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Thread: A light speed gedanken

  1. #41
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    The photon velocity can be perpendicular in one frame, just not in both frames. I suspect Cangas thinks that perpendicular in one frame means perpendicular in all, which would lead to reception by the receiver in one frame but not in another.

  2. #42
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    Quote Originally Posted by CANGAS
    TomTom:

    You get a solid "F".
    Since when does the student grade the teacher?

    Sherlock should be your nick.
    "Illiterate dunce" should be yours. Try reading my responses for a change, instead of reflexively disagreeing with them. Any moron can do the latter.

    But then you failed to properly address the real issue, as I thought would be so, : the motion of a photon emitted perpendicular to its moving source.
    No, I did address it, and properly at that. The motion of the photon is not perpendicular to the motion of the source from the Earth frame. Period. It's not my problem if you're too dimwitted to see that.
    Last edited by Tom2; 05-06-06 at 10:08 AM.

  3. #43
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    Quote Originally Posted by CANGAS
    The starship is traveling at .99c, according to the stationary observer. The photon travels a short distance perpendicular to the starship motion when the pipe, travelling at .99c, runs into it from the side and absorbs it.
    Of course not. Your mistake is classic frame-mixing. You're assuming that the velocity of the photon in the Earth frame is the same as it would be in the ship frame. That's obviously wrong. In fact I even gave you the correct answer in this very thread.

    The velocity of the photon in the Earth frame is (c/γ )i+vj. Just work out the Lorentz transform for the photon's velocity vector. It's not difficult.

  4. #44
    Quote Originally Posted by CANGAS (in "Absolute Reference Frame")
    The immediately prior conversations between us concerned your (mis)comprehensions regarding Relativity, not mine.
    Have you forgotten this conversation, CANGAS? Or do you just wish you could forget it?

  5. #45
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    Aberration of light will cause the photon to be absorbed by the wall of the tube. Look up aberration of light on the internet. The velocity of the emission source has no effect on the lights path.

  6. #46
    Please use Sugar Cane Alcohol Billy T's Avatar
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    Quote Originally Posted by Tom2
    Of course not. Your mistake is classic frame-mixing. You're assuming that the velocity of the photon in the Earth frame is the same as it would be in the ship frame....
    You are of course fully correct, but I would suggest next time you need to explain this, say:
    " You're assuming that the Direction of travel of the photon in the Earth frame is the same as it would be in the ship frame." The speed is of course the same in both frames. Unfoturnately, too many people here think speed and velocity are the same and they may not have understood you.
    Last edited by Billy T; 06-01-06 at 12:02 AM.

  7. #47
    Quote Originally Posted by Montec
    Aberration of light will cause the photon to be absorbed by the wall of the tube. Look up aberration of light on the internet. The velocity of the emission source has no effect on the lights path.
    Hi Montec,
    Aberration of light means precisely that the velocity of the emission source relative to the receiver has an effect on the light's path. As Earth's motion changes throughout the year, the velocity of stars relative to the Earth changes, so telescopes must be pointed in a slightly different direction to catch the starlight.

  8. #48
    The Devil is in the details
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    Pete, remember the star is stationary, it is not moving (the 'fixed' stars). Photons travel in a straight line toward the solar system. The Earth moves through this 'photon rain' in a circle, its orbit around the sun. It is easy to imagine the photons as rain falling straight down. When the car (Earth) moves through this rain, the rain falls at an angle. If you were to mount a tube to your car pointing straight up, the rain would fall through the tube without contacting the sides while the car was stationary, but would hit the sides of the tube if the car is in motion.

  9. #49
    Pete, remember the star is stationary
    "stationary" is relative. Aberration is due to relative motion, not absolute motion.
    If aberration were due to absolute motion rather than relative motion, then the ether wind would be detectable in the Michelson Morley experiment.

    Quote Originally Posted by 2inq
    The Earth moves through this 'photon rain' in a circle, its orbit around the sun. It is easy to imagine the photons as rain falling straight down. When the car (Earth) moves through this rain, the rain falls at an angle. If you were to mount a tube to your car pointing straight up, the rain would fall through the tube without contacting the sides while the car was stationary, but would hit the sides of the tube if the car is in motion.
    Right - in this case you've chosen the Sun's rest frame so the Sun is stationary and the Earth is moving. But the analogy works just as well for a moving source, if you imagine photons from a source as drips falling from a leaky bucket:

    1) Stationary receiver, stationary source
    When the car is stopped under the bucket, the drips fall straight down. If you were to mount a tube to your car pointing straight up, the drips would fall through the tube without contacting the sides.

