Sunday May 20, 2012
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Pentcho replied to the topic Re: Chemomechanical Transduction and the Second Law in the forums.
Another device that channels ambient heat into other forms of energy:
physics.aps.org/synopsis-for/10.1103/PhysRevLett.108.097403
"Physicists have known for decades that, in principle, a semiconductor device can emit more light power than it consumes electrically. Experiments published in Physical Review Letters finally demonstrate this in practice, though at a small scale. (...) Decreasing the input power to 30 picowatts, the team detected nearly 70 picowatts of emitted light. The extra energy comes from lattice vibrations, so the device should be cooled slightly, as occurs in thermoelectric coolers. These initial results provide too little light for most applications. However, heating the light emitters increases their output power and efficiency, meaning they are like thermodynamic heat engines..."
physicsworld.com/cws/article/news/48882
"At first glance this conversion of waste heat to useful photons could appear to violate fundamental laws of thermodynamics, but lead researcher Parthiban Santhanam of the Massachusetts Institute of Technology explains that the process is perfectly consistent with the second law of thermodynamics. "The most counterintuitive aspect of this result is that we don't typically think of light as being a form of heat. Usually we ignore the entropy and think of light as work," he explains. "If the photons didn't have entropy (i.e. if they were a form of work, rather than heat), this would break the second law. Instead, the entropy shows up in the outgoing photons, so the second law is satisfied."
The light-is-not-work argument formally saves the second law of thermodynamics in this particular case but still the faith is undermined.
Pentcho Valev
pvalev@yahoo.com
physics.aps.org/synopsis-for/10.1103/PhysRevLett.108.097403
"Physicists have known for decades that, in principle, a semiconductor device can emit more light power than it consumes electrically. Experiments published in Physical Review Letters finally demonstrate this in practice, though at a small scale. (...) Decreasing the input power to 30 picowatts, the team detected nearly 70 picowatts of emitted light. The extra energy comes from lattice vibrations, so the device should be cooled slightly, as occurs in thermoelectric coolers. These initial results provide too little light for most applications. However, heating the light emitters increases their output power and efficiency, meaning they are like thermodynamic heat engines..."
physicsworld.com/cws/article/news/48882
"At first glance this conversion of waste heat to useful photons could appear to violate fundamental laws of thermodynamics, but lead researcher Parthiban Santhanam of the Massachusetts Institute of Technology explains that the process is perfectly consistent with the second law of thermodynamics. "The most counterintuitive aspect of this result is that we don't typically think of light as being a form of heat. Usually we ignore the entropy and think of light as work," he explains. "If the photons didn't have entropy (i.e. if they were a form of work, rather than heat), this would break the second law. Instead, the entropy shows up in the outgoing photons, so the second law is satisfied."
The light-is-not-work argument formally saves the second law of thermodynamics in this particular case but still the faith is undermined.
Pentcho Valev
pvalev@yahoo.com
8 hours ago
Pentcho created a new topic Photons Slowed Down by Vacuum in the forums.
www.physorg.com/news/2011-11-scientists-vacuum.html
"In fact, the vacuum is full of various particles that are continuously fluctuating in and out of existence. They appear, exist for a brief moment and then disappear again. Since their existence is so fleeting, they are usually referred to as virtual particles."
www.physorg.com/news/2011-06-physics-einstein.html
"...space should be grainy at the smallest scales, like sand on a beach. (...) According to calculations, the tiny grains would affect the way that gamma rays travel through space."
bourabai.narod.ru/shtyrkov/evolution.htm
"At present it is ascertained that vacuum is not an "empty space" - rather, it is a certain material continuum with quite definite although still unknown properties. This has been confirmed by observation of vacuum effects such as "zero-oscillations", vacuum polarization, particle generation by electromagnetic interactions. Therefore it is reasonable to suggest that physical vacuum could have internal friction due to its own small but real viscosity, which in the end produces redshift. (...) ...the differential equation for the speed of light dc/dt=-Ho*c(t)"
HYPOTHESIS: As the photon travels through space (in a STATIC universe), it bumps into "virtual particles" or "tiny grains" and as a result loses speed in much the same way that a golf ball loses speed due to the resistance of the air.
On this hypothesis the resistive force (Fr) is proportional to the the velocity of the photon (V):
Fr = - KV
That is, the speed of light decreases with time in accordance with the equation:
dV/dt = - K'V
Clearly, at the end of a very long journey of photons (coming from a very distant object), the contribution to the redshift is much smaller than the contribution at the beginning of the journey. Light coming from nearer objects is less subject to this difference, that is, the increase of the redshift with distance is closer to LINEAR for short distances. For distant light sources we have:
f' = f(exp(-kt))
where f is the original and f' the measured (redshifted) frequency. (The analogy with the golf ball requires that it be assumed that the speed of light and the frequency vary while the wavelength remains unchanged.) For short distances the following approximations can be made:
f' = f(exp(-kt)) ~ f(1-kt) ~ f - kd/L
where d is the distance between the light source and the observer and L is the wavelength. The equation f'=f-kd/L is only valid for short distances and corresponds to the Hubble law whereas the equation f'=f(exp(-kt)), by showing that later contributions to the redshift are smaller than earlier ones, provides an alternative explanation, within the framework of a STATIC universe, of the observations that brought the 2011 Nobel Prize for Physics to Saul Perlmutter, Adam Riess and Brian Schmidt. The analogy with the golf ball suggests that, at the end of a very long journey (in a STATIC universe), photons redshift much less vigorously than at the beginning.
Pentcho Valev
pvalev@yahoo.com
"In fact, the vacuum is full of various particles that are continuously fluctuating in and out of existence. They appear, exist for a brief moment and then disappear again. Since their existence is so fleeting, they are usually referred to as virtual particles."
www.physorg.com/news/2011-06-physics-einstein.html
"...space should be grainy at the smallest scales, like sand on a beach. (...) According to calculations, the tiny grains would affect the way that gamma rays travel through space."
bourabai.narod.ru/shtyrkov/evolution.htm
"At present it is ascertained that vacuum is not an "empty space" - rather, it is a certain material continuum with quite definite although still unknown properties. This has been confirmed by observation of vacuum effects such as "zero-oscillations", vacuum polarization, particle generation by electromagnetic interactions. Therefore it is reasonable to suggest that physical vacuum could have internal friction due to its own small but real viscosity, which in the end produces redshift. (...) ...the differential equation for the speed of light dc/dt=-Ho*c(t)"
HYPOTHESIS: As the photon travels through space (in a STATIC universe), it bumps into "virtual particles" or "tiny grains" and as a result loses speed in much the same way that a golf ball loses speed due to the resistance of the air.
On this hypothesis the resistive force (Fr) is proportional to the the velocity of the photon (V):
Fr = - KV
That is, the speed of light decreases with time in accordance with the equation:
dV/dt = - K'V
Clearly, at the end of a very long journey of photons (coming from a very distant object), the contribution to the redshift is much smaller than the contribution at the beginning of the journey. Light coming from nearer objects is less subject to this difference, that is, the increase of the redshift with distance is closer to LINEAR for short distances. For distant light sources we have:
f' = f(exp(-kt))
where f is the original and f' the measured (redshifted) frequency. (The analogy with the golf ball requires that it be assumed that the speed of light and the frequency vary while the wavelength remains unchanged.) For short distances the following approximations can be made:
f' = f(exp(-kt)) ~ f(1-kt) ~ f - kd/L
where d is the distance between the light source and the observer and L is the wavelength. The equation f'=f-kd/L is only valid for short distances and corresponds to the Hubble law whereas the equation f'=f(exp(-kt)), by showing that later contributions to the redshift are smaller than earlier ones, provides an alternative explanation, within the framework of a STATIC universe, of the observations that brought the 2011 Nobel Prize for Physics to Saul Perlmutter, Adam Riess and Brian Schmidt. The analogy with the golf ball suggests that, at the end of a very long journey (in a STATIC universe), photons redshift much less vigorously than at the beginning.
