Both of these studies were done on multiwalled tubes since they are larger and it's easier to make attachments with them.
In the earlier study in Science, the authors from SEM imaging noted that it was actually the outer single-walled nanotube that broke first therefore it was carrying the load. This would make sense from the way the attachments were formed which could only form a bond with the outer surface of the multiwalled tube. Therefore the numbers quoted were for the strength of this outer single-walled nanotube using as thickness only that of this single-walled nanotube.
However, in the later study in Materials Science and Engineering, the authors believed the attachments were made to all the layers of the multi-layered nanotube, which would explain their higher measured strength.
The prevailing theory is that the range of strengths is due to the number of imperfections in the nanotubes. So we should be able to look at the nanotubes at the nanoscale using SEM,'s, STM's or AFM's and find which ones have the least imperfections. These should be the strongest tubes.
In the Science study, 1 out of 21 of them, 5%, have the best strength, 63 GPa. At a production of millions of tubes at a time this should still be feasible economically and technically.
The lengths of the nanotubes in these studies were however, were at the micron scale though. Nanotubes have been created at the centimeter length scale, but as far as I know the strength of these have not been tested.
Note that the reported strengths of centimeter long or longer "fibers" made of nanotubes being less than 1 GPA are not measuring the strength of individual nanotubes at these lengths. This is because the fibers are composed of the nanotubes stuck together end to end by weaker Van der Waals forces, rather than the much stronger carbon-carbon bonds that prevail in individual nanotubes.
Here is one study that detects, characterizes defects in the nanotubes at the nanoscale:
Methods such as this might make it possible to find the nanotubes with the least defects beforehand and therefore automatically select those of the highest strengths.
"No - these calibration images are taken with the L4, L5, L6 filters. There are images of the color wheel in all the filters (L1-7, R1-7), but very limited ones of the surface/sky in anything but L2, L5 and L6. In fact, there are now L4 images available. The true colour sky looks white, but does seem to have a greenish tinge to it.
You can try this yourself if you have an imaging program that lets you use RGB colour channels. If you put color wheel images using L2 in red, L5 in green and L6 in blue, and move back to full colour, it looks nothing like the images you linked to. Blue looks bright pink-purple. If you use L4, L5, and L6, the colours come out just like that image you showed. Most of the posted colour images are colourised using the three main imaging filters (L2, L5, and L6), because those are the mainly used ones. It makes sense, the image quality is better, but one down side is that it doesn't give you as close a real colour as the L4 filter does."
Thanks for the response. Where do you locate the individual filter images with the labeled data about which wavelength they represent?
Also, I can understand that with scientific observations the near-infrared might be very useful, but it seems to me for an image to be released to the news media for public relations the red filter would be used to give the most accurate color rendition of the surface.
For the released color images you mention using the correct L4 filter are you referring ones visible here:
http://apnews.myway.com/image/20040110/MARS_ROVE R. sff_RS103_20040110150347.html
"This is all true, I remember hearing about it and seeing it demonstrated years ago. Anybody that's in amateur astronomy is familiar with this, too. After a while, all of your charts look the same in red light or daylight. But that's not the issue here. Although the evidence from elsewhere on his site is pretty good that this guy's a few bricks short, the problem here is not differences in human eye/brain color correction based on ambient light. The camera (or software, or whatever) is making the corrections in these images, not our eyes. If the calibration wheel looks different on the Mars image than it does on the lab image, you correct the color of the Mars image so that the it matches the lab image. That's the whole point of having a calibration device.
There is a reason for everything. Sometimes that reason just sucks."
The point is the images of the calibration target TAKEN ON MARS look perfectly fine, including the blue and the green:
http://marsrovers.jpl.nasa.gov/gallery/press/spi ri t/20040108a/PIA05018_br.jpg
It is only the images that also show the surface or sky that wind up giving the calibration target the wrong color.
See, there's a control.
"I've done a bit of experimenting with these files, comparing the colour wheel to the images taken on Earth, and in order to get a reasonable approximation of the 'true colours', you need the L4, L5, and L6 filters, for red, green and blue respectively. Ironically, the main problem is that there aren't yet pictures using the red filter. A lot of the images triplicated with the blue green and infrared images. (L6, 480; L5 530; L2 750)
The use of the L2 infrared filter means that the blue colours are oversampled (at least on the colour chart). Once the L4 filter images are used on the planet, full colour images will be ours. -- IANAL, BIPOOTV"
This still doesn't explain why the image of the sundial has the colors looking perfectly fine including the green and blue.
It's only the images that also show the surface or sky that wind up with the wrong colors for the calibration targets on the sundial.
Are you saying this image of the sundial was taken without using the red filter:
http://marsrovers.jpl.nasa.gov/gallery/press/spi ri t/20040108a/PIA05018_br.jpg
This argument doesn't work. NASA showed images of the calibration targets *on Mars* clearlys showing the blue and green calibration targets.
But the Martian surface and sky aren't visible in these images. It is only in the images showing the surface and sky do the blue and green calibration targets have the wrong color.
From: Robert Clark (rgclark@my-deja.com)
Subject: Microwave powered ion drive.
Newsgroups: sci.astro, sci.physics, sci.space.policy
Date: 2000/07/30
Found this site while looking up info on microwaves:
Physics inside a Microwave Oven
http://home.earthlink.net/~marutgers/fun/microwave/microwave.html
One of the demonstrations on this page appears to show plasmas being
generated by heating grapes with a microwave oven. Nice Quicktime
movies here. It's also described on the page:
HOW THINGS WORK: Microwave Ovens
http://rabi.phys.virginia.edu/HTW//microwave_ovens.html
Would this provide a low energy means of creating the plasma required
for ion engines? One means of creating the required plasma is by
irradiating the propellent gas with intense laser or x-ray beams to
strip off the electrons of the atoms of the gas, producing an ionized
plasma. However, these are both high-frequency forms of EM radiation
and therefore require high energy to produce. Microwaves being longer
wavelengths require less energy to produce.
Another means that is actually used for the Deep Space 1 probe is to
use electrons emitted by a cathode to irradiate the gas, ionizing it.
How does the energy requirement for the heating element of a cathode
compare to the energy requirement for producing the microwaves?
If this can be exploited as a low energy means of producing plasmas
then this might be used not only for low thrust engines as on DS 1 but
also for lauching ships into space by beaming the microwaves into a
reaction chamber of a rocket lined with, er, grapes.
--
________________________________________________
"In order for a scientific revolution to occur,
most scientists have to be wrong"
-- Bob Clark
________________________________________________
Another recent story discusses the applications of using cold plasmas:
Force Fields and 'Plasma' Shields Get Closer to Reality,
http://www.space.com/businesstechnology/technology/cold_plasma_000724.html
An advantage of the cold plasmas is the low power required to generate
them. However the article mentions that hot plasmas can be generated
with higher densities. Perhaps the microwave plasma generation method
can match the efficiency of the cold generation system while allowing
the high densities of the hot plasmas.
From: Robert Clark (rgregoryclark@yahoo.com)
Subject: Plasma propulsion for access to space?
Newsgroups: sci.astro, sci.physics, sci.space.policy, rec.arts.sf.science
Date: 2002-11-05 21:21:09 PST
http://groups.google.com/groups?th=87680963df54e46 c
Bob Clark
And if microorganisms can exist in comets, all bets are off:
From: Robert Clark (rgclark@my-deja.com)
Subject: Bioluminescent bacteria in comets?
