Posted on 04/20/2006 8:18:47 AM PDT by PatrickHenry
Indications of a change in the proton-to-electron mass ratio have shown up in comparisons of the spectra of hydrogen gas as recorded in a lab with spectra of light coming from hydrogen clouds at the distance of quasars. This is another of those tests of so-called physical constants that might not be absolutely constant. For example, the steadiness of the fine structure constant (denoted by the letter alpha), defined as the square of the electron's charge divided by the speed of light times Planck's constant, has been in dispute (see PNU 410). Some tests say alpha is changing, others say it isn't.
This is an important issue since alpha sets the overall strength of the electromagnetic force, the force that holds atoms together. Similarly, the proton-to-electron mass ratio (denoted by the letter mu) figures in setting the scale of the strong nuclear force.
There is at present no explanation why the proton's mass should be 1,836 times that of the electron's. The new search for a varying mu was carried out by Wim Ubachs of the Vrije Universiteit Amsterdam. He and his colleagues approach their task by studying hydrogen gas in the lab, performing ultra-high-resolution spectroscopy in the difficult-to-access extreme-ultraviolet range. This data is compared to accurate observations of absorption spectra of distant hydrogen (which absorbs light from even more distant quasars) as recorded with the European Southern Observatory (ESO) in Chile.
The astronomical hydrogen is essentially hydrogen as it was 12 billion years ago, so one can seek hints of a changing value for mu. Why the comparison? Because the position of a particular spectral line depends on the value of mu; locate the spectral line accurately (that is, its wavelength) and you can infer a value for mu. In this way, the researchers report that they see evidence that mu has decreased by 0.002 percent over those 12 billion years. According to Ubachs (wimu@nat.vu.nl), the statistical confidence of his spectroscopic comparison is at the level of 3.5 standard deviations.
Reinhold et al., Physical Review Letters, 21 April 2006
Laser Centre Vrije Universiteit (lab Web site)
Contact Wim Ubachs, wimu@nat.vu.nl
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That is an odd piece of information.
It is simple -- scientists are making measurements that indicate electron-proton mass ratios may change over time.
The questions in response have to address the measurement of the "old" hydrogen. Is it artifactual?
Then, is there a theoretical framework that such mass variation with time is proposed or accounted for?
bookmark for later reading
I think it means we are all coming apart. Can't we all just stay together, electromagnetically speaking!
It always calls for close scrutiny when a constant might not be as constant. Is it for real, or is it memorex, so to say.
The important point is that "There is at present no explanation why the proton's mass should be 1,836 times that of the electron's."
The Physics community should be working on this problem. A lot of other answers will come out of answering this question.
gravitational fields would change as celestial bodies move about, seems reasonable that these forces affect magnetism
Similar to work I've heard of where the rate of radioactive decay has not been constant.
... mu has decreased by 0.002 percent over those 12 billion years.
We're not looking at a big change in 12 billion years here, above the error of measurement or no.
Computations (unfortunately, unpublished) that I did about 20 years ago showed that the ratio between proton and pion mass could be determined to about 2 figures from the SU(3) color relations.
the researchers report that they see evidence that mu has decreased by 0.002 percent over those 12 billion years
Those folks who are seeing this 0.002 percent decrease as a chance to overturn the old earth evidence provided by radiometric dating perhaps should do the math before they pop the champagne corks.
But the mechanisms involved would be interesting to know...
Interesting article. As a spectroscopist, I would be interested to see how well the two techniques (lab vs quasar) measurements correlate. For such a small variation, there needs to be very tight control and validation of the instruments in question. Even in a tightly controlled lab with research grade instruments, slight differences in the performance of different optical benches can be observed.
Also, how did the researchers separate the various effects resulting in the appearance of a hydrogen line at the observed wavelength from known phenomena (like universal expansion for one, and Doppler effects as another, or even changes in the local electronic environment where the photon was emitted) from the alleged change over time of these constants? Is the researcher capable of simulating the interstellar environment of the distant hydrogen sufficiently in a lab (pressure, temperature, etc.)
Also, since the speed of light and Plank's constant are invovled in these constants, and these constants change over time, then how would that influence the properties of photons? If these properties were different when the photons were emitted, and the properties of a photon also depend on these properties, is there a discernable change in the photons in question comapred to contemprarily emitted photons?
This is interesting stuff, but I really look forward to replication by other researchers and other apparatus.
non-linearity can pop lots of corks
If the value does change, then it isn't a constant. It may be there are no constants among the fundamental characteristics as we know them, but if the value can be linked to something else a new constant would arise. Unfortunate for the popular science fans, these new constants would not be easily related to the way we commonly think of things we see, which put yet another level of misunderstanding between scientists and non-scientists.
I oft lay at night, head on pillow, george snorey on softly in the background, wondering much the same thing.
Well, No, not really.
In a few words, tho, beats the heck out of me too.
If anyone has the answer, it'll get posted here eventually... if it already hasn't been. :)
Entropy....the universe is going from order to disorder.
It also could be an effect of the streatching of the universe.
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