In modern physics, light and all electromagnetic wave are emitted at the same speed in the rest frame of the wave source. The speed is commonly knows as "speed of light". The speed remains invariant until reflection. The wavelength is invariant upon reflection. However, the frequency depends on the relative motion. As a result, the speed changes if a different frequency is detected.

The evidence emerges in the FG5 gravimeter. The time data of this scientific instrument indicates a faster light reflected by a falling mirror.

Another evidence of detection in daily life for faster or slower light is the motion detector. It emits signal toward a moving object and records a higher or lower frequency when the signal returns. The wavelength is invariant upon reflection. As the signal speeds up, its frequency increases accordingly.

The common mistake in modern physics is to assume the wavelength is altered by reflection. This popular assumption has never been verified nor proved. It originates from the assumption of relativity. Unfounded but taken as granted without proof.

The experimental evidences that speed of light can change have been ignored for over a century until the theoretical proofs become available on this website in 2017.

The simplest proof is from the standing wave in a microwave cavity[60]. The standing wave consists of two waves with identical wavelength. The two wavelengths are identical to all moving observers. However, the two frequencies become different to all moving observers. Hence, the speeds of two waves also become different.

2020-6-1

The standing wave exists in a microwave resonator if the length of the resonator cavity is equal to multiple half-wavelengths of microwave. The stationary interference of standing wave will travel in another inertial reference frame. The vibrating pattern of the standing wave is conserved.

The existence of nodes in all reference frames requires the wavelength of the microwave to be conserved in all inertial reference frames. The angular frequency of microwave is different in every reference frame. Hence, the apparent velocity of the microwave depends on the choice of reference frame while the elapsed time remains invariant in all reference frames.

The FG5 gravimeter records the time when the interference pattern changes color. The data proves that light reflected by a falling mirror becomes faster in time.

The radar speed gun for traffic police records the frequency of the radio wave reflected by a moving vehicle. The speed of radio wave is proportional to the frequency while the wavelength stays intact. Higher frequency corresponds to faster radio wave.

The redshift and blueshift in astronomy are the result of the relative motion between the earth and the remote star. Blueshift is observed on an approaching star. The frequency increases while the wavelength stays intact. Higher frequency corresponds to faster light.

Faster radio signal has been detected by the traffic police on a daily basis. The radar speed gun emits radio signal toward the vehicle. The frequency and the speed of the reflected radio increases as the vehicle moves toward the radar speed gun.

In modern physics, light and all electromagnetic wave are emitted at the same speed which is commonly knows as "speed of light". The speed remains invariant until reflection. The wavelength is invariant upon reflection. However, the frequency as well as the speed depend on the relative motion. As a result, the speed changes if a different frequency is detected.

The evidence emerges in the FG5 gravimeter clearly. The time data of this scientific instrument indicates a faster light reflected by a falling mirror.

Another example in daily life to detect a faster or slower light is the motion detector. It emits signal toward any moving object and records a higher or lower frequency when the signal returns. As the signal speeds up, its frequency increases accordingly.

The common mistake in modern physics is to assume the wavelength is different upon reflection. This popular assumption has never been verified nor proved. It originates from the assumption of relativity. Unfounded but takend as granted without proof.

The experimental evidences that speed of light can change have been ignored for over a century until the theoretical proofs become available in 2017.

The simplest proof is from the standing wave in a microwave cavity. The standing wave consists of two waves with identical wavelength. The two wavelengths are identical to all moving observers. However, the two frequencies become different to all moving observers. Hence, the speeds of two waves also become different.

2019-01-12

41. The conservation of the interference pattern from double slit interference proves that the wavelength is conserved in all inertial reference frames.

However, there is a popular belief in modern astronomy that the wavelength can be changed by the choice of reference frame. This erroneous belief results in the problematic prediction of the radial speed of galaxy.

The reflection symmetry shows that the elapsed time is conserved in all inertial reference frames. From both conservation properties, the velocity of the light is proved to be different in a different reference frame. This different velocity was confirmed by lunar laser ranging test at NASA in 2009.

The relative motion between the light source and the light detector bears great similarity to the magnetic force on a moving charge. The motion changes the interference pattern but not the wavelength in the rest frame of the star. This is known as the blueshift or the redshift in astronomy. The speed of light in the rest frame of the grism determines how the spectrum is shifted. Wide Field Camera 3 in Hubble Space Telescope provides an excellent example on how the speed of light can change the spectrum.