Newsgroups: sci.astro, sci.space.policy, sci.astro.seti
Date: 2001-03-05 12:48:18 PST
The post copied below dicussed the theory of Hoyle and Wickramasinghe that
influenza comes from comets. This might find support in the curious glowing
trails found during the Leonid meteor showers:
Lasers Brings Leonids Alive
http://www.spacedaily.com/news/leonid-99c.html
"According to Dr. Jack Drummond, the laboratory's Directed Energy
Directorate astronomer, the Leonid meteors leave behind trails which, unlike
ordinary meteors that fade in a matter of seconds, can last up to an hour
and are still unexplained.
"I call these lingering meteor trails 'glowworms in the sky' since they are
not only visible for minutes by chemical reactions, but are twisted by the
winds into serpentine shapes, appearing like snakes or worms,' Drummond
explained."
The trails have been found to be peculiar to the 33 year periodic Leonid
storm periods:
"The scientists hope to answer why the 'glowworms' are peculiar to the
Leonid storm periods, which occur every 33 years, and why they are rarely
seen at other times. They wonder if it may imply something about the
composition of the parent comet."
As the page describes them:
"The glow, called chemiluminescence, is the production of light from
chemical reactions similar to bioluminescence, the same kind of glowing
reaction found in biological entities such as fireflies and their larvae,
glowworms."
However, if it is true that comets can contain microorganisms then perhaps
these glowing trails are in fact due to bioluminescence in bacteria. Then
the reason they appear during the 33 year storm periods could be because the
Earth is closest to the parent comet during these times and the bacteria
more easily survive the transfer to Earth.
Bioluminescent bacteria are known to produce their light when they are
disturbed:
Blazing a trail
http://www.newscientist.com/ns/19991120/blazinga tr.html
Then the light in the Leonid trails could be triggered by the turbulence in
the air as the meteoroids streak through the atmosphere.
Most bioluminescence is of the blue-green color. This would be one thing to
check for. Another would be the spectroscopic signature of the molecules
that produce bioluminescence.
From: Robert Clark (rgclark@my-deja.com)
Subject: Sunspot correlation to influenza confirmed.
Newsgroups: sci.astro, sci.space.policy, sci.astro.seti
Date: 2001-03-05 11:04:20 PST
Found this on Slashdot.com:
Flu epidemics coincide with solar eruptions, B.C. study says
You're coughing, you're sneezing, you think you've just got the flu, but you
could be a victim of sunspots
http://www.nationalpost.com/home/story.html?f=/s to ries/20010302/489917.html
Some possible causes are a connection between flu epidemics and weather
which is known to be effected by sunspots or possibly the increase in
radiation during high sunspot periods damages the human immune system.
However, Hoyle and Wickramasinghe had noted this correlation earlier and
used this to support their idea that influenza comes from comets:
The Dilemma Of Influenza
http://www.spacedaily.com/news/life-00d.html
"Peaks of solar activity will undoubtedly assist in the descent of charged
molecular aggregates (including viruses) from the stratosphere to ground
level. Thus according to our present point of view serious influenza
epidemics would follow such peaks, provided the culprit molecular aggregates
were recently dispersed in the stratosphere from cometary meteor streams.
With a more or less regular occurrence of such meteor showers the limiting
condition may then be seen as the intensity of solar activity, leading
naturally to coincidences between the timings of pandemics or major
epidemics and sunspot peaks."
Germs from Outer Space! Researchers Say Flu Bugs Rain Down from Beyond
http://www.space.com/scienceastronomy/planeteart h/ flu_in_space_000121.html
In this page, the H & W theory was criticized for suggesting the higher
solar radiation could lead to more influx of cometary material:
"There is scant evidence of any science going on here," said Stanford
University physicist Christopher Barrington-Leigh, who studies the upper
atmosphere and lower ionosphere. "According to the authors, solar activity
'will undoubtedly assist in the descent of charged molecular aggregates,'
but this is unphysical and unfounded."
However, there is evidence that increased solar radiation can increase the
numbers of visible meteroids in the Leonid meteor showers:
Meteor Storm Science: A 301 Explantion
by Robert McNaught
Canberra - November 16, 1999
http://www.spacedaily.com/news/leonid-99h.html
"We know the solar wind has some influence on the particles producing visual
meteors. The radiation counteracts the Sun's gravitational attraction, so
particles orbit the Sun more slowly. This is why storms occur in years
shortly after passage of the parent comet. The exact time lag for the main
bulk of the particles depends on the range of masses and ejection
velocities, and the number of orbital revolutions before encounter."
McNaught along with Asher produced the most widely accepted theory for
predicting the occurrence of the Leonids. Asher credits a theory of Lyytinen
and van Flandern for including the effects of radiation pressure in
predicting the timing and intensity of the Leonids:
The Moonlit Leonids 2000
http://www.spacescience.com/headlines/y2000/ast1 0o ct_1.htm
"They've done some interesting work on the effect of radiation forces in
dispersing meteoroids," says Asher of Lyytinen and van Flandern, "and their
predictions could well turn out to be correct. If pushed, I would go with
our lower estimates of 100 per hour."
It is interesting to note that the Leonid display for 2000 did turn out to
be within the higher range predicted by Lyytinen and van Flandern using the
effects of radiation pressure:
The Moonlit Leonids 2000
http://www.spacescience.com/headlines/y2000/ast1 0o ct_1.htm
"This year's likely encounters with dust streams are tabulated below. The
higher estimates for Leonid meteor rates, in the range 200 to 700 per hour,
come from astronomers Esko Lyytinen and Tom van Flandern, who are analyzing
the streams in much the same fashion as Asher and McNaught have done."
Leonids 2000 Special Report
http://www.space.com/scienceastronomy/leonids_20 00 _sr_final.html
18 November 2000 results
"Activity began to increase November 17 at 10:00 p.m. UT, according to the
International Meteor Organization (IMO). Starting around 1:30 a.m. UT on the
18th, a rate of 200 meteors per hour was observed. This rose to a peak of
about 300 per hour around 3:45 a.m. UT.
"Individual reports indicate during a second peak, for which the Eastern
United States was the prime viewing location, the hourly rate jumped to 120
to 180, and higher in brief stretches.
"Short bursts produced reports of an hourly rate as high 450."
However, it should be noted that the Lyytinen and van Flandern prediction
used van Flandern's controversial theory that comets are in fact debris
clouds orbiting asteroids:
Skywitness: The Leonid Meteor Storm From Girne, Cyprus
http://www.discovery.com/guides/space/leonids/sk yw itness.html
Their work has appeared in a peer-reviewed journal:
Predicting the Strength of Leonid Outbursts
Earth, Moon, and Planets, v. 82/83, p. 149-166 (1998)
http://adsabs.harvard.edu/cgi-bin/bib_query?1998 EM %26P...82..149L
I don't know whether the same result could be obtained by including the
effects of radiation pressure with the standard model of comet composition
(in the interview on the "Skywitness: The Leonid Meteor Storm From Girne,
Cyprus" page, van Flandern claims that it can not.)