Pentcho Valev
pvalev@yahoo.com
1 day ago
Pentcho replied to the topic Re: Chemomechanical Transduction and the Second Law in the forums.
Chemical reactions are not true donors of energy when mechanical work is produced. A close inspection shows that they only channel the ambient heat into other forms of energy. Zihan Xu et al. seem to have found a way to get rid of the chemical-reaction camouflage accompanying the conversion of ambient heat into work:
arxiv.org/abs/1203.0161
Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment, Zihan Xu et al: "Moreover, the thermal velocity of ions can be maintained by the external environment, which means it is unlimited. However, little study has been reported on converting the ionic thermal energy into electricity. Here we present a graphene device with asymmetric electrodes configuration to capture such ionic thermal energy and convert it into electricity. (...) To exclude the possibility of chemical reaction, we performed control experiments... (...) In conclusion, we could not find any evidences that support the opinion that the induced voltage came from chemical reaction. The mechanism for electricity generation by graphene in solution is a pure physical process..."
arxiv.org/abs/1204.6688
"Graphene can collect energy from the ambient heat and convert it to electricity, which makes it an ideal candidate for the fabrication of self-powered devices. However, this technology is suffering the high cost, which limits the practical use of it. In this work, we demonstrated that the cost can be reduced by using low cost reduced graphene oxide (RGO), graphite electrodes and low cost glass substrates. The results showed that this technology can be of practical value for the "battery" industry."
Pentcho Valev
pvalev@yahoo.com
arxiv.org/abs/1203.0161
Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment, Zihan Xu et al: "Moreover, the thermal velocity of ions can be maintained by the external environment, which means it is unlimited. However, little study has been reported on converting the ionic thermal energy into electricity. Here we present a graphene device with asymmetric electrodes configuration to capture such ionic thermal energy and convert it into electricity. (...) To exclude the possibility of chemical reaction, we performed control experiments... (...) In conclusion, we could not find any evidences that support the opinion that the induced voltage came from chemical reaction. The mechanism for electricity generation by graphene in solution is a pure physical process..."
arxiv.org/abs/1204.6688
"Graphene can collect energy from the ambient heat and convert it to electricity, which makes it an ideal candidate for the fabrication of self-powered devices. However, this technology is suffering the high cost, which limits the practical use of it. In this work, we demonstrated that the cost can be reduced by using low cost reduced graphene oxide (RGO), graphite electrodes and low cost glass substrates. The results showed that this technology can be of practical value for the "battery" industry."
Pentcho Valev
pvalev@yahoo.com
1 day ago
Pentcho created a new topic Chemomechanical Transduction and the Second Law in the forums.
www.ncbi.nlm.nih.gov/pmc/articles/PMC136...ophysj00645-0017.pdf
POLYELECTROLYTES AND THEIR BIOLOGICAL INTERACTIONS, A. KATCHALSKY, pp. 13-15: "Let the polymolecule be a negatively charged polyacid in a stretched state and have a length L. Now let us add to the molecule a mineral acid to provide hydrogen ions to combine with the ionized carboxylate groups and transform them into undissociated carboxylic groups according to the reaction RCOO- + H+ = RCOOH. By means of this reaction, the electrostatic repulsion which kept the macromolecule in a highly stretched state vanishes and instead the Brownian motion and intramolecular attraction cause a coiling up of the polymeric chains. Upon coiling, the polymolecule contracts and lifts the attached weight through a distance deltaL. On lifting the weight, mechanical work f*deltaL was performed... (...) FIGURE 4: Polyacid gel in sodium hydroxide solution: expanded. Polyacid gel in acid solution: contracted; weight is lifted."
data.epo.org/publication-server/pdf-docu...209&iepatch=.pdf
Dan Urry, p. 14: "When the pH is lowered (that is, on raising the chemical potential, mu, of the protons present) at the isothermal condition of 37°C, these matrices can exert forces, f, sufficient to lift weights that are a thousand times their dry weight. This is chemomechanical transduction..."
It can rigorously be proved that the chemomechanical transduction described by Katchalsky and Urry does violate the second law of thermodynamics but even a cursory glance would suggest that anti-second-law behaviour is very likely. The work-producing force of contraction increases as hydrogen ions chemically react with the contractile macromolecule but the chemical reaction is spontaneous and, per se, does not consume work. (In a rigorous treatment, the work involved in adding and removing the mineral acid has to be evaluated).
Pentcho Valev
pvalev@yahoo.com
POLYELECTROLYTES AND THEIR BIOLOGICAL INTERACTIONS, A. KATCHALSKY, pp. 13-15: "Let the polymolecule be a negatively charged polyacid in a stretched state and have a length L. Now let us add to the molecule a mineral acid to provide hydrogen ions to combine with the ionized carboxylate groups and transform them into undissociated carboxylic groups according to the reaction RCOO- + H+ = RCOOH. By means of this reaction, the electrostatic repulsion which kept the macromolecule in a highly stretched state vanishes and instead the Brownian motion and intramolecular attraction cause a coiling up of the polymeric chains. Upon coiling, the polymolecule contracts and lifts the attached weight through a distance deltaL. On lifting the weight, mechanical work f*deltaL was performed... (...) FIGURE 4: Polyacid gel in sodium hydroxide solution: expanded. Polyacid gel in acid solution: contracted; weight is lifted."
data.epo.org/publication-server/pdf-docu...209&iepatch=.pdf
Dan Urry, p. 14: "When the pH is lowered (that is, on raising the chemical potential, mu, of the protons present) at the isothermal condition of 37°C, these matrices can exert forces, f, sufficient to lift weights that are a thousand times their dry weight. This is chemomechanical transduction..."
It can rigorously be proved that the chemomechanical transduction described by Katchalsky and Urry does violate the second law of thermodynamics but even a cursory glance would suggest that anti-second-law behaviour is very likely. The work-producing force of contraction increases as hydrogen ions chemically react with the contractile macromolecule but the chemical reaction is spontaneous and, per se, does not consume work. (In a rigorous treatment, the work involved in adding and removing the mineral acid has to be evaluated).
Pentcho Valev
pvalev@yahoo.com
1 day ago
Pentcho replied to the topic Re: Einsteiniana: No Understanding Is Necessary in the forums.
The "mystery of non-understanding" (the Michelson-Morley experiment has gloriously confirmed the constancy of the speed of light, Divine Einstein, yes we all believe in relativity, relativity, relativity):
www.amazon.com/Faster-Than-Speed-Light-S...lation/dp/0738205257
Faster Than the Speed of Light, Joao Magueijo: "A missile fired from a plane moves faster than one fired from the ground because the plane's speed adds to the missile's speed. If I throw something forward on a moving train, its speed with respect to the platform is the speed of that object plus that of the train. You might think that the same should happen to light: Light flashed from a train should travel faster. However, what the Michelson-Morley experiments showed was that this was not the case: Light always moves stubbornly at the same speed. This means that if I take a light ray and ask several observers moving with respect to each other to measure the speed of this light ray, they will all agree on the same apparent speed!"
www.pourlascience.fr/ewb_pages/f/fiche-a...relativite-26042.php
Marc Lachièze-Rey: "Mais au cours du XIXe siècle, diverses expériences, et notamment celle de Michelson et Morley, ont convaincu les physiciens que la vitesse de la lumière dans le vide est invariante. En particulier, la vitesse de la lumière ne s'ajoute ni ne se retranche à celle de sa source si celle-ci est en mouvement. Autrement dit, la lumière n'obéit pas à la loi d'additivité des vitesses de la cinématique newtonienne (héritée de Galilée). Or la cinématique est l'étude des mouvements de la matière libre de toute interaction, et qui ne dépendent donc que des propriétés de l'espace et du temps. L'invariance de la vitesse de la lumière entraînait donc une remise en cause des notions newtoniennes de temps et d'espace absolus, ce qu'Einstein fut le premier à reconnaître pleinement."
www.time.com/time/magazine/article/0,9171,993018,00.html
Stephen Hawking: "So if you were traveling in the same direction as the light, you would expect that its speed would appear to be lower, and if you were traveling in the opposite direction to the light, that its speed would appear to be higher. Yet a series of experiments failed to find any evidence for differences in speed due to motion through the ether. The most careful and accurate of these experiments was carried out by Albert Michelson and Edward Morley at the Case Institute in Cleveland, Ohio, in 1887......It was as if light always traveled at the same speed relative to you, no matter how you were moving."