57. A standing wave can be formed in a microwave resonator if the length of the resonator cavity is equal to multiple half wavelengths. The stationary standing wave becomes a moving standing wave in another inertial reference frame.

The covariance property of the moving standing wave verifies that the frequencies of two microwaves forming the standing wave become different in the new reference frame while the wavelengths remain identical.

Hence, the apparent speed of the microwave appears to be different in a different inertial reference frame.

58. The velocity of a wave depends on the choice of reference frame. The relative motion between the rest frames of the wave source, the observer, and the wave determines the apparent wavelength and apparent period in each rest frame.

The apparent period is different from the original period unless the wave source and the observer occupy the same rest frame. The apparent wavelength is identical to the original wavelength unless the relative motion between the wave source and the wave is non-inertial. The observed wavelength is identical to all observers. A time varying wavelength is an indication that a remote star is in non-inertial motion during star birth.

The inertial force corresponding to the non-inertial relative motion between the rest frames can not be identified as any fundamental force. A neutral object in the non-inertial motion is not attracted by electric force. The massless microwave in the non-inertial reference frame is not attracted by gravitational force.

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49. The absolute gravimeter measures the gravitational constant by dropping a corner cube retro-reflector in a vacuum. The light reflected by the corner cube interferes with another light from the same emission.

The interference pattern can not be explained by the theory if the speed of light remains constant upon reflection.Two research teams were obliged to propose new definition of acceleration to match their test data.Neither team understands that the speed of light actually changes upon reflection by a moving mirror.

The definition of acceleration should remain intact. The speed of reflected light should increase to match the observed fringe pattern from the gravimeter.

29. The application of reflection symmetry to two inertial reference frames shows that the elapsed time is conserved in all inertial reference frames. The conservation of the elapsed time indicates that the reflection of light between a pair of stationary mirrors should take the same elapsed time in all inertial reference frames. In one reference frame, both mirrors are stationary. In other reference frames, both mirrors are moving. The distance traveled by the light between the moving mirrors depends on the direction. The conservation law shows that the light travels at a different speed upon reflection by a moving mirror.

27. The reflection symmetry is a physical property for inertial reference frames. It shows that the elapsed time in one inertial reference frame is identical to the elapsed time in another inertial reference frame. The same symmetry also leads to the conservation of the wavelength across inertial reference frames. The velocity of a wave is proportional to its frequency. Doppler effect shows that both the velocity and the frequency depend on the reference frame. The higher the detected frequency is, the faster the wave travels toward the detector. One example is the radar gun used by the traffic police. The reflected radio wave travels faster than the emitted radio wave. This results in frequency difference between two waves. This difference is used to calculate the velocity of a vehicle.

25. The radio wave changes direction upon reflection. It also changes frequency if it is reflected by a moving surface. In the standing wave formed by the incident wave and the reflected wave, the formation of the nodes requires both waves to have the same wavelength. The nodes exist in all reference frames. This requires both the incident wave and the reflected wave to have the same wavelength in all reference frames. However, these two waves have different frequencies due to Doppler effect Therefore, these two waves travel at different speeds. Doppler radar is a good example. With two moving surfaces to reflect the radio wave between them, the radio wave can be accelerated if the distance between two reflective surfaces decreases with time.

Michelson-Morley experiment can be found in the following link.

https://en.wikisource.org/wiki/On_the_Relative_Motion_of_the_Earth_and_the_Luminiferous_Ether

1) All instruments on the stone platform are stationary relative to the rest frame of the stone platform. As a result, physics remains invariant in any orientation of this system. The rotation symmetry ensures that the speed of light in this isolated system remains constant in any orientation.

In order to detect any variation in the speed of light, the rest frame of the detector needs to be different from the rest frame of the emitter.

2) The error in the experiment is associated with the speed of the reflected light. Both Michelson and Morley assumed that the speed of light is not altered upon reflection by a moving mirror. This is true only in the rest frame of the laboratory but not in a different reference frame The error rendered the calculation of distance incorrect and eventually led to the speculation of length contraction.

As a result, Lorentz transformation was proposed.

31. Michelson and Morley carried out an experiment in 1887 to determine if the theory of ether is correct. The experiment shows that the speed of light is constant in all directions. However, an error in this experiment was introduced by the calculation of the elapsed time for light to travel between two moving mirrors in the rest frame of ether. Both Michelson and Morley assumed that the speed of light is not altered upon reflection by a moving mirror. This critical error produced a small variation in the distance traveled by the light between mirrors in the rest frame of ether. As a result, Lorentz transformation was proposed to explain the concept of length contraction.