The predictions for the November 2001 Leonids by Asher & McNaught and by
Lyytinen & van Flandern are markedly different, which should provide a good
test of the accuracy of their respective models:
Predictions of upcoming Leonid activity, peak rates, and time of the peak.
http://web99.arc.nasa.gov/~leonid/1998.html
There is a difference between the effects of radiation pressure Hoyle and
Wickramasinghe are claiming from that of the Lyytinen & van Flandern model,
in that H & W seem to be saying higher radiation pressure would increase the
influx of cometary material already surrounding the Earth, whereas Lyytinen
& van Flandern seem to be only discussing the perturbations of cometary
material as the comet orbits the Sun, which would effect where and when the
Earth would meet the densest cometary streams. Note for example that by
including the effects of radiation pressure Lyytinen & van Flandern predict
a lower Leonid intensity for 2001 than does the Asher & McNaught model, as
shown in the tables in the "Predictions of upcoming Leonid activity, peak
rates, and time of the peak" page. However, note that the correlation
between flu outbreaks and solar activity is not exact. It may be that
determining the effect of solar radiation on cometary streams could provide
a more accurate correlation.
Another criticism of the H & W influenza theory is that the amounts of
infalling cometary material would be too small to cause the effects H & W
claim:
Germs from Outer Space! Researchers Say Flu Bugs Rain Down from Beyond
http://www.space.com/scienceastronomy/planeteart h/ flu_in_space_000121.html
"Matthew Genge, of the Department of Mineralogy at the London Natural
History Museum, has estimated the amount of comet dust that survives entry
into the lower atmosphere, and thus how frequently an average-sized human
might be struck.
"Genge figures that if you live to be 5,000 years old, you'll likely
encounter one comet dust particle. Were it to harbor a virus, you would
presumably have to inhale the particle, further reducing the odds of
infection."
However, recent research shows more cometary material than previously
thought can survive the plunge through the atmosphere:
Leonid Meteor Shower: Sowing the Seeds of Life?
http://www.space.com/searchforlife/leonids_biolo gy _001115.html
"Other researchers have shown that meteors both small and large do not heat
up as much as previously thought, allowing the possibility that dormant life
could arrive on an incoming space rock or, just possibly, embedded in the
dust grain of a comet."
"Atom holography is another stunning idea. Instead of making an image in light as done in conventional holography, atom optics would make the hologram of atoms. "
"Atom holography would create actual replicas, rather than images of light."
"What this means is, we could make a real, 3-dimensional replica of some object. We could copy objects." Meystre said.
"All of the individual steps to do this with nonlinear atom optics have been demonstrated. It's just a matter of making it work all together. I think it will happen in the next two or three years."
"Gah. I'm not the type to flame somebody for their grammar, but good god... What kind of sentence is this? What you thinking were?"
My sigfile goes, "The more harshly you criticize someone else, the more likely you are to be wrong yourself."
If is legitimate to say "What do you think the odds are?" then since the prepositional phrase "of Google acquiring such data" modifies the word "odds", the sentence as written is also legitimate.
TABLETOP LASER ACCELERATORS ARE BRIGHTER AND FASTER
Physics News 510, November 1, 2000
http://newton.ex.ac.uk/aip/physnews.510.html
Table-Top Fusion
Significant Physics on a Small Scale
Creating fusion used to be best left to suns and high-priced devices. Now scientists have managed it with a mere million-dollar machine.
http://www.abcnews.go.com/sections/science/Daily Ne ws/tablefusion990324.html
Yankee Ingenuity: Dartmouth Physicists Convert A Microcope Into A Free-Electron Laser
http://www.sciencedaily.com/releases/1998/11/981 11 2075829.htm
Such "tabletop" accelerators are currently in the million dollar range. But given the interest of physicists to make use of such devices, the cost will probably in the 10 to 100 thousand dollar range within 10-20 years.
Forum: sci.physics
Subject: New muon anomaly - implication for relativity.
Date: 02/09/2001
Author: Robert Clark
The recent measurement of the magnetic moment of the muon has been interpreted as a possible suggestion of supersymmetry:
'Milestone' Study Challenges Basic Laws of Physics, Universe,
http://www.space.com/scienceastronomy/generalscien ce/standard_model_0102 08.html
The paper on the research is available on the experiments home page:
The Muon g-2 Experiment Home Page,
http://phyppro1.phy.bnl.gov/g2muon/index.shtml
However, as discussed in the article on Space.com the measurements are dependent on special relativity. There were measurements of the decay of muons as a test of special relativity in the 70's. They supported special relativity within the precision of the measurements, that is, the errors were within the accuracy of the experiments. This new research can be interpreted as providing a more precise test of special relativity.
In my opinion, the approximate nature of special relativity, that is, Lorentz invariance, for real physical bodies is inherent in the mathematics of modern physics, both in quantum field theory and in general relativity. It is interesting to note that quantum electrodynamics which attempts to meld quantum mechanics with special relativity is very accurate when applied to the hydrogen atom but less so when applied to heavier atoms. These new measurements also show that QED while accurate for the light electron is less accurate when applied to the heavier muon.
The approximate nature of Lorentz invariance is discussed in a preprint by Jacobson and Mattingly:
"There is also reason to doubt exact Lorentz invariance: it leads to divergences in quantum field theory associated with states of arbitrarily high energy and momentum. This problem can be cured with a short distance cutoff which, however, breaks Lorentz invariance.
"For these reasons we entertain the possibility that there is a preferred rest frame at each space-time point. In particular, we seek a viable effective field theory incorporating a breaking of local Lorentz invariance."
Spontaneously broken Lorentz symmetry and gravity, p. 1,
http://xxx.lanl.gov/abs/gr-qc/0007031
Note also that if it is confirmed that Lorentz invariance is only an approximation, then that strongly implies that light speed can be exceeded at sufficiently high energies:
Forum: sci.astro
Subject: Superluminal speeds as an explanation of cosmic ray anomalies.
Date: 11/17/2000
Author: Robert Clark
http://x74.deja.com/getdoc.xp?AN=694810422
--
______________________________________
"The more harshly you criticize someone else,
the more likely you are to be wrong yourself.
The cause is a mystery..."
-- Bob Clark
______________________________________
I forgot to hit the "post as text" box, which is why the post is badly formatted. I considered reposting but readers of this site are so averse to repeating the same info.
Thanks for the info and the ref. to the paper. I'll check that out. I would also be interested in finding out how your group can interpret these new results as a test of Lorentz invariance.
I also just saw a news release on some research that suggests the speed of light might vary and be frequency dependent over cosmological distances. It was meant to address the conumdrum of the anomalous gamma ray detection from Markarian 501 that was discussed in one of the articles I cited. One of the co-researchers is the highly-regarded general relativity theorist John Ellis:
Einstein in need of update?
http://www.eurekalert.org/releases/tam-ein020901 .h tml
Space-Time Foam Effects on Particle Interactions and the GZK Cutoff
http://xxx.lanl.gov/abs/hep-th/0012216
The argument I'm presenting was taken from some debates I had on the sci.physics.relativity group a couple of years ago. Unfortunately, dejanews.com doesn't archive posts very far back anymore so those are no longer available.
A key point is philosophical/heuristic:
Is it reasonable that an equation of physics should be considered to be *exactly* true for the entire future of physics? Since we are not at the stage of having a final theory I don't think that is likely. However, note that the key idea that reaching and exceeding the speed of light would require infinite energy is based on the idea that the Lorentz transformation is *exactly* true, for if not you don't get the infinity by having a zero in the denominator.
