Existence

Hi CS, The drivers reference frame inside the car is moving relative to what?That reference frame resides inside the car's reference frame and is at rest relative to the car's frame of reference.The car's reference frame resides in the Salt Lake Flats reference frame and is stated in the experiment to be moving at 0.5 c relative to the Salt Lake Flats.That would mean that relative to the Salt Lake Flats frame of reference the drivers frame of reference is moving at 0.5 c relative to the Salt Lake Flats reference frame.The laser pen is mounted at a 90 angle relative to the motion of the travel of the car relative to the Salt Lake Flats.The pulse (we can call 1 or two photons) leaves the laser pen traveling at a 90 angle relative to the motion of the car.When the laser pen sends the pulse traveling at a 180 angle to the laser pen it is directed directly at the D (detector).According to the laws of inertial that pulse must travel in a straight line from the point emitted in the direction the laser pen was pointed when the pulse was emitted.The direction that pulse is traveling can not be changed unless acted upon by an unbalanced force.For the pulse to hit the S instead of the D an unbalanced force must be applied to the pulse as it is in a vacuum.Therefore if the car is at rest relative to the D the pulse will strike the D.Likewise if the car is moving at 0.5 c relative to the D the pulse will strike the D.Now if you know of some unbalanced force that acts upon the pulse to change it's direction after it is emitted to cause it to hit the S please present that force and it's source.God Bless,

Hi Son, I had already had a look but I looked again.I can find nothing that changes what I believe the experiment as I have described would produce. You can find that in the post before this one I made to CS.God Bless,

Hi NoNukes, Maybe, maybe not.Does the driver have a reference frame inside of the car? Yes/NoDoes the drivers reference frame reside in the car's reference frame? Yes/NoDoes the car's reference frame reside in the Salt Lake Flats reference frame? Yes/NoIn my diagram is NoNukes standing on the Salt Lake Flats ? Yes/NoWould NoNukes observe the car moving to his right at 0.5 c? Yes/NoWould NoNukes observe the pulse emitted from the laser pen travel in the same direction the laser pen is pointing in? Yes/NoDoes the laws of inertial require that the pulse travel in a straight line in the direction the laser pen is pointed unless influenced by an unbalanced force? Yes/NoSo, what unbalanced force cause's the pulse to hit the S which is 2 feet to the right of the point the pulse is emitted, rather than the D which is directly beneath the laser pen when the pulse is emitted? The drivers reference frame resides inside the car's reference frame, having a coordinate system of it's own. They both have their own reference frame and either is in the others reference frame.But both are in the Sun's reference frame.God Bless,

Hi NoNukes, I was not refering to the video in the statement you quoted above.I was talking about the reference Son mentioned in Message 1013http://galileoandeinstein.physics.virginia.edu/...tclock.swf
http://einstein.byu.edu/~masong/htmstuff/Clock2.htmlI did view the the video and found it informing and a little amusing on occasions as the professor reminded me of my algebra teacher in school. Susskind was not discussing my experiment in his discussion.So no you both are not telling me the same thing.You are telling me that the pulse emitted from the laser pen when it is directly over the D will not travel in a straight line that the laser pen is pointed in as the laws of an inertial frame requires.The pulse must travel in a straight line unless altered by a unbalanced force. This is true in all inertial frames as that is what makes it an inertial frame.If a unbalanced force is applied to change the direction of the pulse the frame ceases to be an inertial frame.

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In his initial presentation of special relativity in 1905 he expressed these postulates as:[1]
The Principle of Relativity — The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems in uniform translatory motion relative to each other.[1]
The Principle of Invariant Light Speed — "... light is always propagated in empty space with a definite velocity [speed] c which is independent of the state of motion of the emitting body."

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SourceIn message Message 653 I said:

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2. Second postulate (invariance of c)

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As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body.