The mystery of understanding (the Michelson-Morley experiment confirmed the variable speed of light predicted by Newton's emission theory of light, Divine Einstein, yes we all believe in relativity, relativity, relativity):
www.pitt.edu/~jdnorton/papers/companion.doc
John Norton: "These efforts were long misled by an exaggeration of the importance of one experiment, the Michelson-Morley experiment, even though Einstein later had trouble recalling if he even knew of the experiment prior to his 1905 paper. This one experiment, in isolation, has little force. Its null result happened to be fully compatible with Newton's own emission theory of light. Located in the context of late 19th century electrodynamics when ether-based, wave theories of light predominated, however, it presented a serious problem that exercised the greatest theoretician of the day."
philsci-archive.pitt.edu/1743/2/Norton.pdf
John Norton: "In addition to his work as editor of the Einstein papers in finding source material, Stachel assembled the many small clues that reveal Einstein's serious consideration of an emission theory of light; and he gave us the crucial insight that Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity. Even today, this point needs emphasis. The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE."
www.amazon.com/Relativity-Its-Roots-Bane...ffmann/dp/0486406768
"Relativity and Its Roots" By Banesh Hoffmann: "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."
Pentcho Valev
pvalev@yahoo.com
www.amazon.com/Faster-Than-Speed-Light-S...lation/dp/0738205257
Faster Than the Speed of Light, Joao Magueijo: "A missile fired from a plane moves faster than one fired from the ground because the plane's speed adds to the missile's speed. If I throw something forward on a moving train, its speed with respect to the platform is the speed of that object plus that of the train. You might think that the same should happen to light: Light flashed from a train should travel faster. However, what the Michelson-Morley experiments showed was that this was not the case: Light always moves stubbornly at the same speed. This means that if I take a light ray and ask several observers moving with respect to each other to measure the speed of this light ray, they will all agree on the same apparent speed!"
www.pourlascience.fr/ewb_pages/f/fiche-a...relativite-26042.php
Marc Lachièze-Rey: "Mais au cours du XIXe siècle, diverses expériences, et notamment celle de Michelson et Morley, ont convaincu les physiciens que la vitesse de la lumière dans le vide est invariante. En particulier, la vitesse de la lumière ne s'ajoute ni ne se retranche à celle de sa source si celle-ci est en mouvement. Autrement dit, la lumière n'obéit pas à la loi d'additivité des vitesses de la cinématique newtonienne (héritée de Galilée). Or la cinématique est l'étude des mouvements de la matière libre de toute interaction, et qui ne dépendent donc que des propriétés de l'espace et du temps. L'invariance de la vitesse de la lumière entraînait donc une remise en cause des notions newtoniennes de temps et d'espace absolus, ce qu'Einstein fut le premier à reconnaître pleinement."
www.time.com/time/magazine/article/0,9171,993018,00.html
Stephen Hawking: "So if you were traveling in the same direction as the light, you would expect that its speed would appear to be lower, and if you were traveling in the opposite direction to the light, that its speed would appear to be higher. Yet a series of experiments failed to find any evidence for differences in speed due to motion through the ether. The most careful and accurate of these experiments was carried out by Albert Michelson and Edward Morley at the Case Institute in Cleveland, Ohio, in 1887......It was as if light always traveled at the same speed relative to you, no matter how you were moving."
The mystery of understanding (the Michelson-Morley experiment confirmed the variable speed of light predicted by Newton's emission theory of light, Divine Einstein, yes we all believe in relativity, relativity, relativity):
www.pitt.edu/~jdnorton/papers/companion.doc
John Norton: "These efforts were long misled by an exaggeration of the importance of one experiment, the Michelson-Morley experiment, even though Einstein later had trouble recalling if he even knew of the experiment prior to his 1905 paper. This one experiment, in isolation, has little force. Its null result happened to be fully compatible with Newton's own emission theory of light. Located in the context of late 19th century electrodynamics when ether-based, wave theories of light predominated, however, it presented a serious problem that exercised the greatest theoretician of the day."
philsci-archive.pitt.edu/1743/2/Norton.pdf
John Norton: "In addition to his work as editor of the Einstein papers in finding source material, Stachel assembled the many small clues that reveal Einstein's serious consideration of an emission theory of light; and he gave us the crucial insight that Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity. Even today, this point needs emphasis. The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE."
www.amazon.com/Relativity-Its-Roots-Bane...ffmann/dp/0486406768
"Relativity and Its Roots" By Banesh Hoffmann: "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."
Pentcho Valev
pvalev@yahoo.com
2 days ago
Pentcho replied to the topic Re: Einsteiniana: No Understanding Is Necessary in the forums.
The "mystery of non-understanding": The youthfulness of the travelling twin both has nothing to do with the acceleration she has suffered and is entirely caused by the acceleration she has suffered:
www.people.fas.harvard.edu/~djmorin/book.html
Introduction to Classical Mechanics With Problems and Solutions, David Morin, Cambridge University Press, Chapter 11, p. 14: "Example (Twin paradox): Twin A stays on the earth, while twin B flies quickly to a distant star and back. Show that B is younger than A when they meet up again. (...) For the entire outward and return parts of the trip, B does observe A's clock running slow, but enough strangeness occurs during the turning-around period to make A end up older. Note, however, that a discussion of acceleration is not required to quantitatively understand the paradox, as Problem 11.2 shows."
www.damtp.cam.ac.uk/research/gr/members/...alRelativity2010.pdf
Gary W. Gibbons FRS: "In other words, by simply staying at home Jack has aged relative to Jill. There is no paradox because the lives of the twins are not strictly symmetrical. This might lead one to suspect that the accelerations suffered by Jill might be responsible for the effect. However this is simply not plausible because using identical accelerating phases of her trip, she could have travelled twice as far. This would give twice the amount of time gained."
www.informaworld.com/smpp/content~content=a909857880
Peter Hayes "The Ideology of Relativity: The Case of the Clock Paradox" : Social Epistemology, Volume 23, Issue 1 January 2009, pages 57-78: Albert Einstein wrote in 1911: "The [travelling] clock runs slower if it is in uniform motion, but if it undergoes a change of direction as a result of a jolt, then the theory of relativity does not tell us what happens. The sudden change of direction might produce a sudden change in the position of the hands of the clock. However, the longer the clock is moving rectilinearly and uniformly with a given speed in a forward motion, i.e., the larger the dimensions of the polygon, the smaller must be the effect of such a hypothetical sudden change."
www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/spacetime_tachyon/index.html
John Norton: "Then, at the end of the outward leg, the traveler abruptly changes motion, accelerating sharply to adopt a new inertial motion directed back to earth. What comes now is the key part of the analysis. The effect of the change of motion is to alter completely the traveler's judgment of simultaneity. The traveler's hypersurfaces of simultaneity now flip up dramatically. Moments after the turn-around, when the travelers clock reads just after 2 days, the traveler will judge the stay-at-home twin's clock to read just after 7 days. That is, the traveler will judge the stay-at-home twin's clock to have jumped suddenly from reading 1 day to reading 7 days. This huge jump puts the stay-at-home twin's clock so far ahead of the traveler's that it is now possible for the stay-at-home twin's clock to be ahead of the travelers when they reunite."
en.wikisource.org/wiki/Dialog_about_obje...theory_of_relativity
Dialog about Objections against the Theory of Relativity (1918), by Albert Einstein: "...according to the special theory of relativity the coordinate systems K and K' are by no means equivalent systems. Indeed this theory asserts only the equivalence of all Galilean (unaccelerated) coordinate systems, that is, coordinate systems relative to which sufficiently isolated, material points move in straight lines and uniformly. K is such a coordinate system, but not the system K', that is accelerated from time to time. Therefore, from the result that after the motion to and fro the clock U2 is running behind U1, no contradiction can be constructed against the principles of the theory. (...) During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4. This consideration completely clears up the paradox that you brought up."