One might argue that in the future Lorentz invariance will be replaced by a more accurate expression, but if it will not be *exactly* true at that time, surely it is not *exactly* true now.
I repeated this argument recently also in sci.physics.relativity and received the response that the conservation of energy is a counterexample to the idea that a physical equation should not be considered to be exactly true. However, remarkably, even conservation of energy is dependent on Einstein's transformation equations, so that deviations from these will also have an effect on how we interpret the conservation of energy. This is discussed in one of the papers that discuss violations of Lorentz invariance. I'll give you a reference if you like. The possibility that conservation of energy might also be violated is probably even a more jarring idea than that of violations of Lorentz invariance.
The mathematical reasons for doubting exact Lorentz invariance *for real physical bodies* are these:
The equations of both quantum field theory and general relativity have been found to be analogous to those of fluid mechanics. In fluid mechanics we also have the fact that for the approximate linear PDEs describing the fluid, exceeding the wave speed of the underlying medium would result in an infinite pressure. Naively, one might conclude no body can exceed the speed of sound in a medium. But of course mathematicians and engineers know these equations are approximations. These linear PDEs need to be replaced by the more accurate nonlinear PDE's that describe the fluid in transonic and supersonic situations.
One might take this to be just a coincidence that the most advanced equations of modern physics, quantum field theory and general relativity, both describe the vacuum with equations that are analogous to those of a material medium. But the predictions of those theories are also what one would expect for a medium. In quantum electrodynamics and quantum field theory in general we have the fact that you must make mass and charge renormalizations to describe the reactions of subatomic particles very close to the intense field of the nucleus.
The key fact about this in regard to this discussion is this: if Lorentz invariance is to be true, then *every* aspect of its predictions must hold, not just simply time transformations as measured by decay rates. If the *intrinisic* mass and charge have to changed when moving at high speeds close to the nucleus, then that signals Lorentz invariance is not holding in that situation. (Note this is not the "relativistic mass" change, and of course for Lorentz invariance to hold, charge must be invariant.)
One might say this is only true for subatomic particles close to the nucleus, but the equations of QED show in fact *this is true for a field of any intensity*, the corrections are just extremely small. This is discussed in papers describing how the speed of light is altered in regions of strong electrical and magnetic fields, which in itself is telling you that the vacuum has properties dependent on the energy content in a region that effect the *intrinisic* properties of bodies in that region.
When I had this discussion on sci.physics.relativity there was a fundamentally important fact about this being overlooked: not only do mass and charge renormalizations have to be made close to the nucleus, but THE DEVIATIONS IN MASS AND CHARGE GET WORSE AS THE SPEED OF THE PARTICLE INCREASES. I can not overemphasize the importance of this fact to the argument. As I said before the mass and charge renomalizations are signals of the failure of Lorentz invariance in these situations. That the deviations get worse with speed means the deviation from Lorentz invariance gets worse with speed. This is exactly what you would expect if it were true that this is analogous to the situation of a body traveling through a material medium and that given sufficient energy you can exceed the wave speed of the medium.
As I said the mathematics of general relativity also suggests Lorentz invariance should only be an approximation *for real physical bodies*. In general relativity is it said Lorentz invariance holds only "locally". This is defined to mean it only holds *at a point*, or equivalently it holds on a tangent plane. But in differential geometry on which GR is based, a property is said to hold locally, when it holds *exactly* on a small region of the manifold. According to differential geometry which is the mathematical theory deriving GR, Lorentz invariance does not hold locally using the definition used in that theory and in every field of mathematics that uses the concept of a manifold. In the primary reference work on GR _Gravitation_ by Wheeler, Misner and Thorne it says explicitly that in real space with curvature, containing real bodies inducing their own space-time curvature Minkowski space can not be expected to exactly hold. To me this is saying that Lorentz invariance does not hold exactly for real physical bodies in real space with curvature.
In the debates on sci.physics.relativity I only gave a heuristic reason that I think can probably be made rigorous that the fundamentally important fact that the deviations from Lorentz invariance get worse as the speed of the body increases also holds in general relativity: the fact that the effective "force" a body feels becomes greater as the speed of the body increases (this is discussed in the FAQ for the sci.physics.relativity group.) This suggests that the *intrinsic* mass of the body is increasing with speed. (Again this is not the "relativistic mass" correction.) However, I found an article in the American Journal of Physics that says this explicitly:
American Journal of Physics -- July 1985 -- Volume 53, Issue 7, pp. 661-663
Measuring the active gravitational mass of a moving object
D. W. Olson and R. C. Guarino
Department of Physics, Southwest Texas State University, San Marcos, Texas 78666
If a heavy object with rest mass M moves past you with a velocity comparable to the speed of light, you will be attracted gravitationally towards its path as though it had an increased mass. If the relativistic increase in active gravitational mass is measured by the transverse (and longitudinal) velocities which such a moving mass induces in test particles initially at rest near its path, then we find, with this definition, that Mrel=gamma(1+beta^2)M. Therefore, in the ultrarelativistic limit, the active gravitational mass of a moving body, measured in this way, is not gammaM but is approximately 2gammaM.
Note this "effective" mass of the body in a gravitational field is again not the simple "relativistic mass". To me this is again signaling that Lorentz invariance is only an approximation for real physical bodies.
Another article in AJP that appears to be saying this is by Steve Carlip:
American Journal of Physics -- May 1998 -- Volume 66, Issue 5, pp. 409-413
Kinetic energy and the equivalence principle
S. Carlip
Department of Physics, University of California, Davis, California 95616
According to the general theory of relativity, kinetic energy contributes to gravitational mass. Surprisingly, the observational evidence for this prediction does not seem to be discussed in the literature. I reanalyze existing experimental data to test the equivalence principle for the kinetic energy of atomic electrons, and show that fairly strong limits on possible violations can
be obtained. I discuss the relationship of this result to the occasional claim that "light falls with twice the acceleration of ordinary matter."
However, I'm only judging here by the abstract as I haven't had the chance to read this article yet. I also hasten to add that Dr. Carlip is a frequent contributor to the sci.physics.relativity group in which he argues against speeds surpassing the speed of light, so he would probably be opposed to the idea that Lorentz invariance is only an approximation.
These articles can be found by searching on AJP's site: http://ojps.aip.org/ajp/
Note I am suggesting that high speeds and energy content in a region can effect what are regarded as intrinsic properties. This of course implies these properties really are not intrinsic but are dependent on surrounding conditions. My view is that properties such as mass and charge will be found to be tensors dependent on the mass/energy distribution in their vicinity and indeed on that of the universe.
Slashdot Mirror
This article from doing actual measurements found a highest strength of 63 GPa:
P DFs/science-9.pdf
n s/16.MSE%20A334demczyk.pdf
1 /5502/283
Strength and Breaking Mechanism of Multiwalled Carbon Nanotubes Under Tensile Load.
SCIENCE, VOL 287, p. 637-640, 28 JANUARY 2000
http://bucky-central.mech.northwestern.edu/Ruoffs
This report showed actual measured tensile strengths up to 150 GPa:
Direct mechanical measurement of the tensile strength and elastic modulus of multiwalled carbon nanotubes.
B.G. Demczyk et al.