20. Based on Fizeau's experiment, the single cogwheel is replaced with two rotating disks to measure the one-way speed of light. A single slit is cut out in the radial direction on each disk for the light to pass through the disk. With both disks rotating at the same angular speed, the light can pass through both disks only if the second slit is in a different radial direction from the first slit. The light takes time to travel from the first disk to the second disk. With both slits rotating into the straight path of light, the one-way speed of light can be calculated from the distance between two disks, angular speed of the disks and the angular difference between two slits.

23. Based on David Wineland's experiment in 1978, a laser beam points at an electromagnetcally trapped magnesium ion. The frequency of the laser light in the rest frame of the laser becomes a different frequency in the rest frame of the ion. If this new frequency matches the absorption frequency of the ion, the light will be absorbed by the ion. The wavelength is independent of reference frame. Therefore, the faster the ion moves toward the laser, the higher the frequency detected by the ion will be.

22. Based on Wilmer Anderson's experiment in 1937, the light detector is put in motion relatively to the mirror. Two light pulses are emitted from the mirror toward the detector. The elapsed time between two emissions is recorded on the oscilloscope. This elapsed time is larger if the detector moves away from the mirror faster. By comparing the elapsed time in the rest frame of the mirror to the elapsed time in the rest frame of the detector, the speed of light pulse in the rest frame of the mirror is found to be different from the speed of light pulse in the rest frame of the detector.

56. The frequency of sound is always different in a different inertial reference frame. The Doppler effect for sound wave and electromagnetic wave is not identical.

The main difference is the transmission medium.

The wavelength changes if the rest frame of the wave source is different from the rest frame of the transmission medium. Without the medium, the wavelength is invariant in inertial reference frames. The Doppler effect for sound, water, and electromagnetic wave depends on the transmission medium.

55. Woldemar Voigt had a theory of covariant wave equation in 1887. The Doppler effect can be applied to establish his theory if the speed of light can be assumed to be invariant in inertial reference frames.

Voigt's theory was ignored by Hendrik Antoon Lorentz and the contemporary but was picked up by Albert Einstein. The theory of relativity was finalized in 1905 with a fatal error.

45. The interference pattern of a Fabry-Perot interferometer is conserved in all inertial reference frames. Its constructive pattern requires the wavelength to be proportional to the gap width of the interferometer. The length contraction from Lorentz transformation assumes the gap of the interferometer to be contracted in the direction of the relative motion.

The wavelength is also contracted as it is proportional to the gap width. For two observers moving at the same speed, the contracted wavelength appears to be identical. If one of them moves in the opposite direction, they will observe an identical wavelength but two different frequencies due to the Doppler effect. Consequently, they observe two different speeds from the same light.

44. A standing wave can be formed in a microwave resonator if the length of the resonator is equal to one half of the wavelength multiplied by an integer. Two observers moving at the same speed will observe the resonator of the same length.

They will also observe the same wavelength as the wavelength is proportional to the length of the resonator. If one observer moves in the opposite direction, they will observe an identical wavelength but two different frequencies due to the Doppler effect.

Therefore, the apparent speed of the microwave appears to be different for these two observers.

43. The interference pattern from a Fizeau interferometer is conserved in all inertial reference frames. Its constructive pattern requires the wavelength to be proportional to the width of the interferometer at the point of interference.

The length contraction from Lorentz transformation assumes the interferometer to be contracted in the direction of the relative motion. The wavelength is contracted as well. For two observers moving at the same speed, the contracted wavelength appears to be identical for both of them. If one of them moves in the opposite direction, they will observe an identical wavelength but two different frequencies due to the Doppler effect.

Consequently, they observe two different speeds from the same light.

40. The observation of spectral shift in astronomy bears great similarity to the frequency shift in the Doppler effect. Both blueshift and redshift can be described by the movement of the double-slit interference.

In the rest frame of the star, the light passes through the slit to travel a straight path to reach the projection screen. The intersection of this path and the screen determines how the spectrum is shifted. If the screen moves away from the path, the spectrum will be shifted away from the center of the screen. This is known as redshift. If the screen moves toward the path, the spectrum will be shifted toward the center of the screen. This is known as blueshift. The spectrum not only shifts in position but also resizes proportionally.

The spectral shift is caused by the motion of earth in the rest frame of the star while the wavelength of the star light remains constant. The redshift places a maximum limit on the radial velocity of the remote galaxy. The galaxy can not be detected if the earth moves faster than the light in the rest frame of the galaxy. This is dark galaxy.