Pentcho Valev
pvalev@yahoo.com
www.people.fas.harvard.edu/~djmorin/book.html
Introduction to Classical Mechanics With Problems and Solutions, David Morin, Cambridge University Press, Chapter 11, p. 14: "Example (Twin paradox): Twin A stays on the earth, while twin B flies quickly to a distant star and back. Show that B is younger than A when they meet up again. (...) For the entire outward and return parts of the trip, B does observe A's clock running slow, but enough strangeness occurs during the turning-around period to make A end up older. Note, however, that a discussion of acceleration is not required to quantitatively understand the paradox, as Problem 11.2 shows."
www.damtp.cam.ac.uk/research/gr/members/...alRelativity2010.pdf
Gary W. Gibbons FRS: "In other words, by simply staying at home Jack has aged relative to Jill. There is no paradox because the lives of the twins are not strictly symmetrical. This might lead one to suspect that the accelerations suffered by Jill might be responsible for the effect. However this is simply not plausible because using identical accelerating phases of her trip, she could have travelled twice as far. This would give twice the amount of time gained."
www.informaworld.com/smpp/content~content=a909857880
Peter Hayes "The Ideology of Relativity: The Case of the Clock Paradox" : Social Epistemology, Volume 23, Issue 1 January 2009, pages 57-78: Albert Einstein wrote in 1911: "The [travelling] clock runs slower if it is in uniform motion, but if it undergoes a change of direction as a result of a jolt, then the theory of relativity does not tell us what happens. The sudden change of direction might produce a sudden change in the position of the hands of the clock. However, the longer the clock is moving rectilinearly and uniformly with a given speed in a forward motion, i.e., the larger the dimensions of the polygon, the smaller must be the effect of such a hypothetical sudden change."
www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/spacetime_tachyon/index.html
John Norton: "Then, at the end of the outward leg, the traveler abruptly changes motion, accelerating sharply to adopt a new inertial motion directed back to earth. What comes now is the key part of the analysis. The effect of the change of motion is to alter completely the traveler's judgment of simultaneity. The traveler's hypersurfaces of simultaneity now flip up dramatically. Moments after the turn-around, when the travelers clock reads just after 2 days, the traveler will judge the stay-at-home twin's clock to read just after 7 days. That is, the traveler will judge the stay-at-home twin's clock to have jumped suddenly from reading 1 day to reading 7 days. This huge jump puts the stay-at-home twin's clock so far ahead of the traveler's that it is now possible for the stay-at-home twin's clock to be ahead of the travelers when they reunite."
en.wikisource.org/wiki/Dialog_about_obje...theory_of_relativity
Dialog about Objections against the Theory of Relativity (1918), by Albert Einstein: "...according to the special theory of relativity the coordinate systems K and K' are by no means equivalent systems. Indeed this theory asserts only the equivalence of all Galilean (unaccelerated) coordinate systems, that is, coordinate systems relative to which sufficiently isolated, material points move in straight lines and uniformly. K is such a coordinate system, but not the system K', that is accelerated from time to time. Therefore, from the result that after the motion to and fro the clock U2 is running behind U1, no contradiction can be constructed against the principles of the theory. (...) During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4. This consideration completely clears up the paradox that you brought up."
Pentcho Valev
pvalev@yahoo.com
3 days ago
Pentcho replied to the topic Re: Einsteiniana: No Understanding Is Necessary in the forums.
Divine Albert about the "mystery of non-understanding":
plus.maths.org/issue37/features/Einstein/index.html
John Barrow: "Einstein restored faith in the unintelligibility of science. Everyone knew that Einstein had done something important in 1905 (and again in 1915) but almost nobody could tell you exactly what it was. When Einstein was interviewed for a Dutch newspaper in 1921, he attributed his mass appeal to the mystery of his work for the ordinary person: "Does it make a silly impression on me, here and yonder, about my theories of which they cannot understand a word? I think it is funny and also interesting to observe. I am sure that it is the mystery of non-understanding that appeals to them...it impresses them, it has the colour and the appeal of the mysterious."
Pentcho Valev
pvalev@yahoo.com
plus.maths.org/issue37/features/Einstein/index.html
John Barrow: "Einstein restored faith in the unintelligibility of science. Everyone knew that Einstein had done something important in 1905 (and again in 1915) but almost nobody could tell you exactly what it was. When Einstein was interviewed for a Dutch newspaper in 1921, he attributed his mass appeal to the mystery of his work for the ordinary person: "Does it make a silly impression on me, here and yonder, about my theories of which they cannot understand a word? I think it is funny and also interesting to observe. I am sure that it is the mystery of non-understanding that appeals to them...it impresses them, it has the colour and the appeal of the mysterious."
Pentcho Valev
pvalev@yahoo.com
3 days ago
Pentcho created a new topic Einsteiniana: No Understanding Is Necessary in the forums.
www.phys.unsw.edu.au/einsteinlight/jw/module3_weird_logic.htm
Professor Joe Wolfe: "At this stage, many of my students say things like "The invariance of the speed of light among observers is impossible" or "I can't understand it". Well, it's not impossible. It's even more than possible, it is true. This is something that has been extensively measured, and many refinements to the Michelson and Morely experiment, and complementary experiments have confirmed this invariance to very great precision. As to understanding it, there isn't really much to understand. However surprising and weird it may be, it is the case. It's the law in our universe. The fact of the invariance of c doesn't take much understanding: what requires understanding are its consequences, and how it can be integrated into what we already know."
Needless to say, the Michelson-Morley experiment has not confirmed the invariance of the speed of light:
www.pitt.edu/~jdnorton/papers/companion.doc
John Norton: "These efforts were long misled by an exaggeration of the importance of one experiment, the Michelson-Morley experiment, even though Einstein later had trouble recalling if he even knew of the experiment prior to his 1905 paper. This one experiment, in isolation, has little force. Its null result happened to be fully compatible with Newton's own emission theory of light. Located in the context of late 19th century electrodynamics when ether-based, wave theories of light predominated, however, it presented a serious problem that exercised the greatest theoretician of the day."
philsci-archive.pitt.edu/1743/2/Norton.pdf
John Norton: "In addition to his work as editor of the Einstein papers in finding source material, Stachel assembled the many small clues that reveal Einstein's serious consideration of an emission theory of light; and he gave us the crucial insight that Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity. Even today, this point needs emphasis. The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE."
www.amazon.com/Relativity-Its-Roots-Bane...ffmann/dp/0486406768
"Relativity and Its Roots" By Banesh Hoffmann: "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."