Materials Science and Engineering A334 (2002), 174, 173-178.
http://www.glue.umd.edu/~cumings/PDF%20Publicatio
Both of these studies were done on multiwalled tubes since they are larger and it's easier to make attachments with them.
In the earlier study in Science, the authors from SEM imaging noted that it was actually the outer single-walled nanotube that broke first therefore it was carrying the load. This would make sense from the way the attachments were formed which could only form a bond with the outer surface of the multiwalled tube. Therefore the numbers quoted were for the strength of this outer single-walled nanotube using as thickness only that of this single-walled nanotube.
However, in the later study in Materials Science and Engineering, the authors believed the attachments were made to all the layers of the multi-layered nanotube, which would explain their higher measured strength.
The prevailing theory is that the range of strengths is due to the number of imperfections in the nanotubes. So we should be able to look at the nanotubes at the nanoscale using SEM,'s, STM's or AFM's and find which ones have the least imperfections. These should be the strongest tubes.
In the Science study, 1 out of 21 of them, 5%, have the best strength, 63 GPa. At a production of millions of tubes at a time this should still be feasible economically and technically.
The lengths of the nanotubes in these studies were however, were at the micron scale though. Nanotubes have been created at the centimeter length scale, but as far as I know the strength of these have not been tested.
Note that the reported strengths of centimeter long or longer "fibers" made of nanotubes being less than 1 GPA are not measuring the strength of individual nanotubes at these lengths. This is because the fibers are composed of the nanotubes stuck together end to end by weaker Van der Waals forces, rather than the much stronger carbon-carbon bonds that prevail in individual nanotubes.
Here is one study that detects, characterizes defects in the nanotubes at the nanoscale:
Resonant Electron Scattering by Defects in Single-Walled Carbon Nanotubes.
Science 12 January 2001, Vol. 291. no. 5502, pp. 283 - 285.
http://www.sciencemag.org/cgi/content/abstract/29
Methods such as this might make it possible to find the nanotubes with the least defects beforehand and therefore automatically select those of the highest strengths.
Bob Clark
"No - these calibration images are taken with the L4, L5, L6 filters. There are images of the color wheel in all the filters (L1-7, R1-7), but very limited ones of the surface/sky in anything but L2, L5 and L6. In fact, there are now L4 images available. The true colour sky looks white, but does seem to have a greenish tinge to it.
E R. sff_RS103_20040110150347.html
You can try this yourself if you have an imaging program that lets you use RGB colour channels. If you put color wheel images using L2 in red, L5 in green and L6 in blue, and move back to full colour, it looks nothing like the images you linked to. Blue looks bright pink-purple. If you use L4, L5, and L6, the colours come out just like that image you showed. Most of the posted colour images are colourised using the three main imaging filters (L2, L5, and L6), because those are the mainly used ones. It makes sense, the image quality is better, but one down side is that it doesn't give you as close a real colour as the L4 filter does."
Thanks for the response. Where do you locate the individual filter images with the labeled data about which wavelength they represent?
Also, I can understand that with scientific observations the near-infrared might be very useful, but it seems to me for an image to be released to the news media for public relations the red filter would be used to give the most accurate color rendition of the surface.
For the released color images you mention using the correct L4 filter are you referring ones visible here:
http://apnews.myway.com/image/20040110/MARS_ROV
Bob Clark
"This is all true, I remember hearing about it and seeing it demonstrated years ago. Anybody that's in amateur astronomy is familiar with this, too. After a while, all of your charts look the same in red light or daylight. But that's not the issue here.
i ri t/20040108a/PIA05018_br.jpg
Although the evidence from elsewhere on his site is pretty good that this guy's a few bricks short, the problem here is not differences in human eye/brain color correction based on ambient light. The camera (or software, or whatever) is making the corrections in these images, not our eyes. If the calibration wheel looks different on the Mars image than it does on the lab image, you correct the color of the Mars image so that the it matches the lab image. That's the whole point of having a calibration device.
There is a reason for everything. Sometimes that reason just sucks."
The point is the images of the calibration target TAKEN ON MARS look perfectly fine, including the blue and the green:
http://marsrovers.jpl.nasa.gov/gallery/press/sp
It is only the images that also show the surface or sky that wind up giving the calibration target the wrong color.
See, there's a control.
Bob Clark
"I've done a bit of experimenting with these files, comparing the colour wheel to the images taken on Earth, and in order to get a reasonable approximation of the 'true colours', you need the L4, L5, and L6 filters, for red, green and blue respectively. Ironically, the main problem is that there aren't yet pictures using the red filter. A lot of the images triplicated with the blue green and infrared images. (L6, 480; L5 530; L2 750)
i ri t/20040108a/PIA05018_br.jpg
The use of the L2 infrared filter means that the blue colours are oversampled (at least on the colour chart). Once the L4 filter images are used on the planet, full colour images will be ours.
-- IANAL, BIPOOTV"
This still doesn't explain why the image of the sundial has the colors looking perfectly fine including the green and blue.
It's only the images that also show the surface or sky that wind up with the wrong colors for the calibration targets on the sundial.
Are you saying this image of the sundial was taken without using the red filter:
http://marsrovers.jpl.nasa.gov/gallery/press/sp
Bob Clark
This argument doesn't work. NASA showed images of the calibration targets *on Mars* clearlys showing the blue and green calibration targets.
But the Martian surface and sky aren't visible in these images. It is only in the images showing the surface and sky do the blue and green calibration targets have the wrong color.
Bob Clark
Could you post images with the color corrected?
Bob Clark
From: Robert Clark (rgclark@my-deja.com) Subject: Microwave powered ion drive. Newsgroups: sci.astro, sci.physics, sci.space.policy Date: 2000/07/30 Found this site while looking up info on microwaves: Physics inside a Microwave Oven http://home.earthlink.net/~marutgers/fun/microwave /microwave.html
One of the demonstrations on this page appears to show plasmas being
generated by heating grapes with a microwave oven. Nice Quicktime
movies here. It's also described on the page:
HOW THINGS WORK: Microwave Ovens
http://rabi.phys.virginia.edu/HTW//microwave_ovens .html
Would this provide a low energy means of creating the plasma required
for ion engines? One means of creating the required plasma is by
irradiating the propellent gas with intense laser or x-ray beams to
strip off the electrons of the atoms of the gas, producing an ionized
plasma. However, these are both high-frequency forms of EM radiation
and therefore require high energy to produce. Microwaves being longer
wavelengths require less energy to produce.
Another means that is actually used for the Deep Space 1 probe is to
use electrons emitted by a cathode to irradiate the gas, ionizing it.
How does the energy requirement for the heating element of a cathode
compare to the energy requirement for producing the microwaves?
If this can be exploited as a low energy means of producing plasmas
then this might be used not only for low thrust engines as on DS 1 but
also for lauching ships into space by beaming the microwaves into a
reaction chamber of a rocket lined with, er, grapes.
--
________________________________________________
"In order for a scientific revolution to occur,
most scientists have to be wrong"
-- Bob Clark
________________________________________________
Another recent story discusses the applications of using cold plasmas:
Force Fields and 'Plasma' Shields Get Closer to Reality,
http://www.space.com/businesstechnology/technology /cold_plasma_000724.html
An advantage of the cold plasmas is the low power required to generate
them. However the article mentions that hot plasmas can be generated
with higher densities. Perhaps the microwave plasma generation method
can match the efficiency of the cold generation system while allowing
the high densities of the hot plasmas.
