Posted on 06/30/2004 1:35:28 PM PDT by NukeMan
Speed of light may have changed recently
19:00 30 June 04
The speed of light, one of the most sacrosanct of the universal physical constants, may have been lower as recently as two billion years ago - and not in some far corner of the universe, but right here on Earth.
The controversial finding is turning up the heat on an already simmering debate, especially since it is based on re-analysis of old data that has long been used to argue for exactly the opposite: the constancy of the speed of light and other constants.
A varying speed of light contradicts Einstein's theory of relativity, and would undermine much of traditional physics. But some physicists believe it would elegantly explain puzzling cosmological phenomena such as the nearly uniform temperature of the universe. It might also support string theories that predict extra spatial dimensions.
The fine structure constant
The threat to the idea of an invariable speed of light comes from measurements of another parameter called the fine structure constant, or alpha, which dictates the strength of the electromagnetic force. The speed of light is inversely proportional to alpha, and though alpha also depends on two other constants (see graphic), many physicists tend to interpret a change in alpha as a change in the speed of light. It is a valid simplification, says Victor Flambaum of the University of New South Wales in Sydney.
It was Flambaum, along with John Webb and colleagues, who first seriously challenged alpha's status as a constant in 1998. Then, after exhaustively analysing how the light from distant quasars was absorbed by intervening gas clouds, they claimed in 2001 that alpha had increased by a few parts in 105 in the past 12 billion years.
Natural nuclear reactor
But then German researchers studying photons emitted by caesium and hydrogen atoms reported earlier in June that they had seen no change in alpha to within a few parts in 1015 over the period from 1999 to 2003 (New Scientist, 26 June) though the result does not rule out that alpha was changing billions of years ago.
Throughout the debate, physicists who argued against any change in alpha have had one set of data to fall back on. It comes from the world's only known natural nuclear reactor, found at Oklo in Gabon, West Africa.
The Oklo reactor started up nearly two billion years ago when groundwater filtered through crevices in the rocks and mixed with uranium ore to trigger a fission reaction that was sustained for hundreds of thousands of years. Several studies that have analysed the relative concentrations of radioactive isotopes left behind at Oklo have concluded that nuclear reactions then were much the same as they are today, which implies alpha was the same too.
That is because alpha directly influences the ratio of these isotopes. In a nuclear chain reaction like the one that occurred at Oklo, the fission of each uranium-235 nucleus produces neutrons, and nearby nuclei can capture these neutrons.
For example, samarium-149 captures a neutron to become samarium-150, and since the rate of neutron capture depends on the value of alpha, the ratio of the two samarium isotopes in samples collected from Oklo can be used to calculate alpha.
A number of studies done since Oklo was discovered have found no change in alpha over time. "People started quoting the reactor [data] as firm evidence that the constants hadn't changed," says Steve Lamoreaux of Los Alamos National Lab (LANL) in Albuquerque, New Mexico.
Energy spectrum
Now, Lamoreaux, along with LANL colleague Justin Torgerson, has re-analysed the Oklo data using what he says are more realistic figures for the energy spectrum of the neutrons present in the reactor. The results have surprised him. Alpha, it seems, has decreased by more than 4.5 parts in 108 since Oklo was live (Physical Review D, vol 69, p121701).
That translates into a very small increase in the speed of light (assuming no change in the other constants that alpha depends on), but Lamoreaux's new analysis is so precise that he can rule out the possibility of zero change in the speed of light. "It's pretty exciting," he says.
So far the re-examination of the Oklo data has not drawn any fire. "The analysis is fine," says Thibault Damour of the Institute of Advanced Scientific Studies (IHES) in Bures-sur-Yvette in France, who co-authored a 1996 Oklo study that found no change in alpha. Peter Moller of LANL, who, along with Japanese researchers, published a paper in 2000 about the Oklo reactor that also found no change in alpha, says that Lamoreaux's assumptions are reasonable.
The analysis might be sound, and the assumptions reasonable, but some physicists are reluctant to accept the conclusions. "I can't see a particular mistake," says Flambaum. "However, the claim is so revolutionary there should be many independent confirmations."
While Flambaum's own team found that alpha was different 12 billion years ago, the new Oklo result claims that alpha was changing as late as two billion years ago. If other methods confirm the Oklo finding, it will leave physicists scrambling for new theories. "It's like opening a gateway," says Dmitry Budker, a colleague of Lamoreaux's at the University of California at Berkeley.
Horizon problem
Some physicists would happily accept a variable alpha. For example, if it had been lower in the past, meaning a higher speed of light, it would solve the "horizon problem".