As to the important consequences of the invariance of c that Joe Wolfe's students have to understand, here are some of them:
math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html
"These are the props. You own a barn, 40m long, with automatic doors at either end, that can be opened and closed simultaneously by a switch. You also have a pole, 80m long, which of course won't fit in the barn. (...) If it does not explode under the strain and it is sufficiently elastic it will come to rest and start to spring back to its natural shape but since it is too big for the barn the other end is now going to crash into the back door and the rod will be trapped IN A COMPRESSED STATE inside the barn."
www.quebecscience.qc.ca/Revolutions
Stéphane Durand: "Ainsi, une fusée de 100 m passant à toute vitesse dans un tunnel de 60 m pourrait être entièrement contenue dans ce tunnel pendant une fraction de seconde, durant laquelle il serait possible de fermer des portes aux deux bouts! La fusée est donc réellement plus courte. Pourtant, il n'y a PAS DE COMPRESSION matérielle ou physique de l'engin."
hyperphysics.phy-astr.gsu.edu/Hbase/Relativ/bugrivet.html
"The bug-rivet paradox is a variation on the twin paradox and is similar to the pole-barn paradox.....The end of the rivet hits the bottom of the hole before the head of the rivet hits the wall. So it looks like the bug is squashed.....All this is nonsense from the bug's point of view. The rivet head hits the wall when the rivet end is just 0.35 cm down in the hole! The rivet doesn't get close to the bug....The paradox is not resolved."
math.ucr.edu/~jdp/Relativity/Bug_Rivet.html
John de Pillis Professor of Mathematics: "In fact, special relativity requires that after collision, the rivet shank length increases beyond its at-rest length d."
Pentcho Valev
pvalev@yahoo.com
Professor Joe Wolfe: "At this stage, many of my students say things like "The invariance of the speed of light among observers is impossible" or "I can't understand it". Well, it's not impossible. It's even more than possible, it is true. This is something that has been extensively measured, and many refinements to the Michelson and Morely experiment, and complementary experiments have confirmed this invariance to very great precision. As to understanding it, there isn't really much to understand. However surprising and weird it may be, it is the case. It's the law in our universe. The fact of the invariance of c doesn't take much understanding: what requires understanding are its consequences, and how it can be integrated into what we already know."
Needless to say, the Michelson-Morley experiment has not confirmed the invariance of the speed of light:
www.pitt.edu/~jdnorton/papers/companion.doc
John Norton: "These efforts were long misled by an exaggeration of the importance of one experiment, the Michelson-Morley experiment, even though Einstein later had trouble recalling if he even knew of the experiment prior to his 1905 paper. This one experiment, in isolation, has little force. Its null result happened to be fully compatible with Newton's own emission theory of light. Located in the context of late 19th century electrodynamics when ether-based, wave theories of light predominated, however, it presented a serious problem that exercised the greatest theoretician of the day."
philsci-archive.pitt.edu/1743/2/Norton.pdf
John Norton: "In addition to his work as editor of the Einstein papers in finding source material, Stachel assembled the many small clues that reveal Einstein's serious consideration of an emission theory of light; and he gave us the crucial insight that Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity. Even today, this point needs emphasis. The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE."
www.amazon.com/Relativity-Its-Roots-Bane...ffmann/dp/0486406768
"Relativity and Its Roots" By Banesh Hoffmann: "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."
As to the important consequences of the invariance of c that Joe Wolfe's students have to understand, here are some of them:
math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html
"These are the props. You own a barn, 40m long, with automatic doors at either end, that can be opened and closed simultaneously by a switch. You also have a pole, 80m long, which of course won't fit in the barn. (...) If it does not explode under the strain and it is sufficiently elastic it will come to rest and start to spring back to its natural shape but since it is too big for the barn the other end is now going to crash into the back door and the rod will be trapped IN A COMPRESSED STATE inside the barn."
www.quebecscience.qc.ca/Revolutions
Stéphane Durand: "Ainsi, une fusée de 100 m passant à toute vitesse dans un tunnel de 60 m pourrait être entièrement contenue dans ce tunnel pendant une fraction de seconde, durant laquelle il serait possible de fermer des portes aux deux bouts! La fusée est donc réellement plus courte. Pourtant, il n'y a PAS DE COMPRESSION matérielle ou physique de l'engin."
hyperphysics.phy-astr.gsu.edu/Hbase/Relativ/bugrivet.html
"The bug-rivet paradox is a variation on the twin paradox and is similar to the pole-barn paradox.....The end of the rivet hits the bottom of the hole before the head of the rivet hits the wall. So it looks like the bug is squashed.....All this is nonsense from the bug's point of view. The rivet head hits the wall when the rivet end is just 0.35 cm down in the hole! The rivet doesn't get close to the bug....The paradox is not resolved."
math.ucr.edu/~jdp/Relativity/Bug_Rivet.html
John de Pillis Professor of Mathematics: "In fact, special relativity requires that after collision, the rivet shank length increases beyond its at-rest length d."
Pentcho Valev
pvalev@yahoo.com
4 days ago
Pentcho replied to the topic Re: Einsteiniana: Two Crucial Questions in the forums.
CRUCIAL QUESTION 3: Both Newton's emission theory of light and Maxwell's ether theory, unlike special relativity, predict that the frequency and the speed of light, as measured by the observer, vary with the speed of the observer. On the other hand, when the observer starts moving towards the light source with speed v (c>>v), the frequency shift seems to ALWAYS obey the equation f'=f(1+v/c). Does this support Newton's emission theory of light or Maxwell's ether theory (or both)?
ANSWER: If the frequency shift ALWAYS obeys the equation f'=f(1+v/c), then only Newton's emission theory of light gets support while Maxwell's ether theory is refuted. The latter predicts that the frequency shifts in accordance with the equation f'=f(1+v/(c±V)), where V is the speed of the ether wind along the line connecting source and observer, relative to the source.
Pentcho Valev
pvalev@yahoo.com
ANSWER: If the frequency shift ALWAYS obeys the equation f'=f(1+v/c), then only Newton's emission theory of light gets support while Maxwell's ether theory is refuted. The latter predicts that the frequency shifts in accordance with the equation f'=f(1+v/(c±V)), where V is the speed of the ether wind along the line connecting source and observer, relative to the source.
Pentcho Valev
pvalev@yahoo.com
4 days ago
socrat created a new topic Does somebody know what Vacuum is ? in the forums.
Does somebody know what Vacuum is ?
1.
Book : ‘Dreams of a final theory’ by Steven Weinberg. Page 138.
‘ It is true . . . there is such a thing as absolute zero; we cannot
reach temperatures below absolute zero not because we are not
sufficiently clever but because temperatures below absolute zero
simple have no meaning.’
/ Steven Weinberg. The Nobel Prize in Physics 1979 /
2.
‘If we were looking for something that we could conceive
of as God within the universe of the new physics,
this ground state, coherent quantum vacuum might be
a good place to start.’
/ Book ‘The quantum self ’ page 208 by Danah Zohar. /
3.
And Paul Dirac wrote:
‘ The problem of the exact description of vacuum, in my opinion,
is the basic problem now before physics. Really, if you can’t correctly
describe the vacuum, how it is possible to expect a correct description
of something more complex? ‘
==.
Does somebody know what Vacuum is ?
==.
Socratus
1.
Book : ‘Dreams of a final theory’ by Steven Weinberg. Page 138.
‘ It is true . . . there is such a thing as absolute zero; we cannot
reach temperatures below absolute zero not because we are not
sufficiently clever but because temperatures below absolute zero
simple have no meaning.’
/ Steven Weinberg. The Nobel Prize in Physics 1979 /
2.
‘If we were looking for something that we could conceive
of as God within the universe of the new physics,
this ground state, coherent quantum vacuum might be
a good place to start.’
/ Book ‘The quantum self ’ page 208 by Danah Zohar. /
3.
And Paul Dirac wrote:
‘ The problem of the exact description of vacuum, in my opinion,
is the basic problem now before physics. Really, if you can’t correctly
describe the vacuum, how it is possible to expect a correct description
of something more complex? ‘
==.
Does somebody know what Vacuum is ?
==.
Socratus
4 days ago
Pentcho created a new topic Einsteiniana: Two Crucial Questions in the forums.