From: Robert Clark (rgregoryclark@yahoo.com)
Subject: Plasma propulsion for access to space?
Newsgroups: sci.astro, sci.physics, sci.space.policy, rec.arts.sf.science
Date: 2002-11-05 21:21:09 PST
http://groups.google.com/groups?th=87680963df54e46 c
Bob Clark
And if microorganisms can exist in comets, all bets are off:
From: Robert Clark (rgclark@my-deja.com)
Subject: Bioluminescent bacteria in comets?
Newsgroups: sci.astro, sci.space.policy, sci.astro.seti
Date: 2001-03-05 12:48:18 PST
The post copied below dicussed the theory of Hoyle and Wickramasinghe that
influenza comes from comets. This might find support in the curious glowing
trails found during the Leonid meteor showers:
Lasers Brings Leonids Alive
http://www.spacedaily.com/news/leonid-99c.html
"According to Dr. Jack Drummond, the laboratory's Directed Energy
Directorate astronomer, the Leonid meteors leave behind trails which, unlike
ordinary meteors that fade in a matter of seconds, can last up to an hour
and are still unexplained.
"I call these lingering meteor trails 'glowworms in the sky' since they are
not only visible for minutes by chemical reactions, but are twisted by the
winds into serpentine shapes, appearing like snakes or worms,' Drummond
explained."
The trails have been found to be peculiar to the 33 year periodic Leonid
storm periods:
"The scientists hope to answer why the 'glowworms' are peculiar to the
Leonid storm periods, which occur every 33 years, and why they are rarely
seen at other times. They wonder if it may imply something about the
composition of the parent comet."
As the page describes them:
"The glow, called chemiluminescence, is the production of light from
chemical reactions similar to bioluminescence, the same kind of glowing
reaction found in biological entities such as fireflies and their larvae,
glowworms."
However, if it is true that comets can contain microorganisms then perhaps
these glowing trails are in fact due to bioluminescence in bacteria. Then
the reason they appear during the 33 year storm periods could be because the
Earth is closest to the parent comet during these times and the bacteria
more easily survive the transfer to Earth.
Bioluminescent bacteria are known to produce their light when they are
disturbed:
Blazing a trail
http://www.newscientist.com/ns/19991120/blazing
Then the light in the Leonid trails could be triggered by the turbulence in
the air as the meteoroids streak through the atmosphere.
Most bioluminescence is of the blue-green color. This would be one thing to
check for. Another would be the spectroscopic signature of the molecules
that produce bioluminescence.
-snip-
From sci.astro:
s to ries/20010302/489917.html
t h/ flu_in_space_000121.html
1 0o ct_1.htm
1 0o ct_1.htm
0 00 _sr_final.html
k yw itness.html
8 EM %26P...82..149L
t h/ flu_in_space_000121.html
o gy _001115.html
From: Robert Clark (rgclark@my-deja.com)
Subject: Sunspot correlation to influenza confirmed.
Newsgroups: sci.astro, sci.space.policy, sci.astro.seti
Date: 2001-03-05 11:04:20 PST
Found this on Slashdot.com:
Flu epidemics coincide with solar eruptions, B.C. study says
You're coughing, you're sneezing, you think you've just got the flu, but you
could be a victim of sunspots
http://www.nationalpost.com/home/story.html?f=/
Some possible causes are a connection between flu epidemics and weather
which is known to be effected by sunspots or possibly the increase in
radiation during high sunspot periods damages the human immune system.
However, Hoyle and Wickramasinghe had noted this correlation earlier and
used this to support their idea that influenza comes from comets:
The Dilemma Of Influenza
http://www.spacedaily.com/news/life-00d.html
"Peaks of solar activity will undoubtedly assist in the descent of charged
molecular aggregates (including viruses) from the stratosphere to ground
level. Thus according to our present point of view serious influenza
epidemics would follow such peaks, provided the culprit molecular aggregates
were recently dispersed in the stratosphere from cometary meteor streams.
With a more or less regular occurrence of such meteor showers the limiting
condition may then be seen as the intensity of solar activity, leading
naturally to coincidences between the timings of pandemics or major
epidemics and sunspot peaks."
Germs from Outer Space! Researchers Say Flu Bugs Rain Down from Beyond
http://www.space.com/scienceastronomy/planetear
In this page, the H & W theory was criticized for suggesting the higher
solar radiation could lead to more influx of cometary material:
"There is scant evidence of any science going on here," said Stanford
University physicist Christopher Barrington-Leigh, who studies the upper
atmosphere and lower ionosphere. "According to the authors, solar activity
'will undoubtedly assist in the descent of charged molecular aggregates,'
but this is unphysical and unfounded."
However, there is evidence that increased solar radiation can increase the
numbers of visible meteroids in the Leonid meteor showers:
Meteor Storm Science: A 301 Explantion
by Robert McNaught
Canberra - November 16, 1999
http://www.spacedaily.com/news/leonid-99h.html
"We know the solar wind has some influence on the particles producing visual
meteors. The radiation counteracts the Sun's gravitational attraction, so
particles orbit the Sun more slowly. This is why storms occur in years
shortly after passage of the parent comet. The exact time lag for the main
bulk of the particles depends on the range of masses and ejection
velocities, and the number of orbital revolutions before encounter."
McNaught along with Asher produced the most widely accepted theory for
predicting the occurrence of the Leonids. Asher credits a theory of Lyytinen
and van Flandern for including the effects of radiation pressure in
predicting the timing and intensity of the Leonids:
The Moonlit Leonids 2000
http://www.spacescience.com/headlines/y2000/ast
"They've done some interesting work on the effect of radiation forces in
dispersing meteoroids," says Asher of Lyytinen and van Flandern, "and their
predictions could well turn out to be correct. If pushed, I would go with
our lower estimates of 100 per hour."
It is interesting to note that the Leonid display for 2000 did turn out to
be within the higher range predicted by Lyytinen and van Flandern using the
effects of radiation pressure:
The Moonlit Leonids 2000
http://www.spacescience.com/headlines/y2000/ast
"This year's likely encounters with dust streams are tabulated below. The
higher estimates for Leonid meteor rates, in the range 200 to 700 per hour,
come from astronomers Esko Lyytinen and Tom van Flandern, who are analyzing
the streams in much the same fashion as Asher and McNaught have done."
Leonids 2000 Special Report
http://www.space.com/scienceastronomy/leonids_2
18 November 2000 results
"Activity began to increase November 17 at 10:00 p.m. UT, according to the
International Meteor Organization (IMO). Starting around 1:30 a.m. UT on the
18th, a rate of 200 meteors per hour was observed. This rose to a peak of
about 300 per hour around 3:45 a.m. UT.
"Individual reports indicate during a second peak, for which the Eastern
United States was the prime viewing location, the hourly rate jumped to 120
to 180, and higher in brief stretches.
"Short bursts produced reports of an hourly rate as high 450."
