and thinks its a python...
since we have no ability to directly "view" or "measure" these things, we are using inference and deduction to provide us with our theories, yet as every generation of instrumentation improves and gives us new "information" we take that info and rework it...
face it, we could come up with a "Unified Theory" that completely explains our current "knowledge" about physics, to the satisfaction of 99% of the scientists on the face of the earth and....
it could be kicked over by some new experiment, just the way that Michelson-Morely kicked over "Classical" Physics...
Ten quid, she's so easy to blind. And not a word is spoken...
What??
:)
OK, first simple correction, actually, changing the speed of light changes the *distance* unit, not the time unit. We define time as cycles of a cesium atom, so the correct definition is that one *meter* is the distance light travels in some fraction of a second, per SI definition.
QED is the most well tested consistent theory that physics has ever seen. GR is not NEARLY as well tested as QED is. Blandly stating that QED has only been checked to 10 decimal places is crazy - QED is consistent to 10 decimal places with about 12 (if memory serves) completely different experiments. That's far more impressive than any test GR has undergone.
Alpha is the most well-known physical constant in physics right now, and suggesting that it changes, while it is possible, would not be in the least bit consistent with astrophysical findings. QED is more than consistent over well over several decades of orders of magnitude. GR doesn't win there at all.
QED is very simple, with absolutely *no* ad-hoc rules. The ad-hoc rules only come into play when
a) a physicist asks a meaningless question (What is the sound of one electron clapping?)
b) other forces come into play. You're talking about QED - that is, quantum *electrodynamics* - electromagnetism only, other particles/forces not invited! (Yes, this includes the weak force - otherwise QED would be quantum electroweakdynamics).
b) is to be expected, as a general unified theory doesn't exist yet, and a) is a simple extension of physicists who live in a macroscopic world trying to assign macroscopic ideas to a microscopic system (i.e. the 'location' of an electron). Any of Hund's rules could be seen to be ad-hoc as well, but a bit more theory and it all makes sense.
Now, if you mean the *Standard Model* is filled with ad-hoc rules, you're right. Neutrinos are all left handed... kindof. That sort of thing. That's correct. But QED is quite a solid theory.
GR is also anything but incredibly simple. It's simple only in the limit where you can take the interaction between two objects to be significantly greater than the Planck length, but anything smaller than that, and GR isn't so simple anymore. Simple reasoning: GR is continuous, QED is quantized. We can pull QED out from the quantized limit back to good old electrodynamics easily, but GR isn't nearly as lucky.
And, yes, I am a physicist as well, but I don't work in units where c is one.
The reason this is forbidden is because of relativity of simultaneity. I don't know why this part of relativity is less well-remembered than the relativistic length-contraction and time-dilation, but it is really the key to almost all relativistic "paradoxes."
In any FTL travel, there are two events, A: leave the origin; B: arrive at the destination. FTL travel is believed to be impossible because observers in different inertial frames of reference would disagree about whether A or B happened first! Since it is paradoxical to arrive before you have left, the events cannot be causally connected.