QUESTION 1: The frequency of light (as measured by the observer) varies with the speed of the observer. Does this mean that the speed of light (as measured by the observer) also varies with the speed of the observer, in violation of Einstein's special relativity?
Clues:
a-levelphysicstutor.com/wav-doppler.php
"vO is the velocity of an observer moving towards the source. This velocity is independent of the motion of the source. Hence, the velocity of waves relative to the observer is c + vO. (...) The motion of an observer does not alter the wavelength. The increase in frequency is a result of the observer encountering more wavelengths in a given time."
www.expo-db.be/ExposPrecedentes/Expo/Ond.../Effet%20Doppler.pdf
"La variation de la fréquence observée lorsqu'il y a mouvement relatif entre la source et l'observateur est appelée effet Doppler. (...) 6. Source immobile - Observateur en mouvement: La distance entre les crêtes, la longueur d'onde lambda ne change pas. Mais la vitesse des crêtes par rapport à l'observateur change !"
www.usna.edu/Users/physics/mungan/Scholarship/DopplerEffect.pdf
Carl Mungan: "Consider the case where the observer moves toward the source. In this case, the observer is rushing head-long into the wavefronts... (...) In fact, the wave speed is simply increased by the observer speed, as we can see by jumping into the observer's frame of reference."
www.hep.man.ac.uk/u/roger/PHYS10302/lecture18.pdf
Roger Barlow, Professor of Particle Physics: "Moving Observer. Now suppose the source is fixed but the observer is moving towards the source, with speed v. In time t, ct/(lambda) waves pass a fixed point. A moving point adds another vt/(lambda). So f'=(c+v)/(lambda)."
www.cmmp.ucl.ac.uk/~ahh/teaching/1B24n/lect19.pdf
Tony Harker, University College London: "If the observer moves with a speed Vo away from the source (...), then in a time t the number of waves which reach the observer are those in a distance (c-Vo)t, so the number of waves observed is (c-Vo)t/lambda, giving an observed frequency f'=f((c-Vo)/c) when the observer is moving away from the source at a speed Vo."
www.einstein-online.info/spotlights/doppler
Albert Einstein Institute: "As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses [that is, the speed of light as measured by the receiver is (4/3)c]."
QUESTION 2: The frequency of light falling in a gravitational field increases in accordance with the equation f'=f(1+gh/c^2), as predicted by Newton's emission theory of light. Does this mean that the speed of light also increases, in accordance with another prediction of the emission theory, c'=c(1+gh/c^2)?
Clues:
online.physics.uiuc.edu/courses/phys419/.../Lecture13/L13r.html
University of Illinois at Urbana-Champaign: "Consider a falling object. ITS SPEED INCREASES AS IT IS FALLING. Hence, if we were to associate a frequency with that object the frequency should increase accordingly as it falls to earth. Because of the equivalence between gravitational and inertial mass, WE SHOULD OBSERVE THE SAME EFFECT FOR LIGHT. So lets shine a light beam from the top of a very tall building. If we can measure the frequency shift as the light beam descends the building, we should be able to discern how gravity affects a falling light beam. This was done by Pound and Rebka in 1960. They shone a light from the top of the Jefferson tower at Harvard and measured the frequency shift. The frequency shift was tiny but in agreement with the theoretical prediction."
www.einstein-online.info/spotlights/redshift_white_dwarfs
Albert Einstein Institute: "One of the three classical tests for general relativity is the gravitational redshift of light or other forms of electromagnetic radiation. However, in contrast to the other two tests - the gravitational deflection of light and the relativistic perihelion shift -, you do not need general relativity to derive the correct prediction for the gravitational redshift. A combination of Newtonian gravity, a particle theory of light, and the weak equivalence principle (gravitating mass equals inertial mass) suffices."
arxiv.org/ftp/gr-qc/papers/0403/0403082.pdf
The Gravitational Red-Shift, R.F.Evans and J.Dunning-Davies, Department of Physics, University of Hull: "Attention is drawn to the fact that the well-known expression for the red-shift of spectral lines due to a gravitational field may be derived with no recourse to the theory of general relativity. This raises grave doubts over the inclusion of the measurement of this gravitational red-shift in the list of crucial tests of the theory of general relativity. (...) In truth, it would seem that the result for the red-shift of spectral lines due to the action of a gravitational field has nothing specifically to do with the theory of general relativity. It is a result which draws on more modern results due to such as Planck and Poincaré, but, apart from those, is deduced from notions of Newtonian mechanics alone."
"Relativity 3 - gravity and light"
www.damtp.cam.ac.uk/user/hsr1000/lecturenotes12_02.pdf
Harvey Reall, University of Cambridge: "...light falls in the gravitational field in exactly the same way as a massive test particle."
sethi.lamar.edu/bahrim-cristian/Courses/...-gravit-lens_PPT.pdf
Dr. Cristian Bahrim: "If we accept the principle of equivalence, we must also accept that light falls in a gravitational field with the same acceleration as material bodies."
membres.multimania.fr/juvastro/calculs/einstein.pdf
"Le principe d'équivalence, un des fondements de base de la relativité générale prédit que dans un champ gravitationnel, la lumière tombe comme tout corps matériel selon l'acceleration de la pesanteur."
www.wfu.edu/~brehme/space.htm
Robert W. Brehme: "Light falls in a gravitational field just as do material objects."
Pentcho Valev
pvalev@yahoo.com
Clues:
a-levelphysicstutor.com/wav-doppler.php
"vO is the velocity of an observer moving towards the source. This velocity is independent of the motion of the source. Hence, the velocity of waves relative to the observer is c + vO. (...) The motion of an observer does not alter the wavelength. The increase in frequency is a result of the observer encountering more wavelengths in a given time."
www.expo-db.be/ExposPrecedentes/Expo/Ond.../Effet%20Doppler.pdf
"La variation de la fréquence observée lorsqu'il y a mouvement relatif entre la source et l'observateur est appelée effet Doppler. (...) 6. Source immobile - Observateur en mouvement: La distance entre les crêtes, la longueur d'onde lambda ne change pas. Mais la vitesse des crêtes par rapport à l'observateur change !"
www.usna.edu/Users/physics/mungan/Scholarship/DopplerEffect.pdf
Carl Mungan: "Consider the case where the observer moves toward the source. In this case, the observer is rushing head-long into the wavefronts... (...) In fact, the wave speed is simply increased by the observer speed, as we can see by jumping into the observer's frame of reference."
www.hep.man.ac.uk/u/roger/PHYS10302/lecture18.pdf
Roger Barlow, Professor of Particle Physics: "Moving Observer. Now suppose the source is fixed but the observer is moving towards the source, with speed v. In time t, ct/(lambda) waves pass a fixed point. A moving point adds another vt/(lambda). So f'=(c+v)/(lambda)."
www.cmmp.ucl.ac.uk/~ahh/teaching/1B24n/lect19.pdf
Tony Harker, University College London: "If the observer moves with a speed Vo away from the source (...), then in a time t the number of waves which reach the observer are those in a distance (c-Vo)t, so the number of waves observed is (c-Vo)t/lambda, giving an observed frequency f'=f((c-Vo)/c) when the observer is moving away from the source at a speed Vo."
www.einstein-online.info/spotlights/doppler
Albert Einstein Institute: "As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses [that is, the speed of light as measured by the receiver is (4/3)c]."
QUESTION 2: The frequency of light falling in a gravitational field increases in accordance with the equation f'=f(1+gh/c^2), as predicted by Newton's emission theory of light. Does this mean that the speed of light also increases, in accordance with another prediction of the emission theory, c'=c(1+gh/c^2)?