However, it should be noted that the Lyytinen and van Flandern prediction
used van Flandern's controversial theory that comets are in fact debris
clouds orbiting asteroids:
Skywitness: The Leonid Meteor Storm From Girne, Cyprus
http://www.discovery.com/guides/space/leonids/s
Their work has appeared in a peer-reviewed journal:
Predicting the Strength of Leonid Outbursts
Earth, Moon, and Planets, v. 82/83, p. 149-166 (1998)
http://adsabs.harvard.edu/cgi-bin/bib_query?199
I don't know whether the same result could be obtained by including the
effects of radiation pressure with the standard model of comet composition
(in the interview on the "Skywitness: The Leonid Meteor Storm From Girne,
Cyprus" page, van Flandern claims that it can not.)
The predictions for the November 2001 Leonids by Asher & McNaught and by
Lyytinen & van Flandern are markedly different, which should provide a good
test of the accuracy of their respective models:
Predictions of upcoming Leonid activity, peak rates, and time of the peak.
http://web99.arc.nasa.gov/~leonid/1998.html
There is a difference between the effects of radiation pressure Hoyle and
Wickramasinghe are claiming from that of the Lyytinen & van Flandern model,
in that H & W seem to be saying higher radiation pressure would increase the
influx of cometary material already surrounding the Earth, whereas Lyytinen
& van Flandern seem to be only discussing the perturbations of cometary
material as the comet orbits the Sun, which would effect where and when the
Earth would meet the densest cometary streams. Note for example that by
including the effects of radiation pressure Lyytinen & van Flandern predict
a lower Leonid intensity for 2001 than does the Asher & McNaught model, as
shown in the tables in the "Predictions of upcoming Leonid activity, peak
rates, and time of the peak" page. However, note that the correlation
between flu outbreaks and solar activity is not exact. It may be that
determining the effect of solar radiation on cometary streams could provide
a more accurate correlation.
Another criticism of the H & W influenza theory is that the amounts of
infalling cometary material would be too small to cause the effects H & W
claim:
Germs from Outer Space! Researchers Say Flu Bugs Rain Down from Beyond
http://www.space.com/scienceastronomy/planetear
"Matthew Genge, of the Department of Mineralogy at the London Natural
History Museum, has estimated the amount of comet dust that survives entry
into the lower atmosphere, and thus how frequently an average-sized human
might be struck.
"Genge figures that if you live to be 5,000 years old, you'll likely
encounter one comet dust particle. Were it to harbor a virus, you would
presumably have to inhale the particle, further reducing the odds of
infection."
However, recent research shows more cometary material than previously
thought can survive the plunge through the atmosphere:
Leonid Meteor Shower: Sowing the Seeds of Life?
http://www.space.com/searchforlife/leonids_biol
"Other researchers have shown that meteors both small and large do not heat
up as much as previously thought, allowing the possibility that dormant life
could arrive on an incoming space rock or, just possibly, embedded in the
dust grain of a comet."
Bob Clark
"Atom holography is another stunning idea. Instead of making an image in light as done in conventional holography, atom optics would make the hologram of atoms. "
"Atom holography would create actual replicas, rather than images of light."
"What this means is, we could make a real, 3-dimensional replica of some object. We could copy objects." Meystre said.
"All of the individual steps to do this with nonlinear atom optics have been demonstrated. It's just a matter of making it work all together. I think it will happen in the next two or three years."
Whoa! Sounds like a transporter!
"Gah. I'm not the type to flame somebody for their grammar, but good god... What kind of sentence is this? What you thinking were?"
My sigfile goes, "The more harshly you criticize someone else, the more likely you are to be wrong yourself."
If is legitimate to say "What do you think the odds are?" then since the prepositional phrase "of Google acquiring such data" modifies the word "odds", the sentence as written is also legitimate.
Bob Clark
Don't give up hope yet:
TABLETOP LASER ACCELERATORS ARE BRIGHTER AND FASTER
Physics News 510, November 1, 2000
http://newton.ex.ac.uk/aip/physnews.510.html
Table-Top Fusion
Significant Physics on a Small Scale
Creating fusion used to be best left to suns and high-priced devices. Now scientists have managed it with a mere million-dollar machine.
http://www.abcnews.go.com/sections/science/Dail
Yankee Ingenuity: Dartmouth Physicists Convert A Microcope Into A Free-Electron Laser
http://www.sciencedaily.com/releases/1998/11/98
Such "tabletop" accelerators are currently in the million dollar range. But given the interest of physicists to make use of such devices, the cost will probably in the 10 to 100 thousand dollar range within 10-20 years.
Bob Clark
Here's the reformatted post:
n ce/standard_model_0102 08.html
Forum: sci.physics
Subject: New muon anomaly - implication for relativity.
Date: 02/09/2001
Author: Robert Clark
The recent measurement of the magnetic moment of the muon has been interpreted as a possible suggestion of supersymmetry:
'Milestone' Study Challenges Basic Laws of Physics, Universe,
http://www.space.com/scienceastronomy/generalscie
The paper on the research is available on the experiments home page:
The Muon g-2 Experiment Home Page,
http://phyppro1.phy.bnl.gov/g2muon/index.shtml
However, as discussed in the article on Space.com the measurements are dependent on special relativity. There were measurements of the decay of muons as a test of special relativity in the 70's. They supported special relativity within the precision of the measurements, that is, the errors were within the accuracy of the experiments. This new research can be interpreted as providing a more precise test of special relativity.
In my opinion, the approximate nature of special relativity, that is, Lorentz invariance, for real physical bodies is inherent in the mathematics of modern physics, both in quantum field theory and in general relativity. It is interesting to note that quantum electrodynamics which attempts to meld quantum mechanics with special relativity is very accurate when applied to the hydrogen atom but less so when applied to heavier atoms. These new measurements also show that QED while accurate for the light electron is less accurate when applied to the heavier muon.
The approximate nature of Lorentz invariance is discussed in a preprint by Jacobson and Mattingly:
"There is also reason to doubt exact Lorentz invariance: it leads to divergences in quantum field theory associated with states of arbitrarily high energy and momentum. This problem can be cured with a short distance cutoff which, however, breaks Lorentz invariance.
"For these reasons we entertain the possibility that there is a preferred rest frame at each space-time point. In particular, we seek a viable effective field theory incorporating a breaking of local Lorentz invariance."
Spontaneously broken Lorentz symmetry and gravity, p. 1,
http://xxx.lanl.gov/abs/gr-qc/0007031
Note also that if it is confirmed that Lorentz invariance is only an approximation, then that strongly implies that light speed can be exceeded at sufficiently high energies:
Forum: sci.astro
Subject: Superluminal speeds as an explanation of cosmic ray anomalies.
Date: 11/17/2000
Author: Robert Clark
http://x74.deja.com/getdoc.xp?AN=694810422
--
______________________________________
"The more harshly you criticize someone else,
the more likely you are to be wrong yourself.
The cause is a mystery..."
-- Bob Clark
______________________________________
I forgot to hit the "post as text" box, which is why the post is badly formatted. I considered reposting but readers of this site are so averse to repeating the same info.
1 .h tml
Thanks for the info and the ref. to the paper. I'll check that out. I would also be interested in finding out how your group can interpret these new results as a test of Lorentz invariance.