Cosmologists have struggled to explain why far-flung regions of the universe are at roughly the same temperature. It implies that these regions were once close enough to exchange energy and even out the temperature, yet current models of the early universe prevent this from happening, unless they assume an ultra-fast expansion right after the big bang.
However, a higher speed of light early in the history of the universe would allow energy to pass between these areas in the form of light.
Variable "constants" would also open the door to theories that used to be off limits, such as those which break the laws of conservation of energy. And it would be a boost to versions of string theory in which extra dimensions change the constants of nature at some places in space-time.
But "there is no accepted varying-alpha theory", warns Flambaum. Instead, there are competing theories, from those that predict a linear rate of change in alpha, to those that predict rapid oscillations. John Barrow, who has pioneered varying-alpha theories at the University of Cambridge, says that the latest Oklo result does not favour any of the current theories. "You would expect alpha to stop [changing] five to six billion years ago," he says.
Reaction rate
Before Lamoreaux's Oklo study can count in favour of any varying alpha theory, there are some issues to be addressed. For one, the exact conditions at Oklo are not known. Nuclear reactions run at different rates depending on the temperature of the reactor, which Lamoreaux assumed was between 227 and 527°C.
Damour says the temperature could vary far more than this. "You need to reconstruct the temperature two billion years ago deep down in the ground," he says.
Damour also argues that the relative concentrations of samarium isotopes may not be as well determined as Lamoreaux has assumed, which would make it impossible to rule out an unchanging alpha. But Lamoreaux points out that both assumptions about the temperature of the Oklo reactor and the ratio of samarium isotopes were accepted in previous Oklo studies.
Another unknown is whether other physical constants might have varied along with, or instead of, alpha. Samarium-149's ability to capture a neutron also depends on another constant, alpha(s), which governs the strength of the strong nuclear attraction between the nucleus and the neutron.
And in March, Flambaum claimed that the ratio of different elements left over from just after the big bang suggests that alpha(s) must have been different then compared with its value today (Physical Review D, vol 69, p 063506).
While Lamoreaux has not addressed any possible change in alpha(s) in his Oklo study, he argues that it is important to focus on possible changes in alpha because the Oklo data has become such a benchmark in the debate over whether alpha can vary. "I've spent my career going back and checking things that are 'known' and it always leads to new ideas," he says.
Eugenie Samuel Reich
Being a Capricorn would make him less of a Cancer. At least may have stuck to the Tropic at hand.
Not exactly a big help for the Young Earth Creationists, is it?
Thanks for the explanation.(125) I didn't know that.
It stands to reason that light would be subject to the law of entropy also
Like , I said in my follow up "Oops, I misread and went another direction. That's an easy mistake to make since scientists around the world have been debating the other direction for over ten years. And frankly this would be the first bit of opposing, as in the opposite direction, theorizing that I have seen. I'll have to wait on peer review for this one. And like I said, the momentum is sliding towards cdk not "c speed up."
The electric universe hypothesis is the brainchild of Australian neo-Velikovskian physicist Wallace Thornhill, by which he seeks to eliminate gravitation altogether and explain all of nature by electromagnetism. The result is some pretty bizzare stuff, including the electric star hypothesis. This hypothesis holds that the source of solar (and stellar) heating is at the suface, and not in the interior. Surface heating is caused by a heavy bombardment of relativisitic electrons accelerated towards the sun by its extremely large excess positive electric charge. There are a lot of reasons to be suspicious of such an argument, which I discuss in this rather long transcribed mailing list message from 1998.
link to Thompson's e-mail exchange with Thornhill: http://www.tim-thompson.com/grey-areas.html
further comments by Thompson regarding Electric Sun theory: http://www.tim-thompson.com/electric-sun.html
In short, the electric sun/plasma Universe stuff is based on the presuppostion of the validity of ancient myths, and its true believers torture science to no end in their efforts to bend it to their will. Thornhill offers no model, only prose, in support of his beliefs.
Contrast this with some of the people on this website who have genuine science credentials; who is more believeable -- some guy from Australia with a BS in 1964, and who has bought into the Velikovskian mythology, or the scientists we have here on FR, who are more than happy to address reasonable questions and explain how science can explain all those things that Thornhill keeps telling you it can't?
At last...the admission we have all been waiting for. ;)
And it works well enough for us to "get from one planet to another".
You know what my vote is...as for the rest, it is much easier to pretend to understand Velikovski, than real science.
Some who follow E.U. are *Saturnists..the premise that the Earth was once in orbit around Saturn..then moved to its current address.
Some who follow Halton Arp join E.U...
many are just tired of vague answers to reasonable questions.