Clues:
online.physics.uiuc.edu/courses/phys419/.../Lecture13/L13r.html
University of Illinois at Urbana-Champaign: "Consider a falling object. ITS SPEED INCREASES AS IT IS FALLING. Hence, if we were to associate a frequency with that object the frequency should increase accordingly as it falls to earth. Because of the equivalence between gravitational and inertial mass, WE SHOULD OBSERVE THE SAME EFFECT FOR LIGHT. So lets shine a light beam from the top of a very tall building. If we can measure the frequency shift as the light beam descends the building, we should be able to discern how gravity affects a falling light beam. This was done by Pound and Rebka in 1960. They shone a light from the top of the Jefferson tower at Harvard and measured the frequency shift. The frequency shift was tiny but in agreement with the theoretical prediction."
www.einstein-online.info/spotlights/redshift_white_dwarfs
Albert Einstein Institute: "One of the three classical tests for general relativity is the gravitational redshift of light or other forms of electromagnetic radiation. However, in contrast to the other two tests - the gravitational deflection of light and the relativistic perihelion shift -, you do not need general relativity to derive the correct prediction for the gravitational redshift. A combination of Newtonian gravity, a particle theory of light, and the weak equivalence principle (gravitating mass equals inertial mass) suffices."
arxiv.org/ftp/gr-qc/papers/0403/0403082.pdf
The Gravitational Red-Shift, R.F.Evans and J.Dunning-Davies, Department of Physics, University of Hull: "Attention is drawn to the fact that the well-known expression for the red-shift of spectral lines due to a gravitational field may be derived with no recourse to the theory of general relativity. This raises grave doubts over the inclusion of the measurement of this gravitational red-shift in the list of crucial tests of the theory of general relativity. (...) In truth, it would seem that the result for the red-shift of spectral lines due to the action of a gravitational field has nothing specifically to do with the theory of general relativity. It is a result which draws on more modern results due to such as Planck and Poincaré, but, apart from those, is deduced from notions of Newtonian mechanics alone."
"Relativity 3 - gravity and light"
www.damtp.cam.ac.uk/user/hsr1000/lecturenotes12_02.pdf
Harvey Reall, University of Cambridge: "...light falls in the gravitational field in exactly the same way as a massive test particle."
sethi.lamar.edu/bahrim-cristian/Courses/...-gravit-lens_PPT.pdf
Dr. Cristian Bahrim: "If we accept the principle of equivalence, we must also accept that light falls in a gravitational field with the same acceleration as material bodies."
membres.multimania.fr/juvastro/calculs/einstein.pdf
"Le principe d'équivalence, un des fondements de base de la relativité générale prédit que dans un champ gravitationnel, la lumière tombe comme tout corps matériel selon l'acceleration de la pesanteur."
www.wfu.edu/~brehme/space.htm
Robert W. Brehme: "Light falls in a gravitational field just as do material objects."
Pentcho Valev
pvalev@yahoo.com
4 days ago
Pentcho replied to the topic Re: Einsteiniana: The Fatal Argument in the forums.
PREMISE 1: In a gravitational field, the speed of light does not vary at all:
www.amazon.com/Why-Does-mc2-Should-Care/dp/0306817586
Why Does E=mc2?: (And Why Should We Care?), Brian Cox, Jeff Forshaw, p. 236: "If the light falls in strict accord with the principle of equivalence, then, as it falls, its energy should increase by exactly the same fraction that it increases for any other thing we could imagine dropping. We need to know what happens to the light as it gains energy. In other words, what can Pound and Rebka expect to see at the bottom of their laboratory when the dropped light arrives? There is only one way for the light to increase its energy. We know that it cannot speed up, because it is already traveling at the universal speed limit, but it can increase its frequency."
www.amazon.com/Brief-History-Time-Stephen-Hawking/dp/0553380168
Stephen Hawking, A Brief History of Time, Chapter 6: "A cannonball fired upward from the earth will be slowed down by gravity and will eventually stop and fall back; a photon, however, must continue upward at a constant speed..."
CONCLUSION 1: In gravitation-free space, the speed of light (as measured by the receiver) does not vary with the speed of the receiver.
VALIDITY OF ARGUMENT 1: The emitter (E) and the receiver (R) are at rest: E at the earth surface, R at a distance h above E. In accordance with PREMISE 1, the receiver measures the speed of light to be unchanged, c'=c. This scenario is equivalent to one in which E and R are fixed in an elevator accelerating, in gravitation-free space, with constant acceleration g in the direction E->R. So when the light signal reaches R, R has acquired speed v=gh/c. Nevertheless, the receiver in the elevator measures the speed of light to be c'=c.
PREMISE 2: In a gravitational field, the speed of light varies two times faster than the speed of cannonballs:
arxiv.org/pdf/gr-qc/9909014v1.pdf
Steve Carlip: "It is well known that the deflection of light is twice that predicted by Newtonian theory; in this sense, at least, light falls with twice the acceleration of ordinary "slow" matter."
www.speed-light.info/speed_of_light_variable.htm
"You can find a more sophisticated derivation later by Einstein (1955) from the full theory of general relativity in the weak field approximation: (...) Namely the 1955 approximation shows a variation in km/sec twice as much as first predicted in 1911."
CONCLUSION 2: In gravitation-free space, the speed of light (as measured by the receiver) varies with the speed of the receiver.
VALIDITY OF ARGUMENT 2: The emitter (E) and the receiver (R) are at rest: E at the earth surface, R at a distance h above E. In accordance with PREMISE 2, the receiver measures the speed of light to be c'=c(1-2gh/c^2). This scenario is equivalent to one in which E and R are fixed in an elevator accelerating, in gravitation-free space, with constant acceleration g in the direction E->R. So when the light signal reaches R, R has acquired speed v=gh/c. Accordingly, the receiver in the elevator measures the speed of light to be c'=c(1-2gh/c^2)=c-2v.
Clearly only PREMISE 1 is compatible with special relativity. Both Einstein's general relativity and Newton's emission theory of light are incompatible with special relativity. Joao Magueijo and Lee Smolin were right:
www.amazon.com/Faster-Than-Speed-Light-S...lation/dp/0738205257
Joao Magueijo, Faster Than the Speed of Light: The Story of a Scientific Speculation, p. 250: "Lee [Smolin] and I discussed these paradoxes at great length for many months, starting in January 2001. We would meet in cafés in South Kensington or Holland Park to mull over the problem. THE ROOT OF ALL THE EVIL WAS CLEARLY SPECIAL RELATIVITY. All these paradoxes resulted from well known effects such as length contraction, time dilation, or E=mc^2, all basic predictions of special relativity."
Pentcho Valev
pvalev@yahoo.com
www.amazon.com/Why-Does-mc2-Should-Care/dp/0306817586
Why Does E=mc2?: (And Why Should We Care?), Brian Cox, Jeff Forshaw, p. 236: "If the light falls in strict accord with the principle of equivalence, then, as it falls, its energy should increase by exactly the same fraction that it increases for any other thing we could imagine dropping. We need to know what happens to the light as it gains energy. In other words, what can Pound and Rebka expect to see at the bottom of their laboratory when the dropped light arrives? There is only one way for the light to increase its energy. We know that it cannot speed up, because it is already traveling at the universal speed limit, but it can increase its frequency."
www.amazon.com/Brief-History-Time-Stephen-Hawking/dp/0553380168
Stephen Hawking, A Brief History of Time, Chapter 6: "A cannonball fired upward from the earth will be slowed down by gravity and will eventually stop and fall back; a photon, however, must continue upward at a constant speed..."
CONCLUSION 1: In gravitation-free space, the speed of light (as measured by the receiver) does not vary with the speed of the receiver.
VALIDITY OF ARGUMENT 1: The emitter (E) and the receiver (R) are at rest: E at the earth surface, R at a distance h above E. In accordance with PREMISE 1, the receiver measures the speed of light to be unchanged, c'=c. This scenario is equivalent to one in which E and R are fixed in an elevator accelerating, in gravitation-free space, with constant acceleration g in the direction E->R. So when the light signal reaches R, R has acquired speed v=gh/c. Nevertheless, the receiver in the elevator measures the speed of light to be c'=c.