    2) Moving receiver, stationary source
    When the car drives under the bucket, the drips fall at an angle. If you were to mount a tube to your car pointing straight up, the drips would hit the sides of the tube.

    3) Stationary receiver, moving source
    The bucket is mounted on a track that moves the bucket forward at driving speed.
    When the car is stopped and the bucket passes overhead, the drips fall at an angle. If you were to mount a tube to your car pointing straight up, the drips would hit the sides of the tube.

    4) Moving receiver, stationary source
    When the car is drives at the same velocity as the bucket, staying directly beneath it, the drips fall straight down. If you were to mount a tube to your car pointing straight up, the drips would fall through the tube without contacting the sides.
    Last edited by Pete; 06-01-06 at 12:47 AM.

  10. #50
    The Devil is in the details
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    Quote Originally Posted by Pete
    "stationary" is relative.
    Right now I'm stationary... relative to the Earth's surface. If aberration were due to absolute motion rather than relative motion, then we'd have to compensate for it differently when pointing telescopes at Saturn, for example.
    I think you are confusing the Earth's rotation with the Earth's orbit around the sun. The stars and the planets seem to move across the sky due to Earth's rotation. Stellar aberration is due to the motion of the receiver, the telescope. Special Theory has a confusing method of trying to explain aberration to eliminate the preferred frame of reference.

  11. #51
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    Hi Pete

    How would an emission source know the velocity of all possible recievers. What I'm getting at is that light travels in a straight line after it is emitted. If a source can emmit light at angles that vary depending on any type of velocity then what can cause this effect.

  12. #52
    Quote Originally Posted by Montec
    How would an emission source know the velocity of all possible recievers.
    It doesn't, of course!
    What I'm getting at is that light travels in a straight line after it is emitted.
    Yes...
    If a source can emmit light at angles that vary depending on any type of velocity then what can cause this effect.
    No, the angle that you receive it at depends on your motion. See the bucket and car analogy.

  13. #53
    Quote Originally Posted by 2inquisitive
    I think you are confusing the Earth's rotation with the Earth's orbit around the sun. The stars and the planets seem to move across the sky due to Earth's rotation.
    I don't think you got what I was saying. I've edited the post while you were replying... have another look.
    Stellar aberration is due to the motion of the receiver, the telescope.
    It is due to the motion of the receiver relative to the source. A moving source also cause aberration. See bucket and car analogy.
    Special Theory has a confusing method of trying to explain aberration to eliminate the preferred frame of reference.
    You think the bucket and car is confusing?
    Last edited by Pete; 06-01-06 at 01:43 AM.

  14. #54
    The Devil is in the details
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    Pete,
    4) Moving receiver, stationary source
    When the car is drives at the same velocity as the bucket, staying directly beneath it, the drips fall straight down. If you were to mount a tube to your car pointing straight up, the drips would fall through the tube without contacting the sides.
    I'll just concentrate on this example, but no. (3) was incorrect, also. Think again about this example (4). The drop of rain might fall straight between the bucket and car, but the photon will not. The photon does not carry tranverse motion. Aberration will be evident in the tube attached to the car. When the photon enters the top of the tube, the tube is in one location. As the tube moves forward, the photon will move toward the side of the tube as it travels down the moving tube. If it didn't, no such thing as aberration would exist! Put a T1 at the top of the tube and a T2 at the bottom of the tube. The photon takes X amount of time to move from T1 to T2, in which time the tube has advanced forward. As I said, the observation of aberration is the proof of its existence.

  15. #55
    Quote Originally Posted by 2inquisitive
    Pete,
    I'll just concentrate on this example, but no. (3) was incorrect, also. Think again about this example (4). The drop of rain might fall straight between the bucket and car, but the photon will not. The photon does not carry tranverse motion.
    Yes they do. Why wouldn't they?
    Aberration will be evident in the tube attached to the car. When the photon enters the top of the tube, the tube is in one location. As the tube moves forward, the photon will move toward the side of the tube as it travels down the moving tube. If it didn't, no such thing as aberration would exist!
    Sure it would - just as in cases 2) and 3). Aberration occurs when there in relative motion between the source and the receiver.

  16. #56
    The Devil is in the details
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    Pete, how about aberration of light from the moon? The moon has an angular velocity (relative) across the sky.

  17. #57
    Yes, light from the Moon to Earth will have an aberration of about 2/3 of a second of arc for a telescope at the South Pole, and about half that for a telescope on the Equator. This corresponds to about 1 km on the Moon's surface.

    I don't know if that would be detectable, or if anyone has tried.