39. The observation of spectral shift in astronomy arises from the relative motion between the observed star and the earth. Both blueshift and redshift can be explained with the relative movement of the double-slit interference.

In the rest frame of the star, the light passes through the slit to travel a straight path to reach the projection screen. The intersection of this path and the screen is shifted by the movement of the screen. If the screen moves away from the path, the spectrum will be shifted away from the center of the screen. This is known as redshift. If the screen moves toward the path, the spectrum will be shifted toward the center of the screen. This is known as blueshift. The spectrum not only shifts in position but also expands in size.

The spectral shift is the result of the relative motion between the projection screen and the path of phase shift. It is not the result of any variation in the wavelength.

38. The double-slit interference shows that the product of the wavelength and the distance from the slit plate to the projection screen is conserved in all inertial reference frames. This conservation ensures that the observed wavelength in any inertial reference frame is identical to the original wavelength in the rest frame of the light source.

According to the Doppler effect, the observed frequency depends on the choice of inertial reference frame. With the same wavelength but different frequency, the speed of light is different in a different inertial reference frame.

36. The harmonic mode of standing wave requires the number of nodes to be conserved in all inertial reference frames. The half wavelength is proportional to the width of the microwave cavity. The same cavity width is observed by all stationary observers in the same inertial reference frame. All observers observe the same wavelength from the standing wave in a moving cavity.

According to the Doppler effect, the observer will detect a higher frequency if the microwave cavity is approaching. The observer will detect a lower frequency if the microwave cavity is receding. With the same wavelength but different frequency, the speed of microwave in the standing wave is different for different observer.

34. Parity symmetry maps one object to another object as inverse image. It shows that a displacement and its inverse image are of the same length. The length of a displacement is conserved in all reference frames. The wavelength of a wave is the length of the displacement between two adjacent crests. Therefore, the wavelength is conserved in all reference frames.

However, Doppler effect shows that the frequency of light is not conserved in all inertial reference frames. As a result, the speed of light is not conserved in all inertial reference frames.

32. The parity symmetry in physics connects the motions in two different reference frames. By examining the displacements in both reference frames, the length of the displacement can be shown to be conserved in both reference frames.

For two frames in relative inertial motion, the displacement is conserved in all inertial reference frames. For two frames free to accelerate, the displacement is conserved in all non-inertial reference frames. The length of a displacement is conserved in all reference frames.

The wavelength of a wave is conserved in all reference frames. The frequency varies with reference frame in Doppler effect. Therefore, the speed of light varies with reference frame. Light travels at different speed in different reference frame.

37. The speed of light is identical in all directions in the rest frame of the light source. In a different inertial reference frame, the direction of light may change due to the motion of the light source. The speed of light in the longitudinal direction of the motion of the light source is compared to the speed of light in the transverse direction. The result shows that these two speeds are equal only if the speed of the light source is greater than the speed of light.

35. The relative motion between a pair of observers represents a reflection symmetry. In the rest frame of first observer, the second observer moves at a distance away. In the rest frame of the second observer, the first observer moves with the same speed at an identical distance away but in the opposite direction. The reflection symmetry shows that the elapsed time in each observer's rest frame is conserved in both rest frames. The light takes the same elapsed time to move between two observers in both rest frames. However, the distance traveled by the light is different in different rest frame. With identical elapsed time but different distance, the speed of light is proved to be different in different reference frame.

7. A standing wave consists of two identical waves moving in opposite direction. In a moving reference frame, this standing wave becomes a traveling wave. Based on the principle of superposition, the wavelengths of these two opposing waves are shown to be identical in any inertial reference frame. According to Doppler Effect, a moving wave detector will detect two different frequencies on these two waves. Consequently, the wave detector will detect different speeds from both waves due to the same wavelength but different frequencies. The calculation of the speed of the microwave in the standing wave is demonstrated with the typical household microwave oven which emits microwave of frequency range around 2.45 GHz and wavelength range around 12.2 cm.

3. A standing wave consists of two identical waves moving in opposite direction. A frequency detector moving toward the standing wave will detect two different frequencies. One is blueshifted, the other is redshifted. The distance between two adjacent nodes in the standing wave is equal to half of the wavelength of both waves. Consequently, the wave detector will detect different speeds from both waves due to the same wavelength and the different frequencies. The calculation of speed is demonstrated with a typical household microwave oven which emits microwave of frequency range around 2.45 GHz and wavelength range around 12.2 cm.