PREMISE 2: In a gravitational field, the speed of light varies two times faster than the speed of cannonballs:
arxiv.org/pdf/gr-qc/9909014v1.pdf
Steve Carlip: "It is well known that the deflection of light is twice that predicted by Newtonian theory; in this sense, at least, light falls with twice the acceleration of ordinary "slow" matter."
www.speed-light.info/speed_of_light_variable.htm
"You can find a more sophisticated derivation later by Einstein (1955) from the full theory of general relativity in the weak field approximation: (...) Namely the 1955 approximation shows a variation in km/sec twice as much as first predicted in 1911."
CONCLUSION 2: In gravitation-free space, the speed of light (as measured by the receiver) varies with the speed of the receiver.
VALIDITY OF ARGUMENT 2: The emitter (E) and the receiver (R) are at rest: E at the earth surface, R at a distance h above E. In accordance with PREMISE 2, the receiver measures the speed of light to be c'=c(1-2gh/c^2). This scenario is equivalent to one in which E and R are fixed in an elevator accelerating, in gravitation-free space, with constant acceleration g in the direction E->R. So when the light signal reaches R, R has acquired speed v=gh/c. Accordingly, the receiver in the elevator measures the speed of light to be c'=c(1-2gh/c^2)=c-2v.
Clearly only PREMISE 1 is compatible with special relativity. Both Einstein's general relativity and Newton's emission theory of light are incompatible with special relativity. Joao Magueijo and Lee Smolin were right:
www.amazon.com/Faster-Than-Speed-Light-S...lation/dp/0738205257
Joao Magueijo, Faster Than the Speed of Light: The Story of a Scientific Speculation, p. 250: "Lee [Smolin] and I discussed these paradoxes at great length for many months, starting in January 2001. We would meet in cafés in South Kensington or Holland Park to mull over the problem. THE ROOT OF ALL THE EVIL WAS CLEARLY SPECIAL RELATIVITY. All these paradoxes resulted from well known effects such as length contraction, time dilation, or E=mc^2, all basic predictions of special relativity."
Pentcho Valev
pvalev@yahoo.com
5 days ago
Pentcho replied to the topic Re: Einsteiniana: The Fatal Argument in the forums.
PREMISE 1: In a gravitational field, the speed of light varies exactly as the speed of cannonballs does.
PREMISE 2: The variation of the frequency with the gravitational potential is due to the variation of the speed of light with the gravitational potential:
online.physics.uiuc.edu/courses/phys419/.../Lecture13/L13r.html
University of Illinois at Urbana-Champaign: "Consider a falling object. ITS SPEED INCREASES AS IT IS FALLING. Hence, if we were to associate a frequency with that object the frequency should increase accordingly as it falls to earth. Because of the equivalence between gravitational and inertial mass, WE SHOULD OBSERVE THE SAME EFFECT FOR LIGHT. So lets shine a light beam from the top of a very tall building. If we can measure the frequency shift as the light beam descends the building, we should be able to discern how gravity affects a falling light beam. This was done by Pound and Rebka in 1960. They shone a light from the top of the Jefferson tower at Harvard and measured the frequency shift. The frequency shift was tiny but in agreement with the theoretical prediction."
arxiv.org/pdf/1109.6571v1.pdf
Nature 477, 567-569 (29 September 2011), Gravitational redshift of galaxies in clusters as predicted by general relativity, Radoslaw Wojtak, Steen H. Hansen, Jens Hjorth: "According to the theory of general relativity, light emitted from galaxies moving in the gravitational potential well of galaxy clusters is expected to be redshifted proportionally to the difference in gravitational potential phi between the clusters and an observer, i.e., z_gr = (delta phi)/c^2, where c is the velocity of light in vacuum."
CONCLUSION: Redshifted light coming to earth has a speed lower than c. Part of the decrease is caused by the gravitational field of the emitter.
Pentcho Valev
pvalev@yahoo.com
PREMISE 2: The variation of the frequency with the gravitational potential is due to the variation of the speed of light with the gravitational potential:
online.physics.uiuc.edu/courses/phys419/.../Lecture13/L13r.html
University of Illinois at Urbana-Champaign: "Consider a falling object. ITS SPEED INCREASES AS IT IS FALLING. Hence, if we were to associate a frequency with that object the frequency should increase accordingly as it falls to earth. Because of the equivalence between gravitational and inertial mass, WE SHOULD OBSERVE THE SAME EFFECT FOR LIGHT. So lets shine a light beam from the top of a very tall building. If we can measure the frequency shift as the light beam descends the building, we should be able to discern how gravity affects a falling light beam. This was done by Pound and Rebka in 1960. They shone a light from the top of the Jefferson tower at Harvard and measured the frequency shift. The frequency shift was tiny but in agreement with the theoretical prediction."
arxiv.org/pdf/1109.6571v1.pdf
Nature 477, 567-569 (29 September 2011), Gravitational redshift of galaxies in clusters as predicted by general relativity, Radoslaw Wojtak, Steen H. Hansen, Jens Hjorth: "According to the theory of general relativity, light emitted from galaxies moving in the gravitational potential well of galaxy clusters is expected to be redshifted proportionally to the difference in gravitational potential phi between the clusters and an observer, i.e., z_gr = (delta phi)/c^2, where c is the velocity of light in vacuum."
CONCLUSION: Redshifted light coming to earth has a speed lower than c. Part of the decrease is caused by the gravitational field of the emitter.
Pentcho Valev
pvalev@yahoo.com
6 days ago
Pentcho replied to the topic Re: Einsteiniana: The Fatal Argument in the forums.
The speed of cannonballs shot downwards with initial speed V (relative to the shooter) varies with the gravitational potential (gh) in accordance with the equation V'=V(1+gh/V^2) (it is assumed that V>>(V'-V) and air friction is ignored). If the cannonball is shot from top to bottom in an elevator of height h accelerating, in gravitation-free space, with constant acceleration g, then the bottom has acquired speed v=gh/V when it meets the cannonball. Accordingly, the speed of the cannonball as measured at the bottom is V'=V(1+gh/V^2)=V+v.
If, in a gravitational field, the speed of photons varies exactly as the speed of cannonballs does, then the speed of a light signal emitted downwards with initial speed c (relative to the emitter) varies with the gravitational potential (gh) in accordance with the equation c'=c(1+gh/c^2). If the signal is emitted from top to bottom in an elevator of height h accelerating, in gravitation-free space, with constant acceleration g, then the bottom has acquired speed v=gh/c when it meets the signal. Accordingly, the speed of the signal as measured at the bottom is c'=c(1+gh/c^2)=c+v.
The equation c'=c+v is fatal for Einstein's relativity. In the context of the above argument, its truth entirely depends on the PREMISE:
"Light falls in a gravitational field with the same acceleration as cannonballs"
If the PREMISE is true, the equation c'=c+v is true. If not, not.
Pentcho Valev
pvalev@yahoo.com
If, in a gravitational field, the speed of photons varies exactly as the speed of cannonballs does, then the speed of a light signal emitted downwards with initial speed c (relative to the emitter) varies with the gravitational potential (gh) in accordance with the equation c'=c(1+gh/c^2). If the signal is emitted from top to bottom in an elevator of height h accelerating, in gravitation-free space, with constant acceleration g, then the bottom has acquired speed v=gh/c when it meets the signal. Accordingly, the speed of the signal as measured at the bottom is c'=c(1+gh/c^2)=c+v.
The equation c'=c+v is fatal for Einstein's relativity. In the context of the above argument, its truth entirely depends on the PREMISE:
"Light falls in a gravitational field with the same acceleration as cannonballs"
If the PREMISE is true, the equation c'=c+v is true. If not, not.
Pentcho Valev
pvalev@yahoo.com
7 days ago