  18. #58
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    Hi Pete

    Regarding these two examples:

    2) Moving receiver, stationary source
    When the car drives under the bucket, the drips fall at an angle. If you were to mount a tube to your car pointing straight up, the drips would hit the sides of the tube.
    3) Stationary receiver, moving source
    The bucket is mounted on a track that moves the bucket forward at driving speed.
    When the car is stopped and the bucket passes overhead, the drips fall at an angle. If you were to mount a tube to your car pointing straight up, the drips would hit the sides of the tube.
    Would not the angle of the tubes be reversed in these two examples if you wanted to catch the rain?


  19. #59
    The Devil is in the details
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    Quote Originally Posted by Pete
    Yes, light from the Moon to Earth will have an aberration of about 2/3 of a second of arc for a telescope at the South Pole, and about half that for a telescope on the Equator. This corresponds to about 1 km on the Moon's surface.

    I don't know if that would be detectable, or if anyone has tried.
    Thanks, Pete! You have just given me the way to prove my hypothesis. Actually, just before this post when you kept insisting aberration was due to relative velocity only, as per Special Theory. I got me to think about something I had read before. There is no aberration of moon light. I had read that before I arrived at my hypothesis and didn't think of the consquences at the time. So, I started looking for examples and guess what I came across? Solid evidence for my hypothesis, against Special Theory AND all other theories I am aware of.

    What is this evidence? Lunar Laser ranging! Remember the retro-reflectors the Apollo astronauts left on the moon? Five in all, four of which are still working. I am doing this from memory now, but I will get more detailed analysis when I have time. What it boils down to is this. When scientist send a laser beam to the moon to hit a retro-reflector, they send the laser through a telescope to keep the laser beam from dispersing as little as possible. When the laser arrives at the moon, it is about 7 kilometers in diameter. Even then, only a small percentage of the laser beam actually hits the retro-reflector to be reflected back to Earth. The beam is about 20 kilometers in diameter when it arrives back at Earth, since the retro-reflector does not return the beam through a telescope. Do you know how a retro-reflector works? It returns a laser beam back along the exact same path it was recieved from, using what I think are called corner prisms. In other words, a laser beam that hits the retro-reflector at an angle, say 10 degrees, is not reflected back at an additional 10 degrees for a total of 20 degrees, but instead back to the exact same location it was recieved from. Guess where the scientists aim the laser? Exactly at the chosen retro-reflector's location. Light takes 1.25 seconds, on average, to reach the moon and another 1.25 seconds for the return trip. If relative velocity between the moon and the Earth were a factor, the moon would 'really' be located ahead of its apparent position. But its not. The laser is amed straight at the retro-reflector, and the return beam arrives back at exactly the emitter's location! How can this be??? My hypothesis explains it. As far as I am aware, my model, or possibly someone else that is using the identical model, is the only one that explains the observed fact. In my model, the ether is dragged around with Earth's rotation, similiar to Earth's atmosphere, except the ether is dragged far above the atmosphere by Earth's gravitational field. Earth's gravitational influence obvously extends past the moon's orbit, as the moon orbits the Earth. The moon also has a gravitational field, extending to the Earth, which also drags the ether. The effects of Earth's drag and the moon's drag on the ether cause the ether to 'follow along' between the two gravitating objects. Light travels through the ether in a more or less straight line between the Earth and the moon. Gravity travels in a more or less straight line between the Earth and the moon and the ether follows the gravitational interaction. The light follows the gravitational interaction (ether), thus the straight shot of the laser to the retro-reflector and back. The laser beam would not do that if Special Theory's relative velocity explaination is used, the laser beam would not do that if a 'lumniferous' stationary ether model were used. But the 'ether drag' of the Earth does not effectively extend to distant stars. The Earth and the dragged ether moves through the light waves emitted by the distant stars, so an aberration is observed in that case. When I call this 'my hypothesis', I do not literally mean it belongs to me, it is just a model that works to describe observation and experiment accurately. There may be others with similiar or identical theories that are mathematically supported, I am just not aware of any exactly like mine, including the decreasing density of the permittivity and permeability of the vacuum over time due to the expansion of the universe. Of course, the permittivity and permeability of the vacuum is a direct consequence of the density of the ether in my hypothesis. I also think 'dark matter' and 'dark energy' can be explained by this model, but that is a long discussion not relavant at this time.

  20. #60
    Quote Originally Posted by Montec
    Would not the angle of the tubes be reversed in these two examples if you wanted to catch the rain?

    Yes. Because the velocity of source with respect to receiver is reversed.

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