Fundamental Constant Possibly Inconsistent

dylanduck writes "Cosmologists have begun thinking that yet another fundamental constant of nature is, er, not constant. The constant in question is the ratio of a proton's mass to that of an electron. It governs the strong nuclear force but there's no explanation for why that ratio should be constant. If true it would provide support for string theory, which predicts extra spatial dimensions." From the article: "Researchers at the Free University in Amsterdam in the Netherlands and the European Southern Observatory in Chile discovered the variation in mu. They did it by comparing the spectrum of molecular hydrogen gas in the laboratory to what it was in quasars 12 billion light years away. The spectrum depends on the relative masses of protons and electrons in the molecule."

Re:Electron Constants not Constant??!!

[FreezerJam]

...maybe http://en.wikipedia.org/wiki/The_Quiet_Earth [wikipedia.org] is more informative.

(not in the habit of checking Wikipedia for movie details ... hmm)

Intelligent Design?

[RSquaredW]

Hmm, wasn't one of the arguments for intelligent design that the fundamental constants had to be "just right" for the universe to exist? If the shifts of other dimensions causes shifts in our universal constants...another nail in the necessity-of-God argument's coffin?

String theory makes my head hurt.

Hmm...

[PiMuNu]

It's interesting that they think the ratio effects the strong force. Electrons don't see the strong force, so I'm not sure that this is true - anyone know any better?

The result is accurate to 3.5 sigma - so (possibly) good to about 95 %. Based on a new model of H2 molecule, not sure how well verified it is. I suspect any fool could make any non-standard model measurement fit with string theory so I wouldn't read too much into that.

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[account_deleted]

Comment removed based on user account deletion

Re:Hang on a second...

[PiMuNu]

Don't forget the proton is a composite of quarks. So the mass of the proton is a function of the mass of the quarks and the binding energy. A hack but E=mc^2, so m(proton) = m(quarks) - (binding energy)/c^2. The binding energy changes if the strengths of the forces that bind it change. This means that a change in the electromagnetic force (e.g. changing alpha fine structure constant) or the strong force will change the mass also. Of course, the mass of the electrons or quarks could have changed as well :P

Re:Does this mean

[maxwell demon]

that I face the risk that the first 100 digits of PI that I have memorized could change, and the knowledge becomes useless?

Well, that was true since Einstein: The value of pi as you learned it is only valid in Euklidean (flat) space, and our space is Riemannian (curved). However, to your relieve, the Riemannian space is locally Euclidean, so if you restrict yourself to a small enough volume, your 100 digits are accurate again. Unless you get into trouble with quantum physics (I'm now too lazy to calculate if you could get 100 digits of pi right on Earth without getting close to the Planck length).

Mind-blowing...

[fritzk3]

No, not that the constant might not be constant. What's mind-blowing is that an article posted by Zonk might actually be more than mere tripe... possibly even worth reading! Man, maybe the universe *IS* just that screwed-up!

Re:.002% change

[shma]

Mass is more fundamental than you imply in your statement. The mass of the electron is not found by simply 'weighing' it (measuring its gravitational force under earth's gravity), as you suggest. Of course, you know that force, any force, is related to acceleration through mass, and in the electrons case, we use mangetic force experiments to determine its mass. The force of a magnet on an electron (mass m_e) is F_B = m_e a_B = qvB, where v is the velocity of the electron perpendicular to a magnetic field of strength B.

It turns out that quantum mechanically, this results in the discrete energies of an electron in an atom to be dependent on the mass as well, through the mass to charge ration e/m. Experiments observing atomic spectra can, and have, measured this to great accuracy.

For a more fundamental defninition of what mass is, we can work it out in terms of fundamental constants, whose constancy, at least for now, has not been challenged: sqrt(h*c /G), (where h is planck's constant, c is the speed of light, and G is Newton's gravitational constant) has the units of mass, and is given the name of "the Planck mass". This can be used as a fundamental unit of mass, in the same way one lightsecond is used to define the meter (1 ls = 299 792 458 meters exactly).

Re:"If true"

[NichG]

Well, it'd be an example of a piece of experimental evidence in a field where basically you can't test anything because of the lack of experimental evidence. If that mass ratio varies, then this also means we can measure how it varies, and each theory can make a prediction and... I suspect they bring up string theory because thats the one everyone knows, not because this particular piece of evidence gives support to string theory only. But on the other hand, I can't really say off the top of my head which of the successor theories predicts that the masses of composite particles can have a time dependence (which would amount to either the strength of the strong force or electromagnetic force having a time dependence, or the quark and/or electron self-masses have a time dependence). If all of them do, and can't actually predict how it would vary, then yeah this isn't so useful.

But if its true its still pretty neat and its like water in the desert for the field of post-QM/GR theories.

Constant?...sounds like a Global Variable

[CaptainPinko]

To me it sounds like these values aren't actually constants but more like global variables. No matter where you are, at any one time the value is the same. So it is constant with respect to position, motion, etc. However, across time the value can change... but it will change universally so that it remains "constant" (in the sense that I mentioned before hand).

Of course this is unfortunate because this means any sufficiently sophisticated simulator will require global variables to run. Dijkstra will be aghast when in the future it is discovered that the universe requires "goto"s too!

Re:.002% change

[Enrique1218]

Ah yes, you use the force to describe the mass. I am familiar with those experiment. But, they relied on macroscopic force to describe mass which may be problematic when applied to a single electron and the spectra which come from the discrete energy level that arises from the Hamiltonian that assumes mass is invariant (which it probally is compared to the potential). So again, what is mass? You mention distance which in our own perception is the separation between two points. How do you phyically describe mass for an electron or even something smaller than that quarks. Granted, we hold it to be intrinsic like spin. It is a useful concept and vital part of our mathematical modeling in QM. But, why is it so important to our description of energy quanta. Does one particle know the mass of another? If so, how?

Re:This has nothing to do with Heisenberg...

[hubie]

Actually, the complementary variables are position and momentum, and energy and time. If you want to get really technical, you can throw in the quantum mechanical spins as well.