I also just saw a news release on some research that suggests the speed of light might vary and be frequency dependent over cosmological distances. It was meant to address the conumdrum of the anomalous gamma ray detection from Markarian 501 that was discussed in one of the articles I cited. One of the co-researchers is the highly-regarded general relativity theorist John Ellis:
Einstein in need of update?
http://www.eurekalert.org/releases/tam-ein02090
Space-Time Foam Effects on Particle Interactions and the GZK Cutoff
http://xxx.lanl.gov/abs/hep-th/0012216
The argument I'm presenting was taken from some debates I had on the sci.physics.relativity group a couple of years ago. Unfortunately, dejanews.com doesn't archive posts very far back anymore so those are no longer available.
A key point is philosophical/heuristic:
Is it reasonable that an equation of physics should be considered to be *exactly* true for the entire future of physics? Since we are not at the stage of having a final theory I don't think that is likely. However, note that the key idea that reaching and exceeding the speed of light would require infinite energy is based on the idea that the Lorentz transformation is *exactly* true, for if not you don't get the infinity by having a zero in the denominator.
One might argue that in the future Lorentz invariance will be replaced by a more accurate expression, but if it will not be *exactly* true at that time, surely it is not *exactly* true now.
I repeated this argument recently also in sci.physics.relativity and received the response that the conservation of energy is a counterexample to the idea that a physical equation should not be considered to be exactly true. However, remarkably, even conservation of energy is dependent on Einstein's transformation equations, so that deviations from these will also have an effect on how we interpret the conservation of energy. This is discussed in one of the papers that discuss violations of Lorentz invariance. I'll give you a reference if you like. The possibility that conservation of energy might also be violated is probably even a more jarring idea than that of violations of Lorentz invariance.
The mathematical reasons for doubting exact Lorentz invariance *for real physical bodies* are these:
The equations of both quantum field theory and general relativity have been found to be analogous to those of fluid mechanics. In fluid mechanics we also have the fact that for the approximate linear PDEs describing the fluid, exceeding the wave speed of the underlying medium would result in an infinite pressure. Naively, one might conclude no body can exceed the speed of sound in a medium. But of course mathematicians and engineers know these equations are approximations. These linear PDEs need to be replaced by the more accurate nonlinear PDE's that describe the fluid in transonic and supersonic situations.
One might take this to be just a coincidence that the most advanced equations of modern physics, quantum field theory and general relativity, both describe the vacuum with equations that are analogous to those of a material medium. But the predictions of those theories are also what one would expect for a medium. In quantum electrodynamics and quantum field theory in general we have the fact that you must make mass and charge renormalizations to describe the reactions of subatomic particles very close to the intense field of the nucleus.
The key fact about this in regard to this discussion is this: if Lorentz invariance is to be true, then *every* aspect of its predictions must hold, not just simply time transformations as measured by decay rates. If the *intrinisic* mass and charge have to changed when moving at high speeds close to the nucleus, then that signals Lorentz invariance is not holding in that situation. (Note this is not the "relativistic mass" change, and of course for Lorentz invariance to hold, charge must be invariant.)
One might say this is only true for subatomic particles close to the nucleus, but the equations of QED show in fact *this is true for a field of any intensity*, the corrections are just extremely small. This is discussed in papers describing how the speed of light is altered in regions of strong electrical and magnetic fields, which in itself is telling you that the vacuum has properties dependent on the energy content in a region that effect the *intrinisic* properties of bodies in that region.
When I had this discussion on sci.physics.relativity there was a fundamentally important fact about this being overlooked: not only do mass and charge renormalizations have to be made close to the nucleus, but THE DEVIATIONS IN MASS AND CHARGE GET WORSE AS THE SPEED OF THE PARTICLE INCREASES. I can not overemphasize the importance of this fact to the argument. As I said before the mass and charge renomalizations are signals of the failure of Lorentz invariance in these situations. That the deviations get worse with speed means the deviation from Lorentz invariance gets worse with speed. This is exactly what you would expect if it were true that this is analogous to the situation of a body traveling through a material medium and that given sufficient energy you can exceed the wave speed of the medium.
As I said the mathematics of general relativity also suggests Lorentz invariance should only be an approximation *for real physical bodies*. In general relativity is it said Lorentz invariance holds only "locally". This is defined to mean it only holds *at a point*, or equivalently it holds on a tangent plane. But in differential geometry on which GR is based, a property is said to hold locally, when it holds *exactly* on a small region of the manifold. According to differential geometry which is the mathematical theory deriving GR, Lorentz invariance does not hold locally using the definition used in that theory and in every field of mathematics that uses the concept of a manifold. In the primary reference work on GR _Gravitation_ by Wheeler, Misner and Thorne it says explicitly that in real space with curvature, containing real bodies inducing their own space-time curvature Minkowski space can not be expected to exactly hold. To me this is saying that Lorentz invariance does not hold exactly for real physical bodies in real space with curvature.
In the debates on sci.physics.relativity I only gave a heuristic reason that I think can probably be made rigorous that the fundamentally important fact that the deviations from Lorentz invariance get worse as the speed of the body increases also holds in general relativity: the fact that the effective "force" a body feels becomes greater as the speed of the body increases (this is discussed in the FAQ for the sci.physics.relativity group.) This suggests that the *intrinsic* mass of the body is increasing with speed. (Again this is not the "relativistic mass" correction.) However, I found an article in the American Journal of Physics that says this explicitly:
American Journal of Physics -- July 1985 -- Volume 53, Issue 7, pp. 661-663
Measuring the active gravitational mass of a moving object
D. W. Olson and R. C. Guarino
Department of Physics, Southwest Texas State University, San Marcos, Texas 78666
If a heavy object with rest mass M moves past you with a velocity comparable to the speed of light, you will be attracted gravitationally towards its path as though it had an increased mass. If the relativistic increase in active gravitational mass is measured by the transverse (and longitudinal) velocities which such a moving mass induces in test particles initially at rest near its path, then we find, with this definition, that Mrel=gamma(1+beta^2)M. Therefore, in the ultrarelativistic limit, the active gravitational mass of a moving body, measured in this way, is not gammaM but is approximately 2gammaM.
Note this "effective" mass of the body in a gravitational field is again not the simple "relativistic mass". To me this is again signaling that Lorentz invariance is only an approximation for real physical bodies.
Another article in AJP that appears to be saying this is by Steve Carlip:
American Journal of Physics -- May 1998 -- Volume 66, Issue 5, pp. 409-413
Kinetic energy and the equivalence principle
S. Carlip
Department of Physics, University of California, Davis, California 95616
According to the general theory of relativity, kinetic energy contributes to gravitational mass. Surprisingly, the observational evidence for this prediction does not seem to be discussed in the literature. I reanalyze existing experimental data to test the equivalence principle for the kinetic energy of atomic electrons, and show that fairly strong limits on possible violations can
be obtained. I discuss the relationship of this result to the occasional claim that "light falls with twice the acceleration of ordinary matter."
However, I'm only judging here by the abstract as I haven't had the chance to read this article yet. I also hasten to add that Dr. Carlip is a frequent contributor to the sci.physics.relativity group in which he argues against speeds surpassing the speed of light, so he would probably be opposed to the idea that Lorentz invariance is only an approximation.
These articles can be found by searching on AJP's site: http://ojps.aip.org/ajp/
Note I am suggesting that high speeds and energy content in a region can effect what are regarded as intrinsic properties. This of course implies these properties really are not intrinsic but are dependent on surrounding conditions. My view is that properties such as mass and charge will be found to be tensors dependent on the mass/energy distribution in their vicinity and indeed on that of the universe.
Bob Clark