Carl Sagan ..*Super Greenhouse and other quotes just don't cut it anymore..allong with *Dark Matter etc.
Some who follow E.U. are like myself.
See Electrical flow in greater import of working..as a medium..as a catalyst.
My personal interest in posting E.U. links and article excerpts is to invite others to go seek for themselves....draw their own conclusions.
Wal is not the only forwarder I visit...theirs individuals at Goddard...EX and current JPL/NASA types who chat E.U. on the internet on forums.
I have collected PDF H1 assays from Aricebo..with Electrical continuity comment concerning background ...comment on Redshift that leans toward Halton Arp.
As mentioned in some posts..I ran a CNC Plasma gantry..underwater cut..steel and alloy on huge scale.
Nitrogen and Cryo nitrogen base.
did ultrasound testing....X,ray..and welding.
E.U. makes sense to me....yet I do not totally discard *Gravity.
Victor Clube of Armagh observatory and his partners forward *catastrophism as a catylist sequencer in our Solar system.
Nasa has regressed debrie trains and forwarded hypothesis that one or more moons has fragmented in times past.
Nasa even admits Mars had a different orbital configuration in times past.
Today..went googling to refresh on orbitor Galileo.
so ya..Galileo passed to close to IO and got Radiation..then encured chip damage in its computer.
Others comment that Galileo's onboard system wheir damaged by electrical current..which is flowing between Jupiter and Io....5 Million Amphere's I believe the recorded figure.
Each swing by ..by our orbitors only sustains the Electrical reality at work in planets and output of electricity.
You can google on Neptune and Uranus and get all kinds of varied data assay's and depth measures.
yet both have nearly liquid metal slurry's inside whirling at great speed with offset magnetic axis's.
Their is the resonance debate...how many worlds are *capture..which directs debate concerning the accretion disc theory.
E.U. is sure to be wrong at many points.
Its a new construct....I'm comfortable...I'm in for the long haul.
Velikovsky was mocked to derision by the academic.
yet his perception of Catastrophism driving change on worlds..and causing planetary movement is not so stupid after all.
Our Sun/Solar system porpoises up and down the galactic plain.
We are presently some 8 degree's above the dense mid Galactic plain.
For some great length of time our Sun was inside a Spiral Arm of Orion..we are presently just above the inner edge of the spiral arm....having passed thru a disintegrating Giant Molecular Cloud...the young Blue Stars of the Gould belt..part of the disintegrating GMC.
Passage thru boundry zones such as these forward the possibility of energy exchange..gravametric distortions.....bombardment episodes.
From the revision drafts I have read from Arecibo..to NASA/JPL forwards....we are still learning.
we live in a time of revision and awe.
I will enjoy it..and stand with Velikovsky,Clube,Napier..Arp and others......even sarcastic Thornhill : )
Did they put up new signs. I've been driving around at the old speed. This explains why everyone blows their horn and flips me off even though I'm in the right lane.
The speed of light and the color of light are related. If the speed of light has increased, would the old light from galaxies long ago and far away appear to be redshifted?
A darned good question that I hope someone with a good understanding of the physics of light will answer for us.
Bizarre that anyone still, er, waves this around. There is a limit to which light is a wave. The first such limit was noticed in the Michelson-Morely experiments, in which light absolutely refused to act like a wave propagating through a static medium. (One's motion through space should make a difference when measuring the speed of light in such a case and it does not.)
Einstein in 1905 observed that light sometimes still acts more like a beam of little thrown rocks than a wave. It became necessary to resurrect the particle theory with the concept of the photon. It was further observed in various diffraction-grate experiments with one-at-a-time photons that light will act as a wave (propagating on a broad front and forming interference fringes) in some cases and a stream of particles in others depending entirely upon whether one is keeping track of which path the photon takes.
One ignores a lot to still be telling people that light is ripples in some kind of ether.
Agreed. A billion years here and a billion years there and pretty soon you are talking about a lota time.
As best I can figure, the speeding of light in "recent" times (i.e, post-emission along the way) would BLUE-shift the light as we see it here and now compared to how it would have looked to someone near the emitting object back when.
Very nice.
But I should mention that the Michelson-Morely experiment had already proved that you can't just use particle theory, either. You don't get the Newtonian addition-of-velocities predicted by particle theory any more than you get the relative-to-the-medium velocity predicted by waves-in-ether theory. You don't get any difference at all no matter how you're moving or where you aim the light beam.
It was the opening for various theories leading in a few decades to Special Relativity.
Hi!
Did you follow the Cassini SOI last night?
None of the cable channels showed it so I ended up in my son's room watching NASA TV on the computer.
I take it you're "Holden" out for something to turn modern physics on its head...
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