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Source

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Where have I changed that definition.I do require that the pulse travel in a straight line from the point emitted in the direction the laser pen is pointed at the time the pulse is emitted.That is not demanded by postulate #2 but is required for the frame to be an inertial frame, by postulate #1, as it comes from the laws of Newton.If you disagree present your argumentation.God Bless,

Hi Taq, I can't figure out how to draw the inside of the car with the tools I have.God Bless,

Hi NoNukes, So there is really no such thing as a reference frame.There is only a coordinate system in which there is an xyz coordinate that can be measured from the observer or object. The laser pen is attached to the frame on the rear of the car pointed toward the track the car is traveling on at 0.5 c.Now tell me or present an example of an observer that will observe the laser pen pointing in a different direction than at a 90 angle relative to the travel of the car on the tracks. Your non answers shows me that you are not willing to give an answer that can be confirmed or refuted.So I will try again and ask one question at a time.If the car is traveling at zero meters per second relative to the Salt Lake Flats, sitting on the track with the laser pen pointed at the D in my diagram and the laser pen emitts a pulse, will that pulse hit the D (detector)? Yes/NoOh I forgot you have already confirmed that the pulse will hit the D and the light will flash. So ignore that question.Let me ask the question that really gives me a problem.If the car is traveling at 149,896,229 meters per second relative to the Salt Lake Flats, on the track with the laser pen pointed at the D's and S's in my diagram and the laser pen emitts a pulse directly above the D, will that pulse hit the D (detector)? Yes/NoOh I forgot you already asserted the pulse will hit the S instead of the D it is directly over when the pulse is emitted. So ignore that question.So I will settle for an answer to the following question considering this quote.

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Newton's first law of motion is often stated as

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An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

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SourceDoes this law of Newton's require that the pulse emitted from the laser pen travel in the same direction the pulse is emitted in, unless the pulse is acted upon by an unbalanced force? Yes/NoIf your answer is 'No' please present your argumentation to support your view.God Bless,

Hi NoNukes, Oh I always consider that portion of the quotation.I just have never found what it is that the light is traveling c relative too.Einstein never said and you did not tell me when I asked you the question what the light was propagated at c relative too.Wouldn't that be the first thing required to come to a correct conclusion? So, does Newton's first law require that the pulse emitted from the laser pen travel in a straight line in the direction the laser pen is pointed when the pulse is emitted?God Bless,

Hi CS, But the experiment I am talking about is the one where the car has a frame mounted on the back with the laser pen at 4 feet from the S's and D's, pointed at the S's and D's that are attached to the center of the tracks, with the car traveling at 149,896,229 meters per second relative to the Salt Lake Flats.God Bless,

Hi CS, I thought an inertial reference frame had x, y, and z coordinates to be an inertial reference frame. The laser pen nor the detector exist in what you have drawn.The only thing that exists is the D which I assume is representing the driver and the Y representing what the driver could see directly in front of himself.God Bless,

Hi CS, The detector is mounted to the track and therefore is motionless within all frames if we ignore the Earth and it's movement which is less that the width of a human hair in the amount of time it takes the pulse to reach the detector after emitted from the laser pen.The laser pen is attached to a frame on the rear of the car and is therefore doing whatever the car is doing which is traveling at 149,896,229 meters per second relative to the Salt Lake Flats. The tracks are traveling at zero meters per second relative to the Salt Lake Flats, as they are attached to the Salt Lake Flats.Since the driver is in the car traveling at 149,896,229 meters per second relative to the Salt Lake Flats so the driver is traveling at 149,896,229 meters per second relative to the Salt Lake Flats.That means the driver as well as the laser pen is traveling at 149,896,229 meters per second relative to the detectors and sensors, which are attached to the track. The laser pen is attached to the car and does whatever the car does.The detector is mounted on the tracks the car is traveling over at 149,896,229 meters per second relative to the Salt Lake Flats.If you want to say the car is not moving and the tracks with the detector is moving at 149,896,229 meters per second relative to the car you can. You get the same results as the distance increases between the detector and the car by 149,896,229 meters per second.The point in the vacuum the pulse is emitted is also moving at 149,896,229 meters per second relative to the car. You get the same results as the distance increases between the point the pulse is emitted and the car by 149,896,229 meters per second. What is wierd about the pulse hitting the detector?Newton's first law says the pulse will travel in a straight line at c unless an unbalanced force is exerted upon the pulse.That being true the pulse will hit the detector every time the laser pen emitts a pulse directly above the detector, and all observers that can observe the pulse emitted from the laser pen will observe the pulse to hit the detector. As long as the pulse is not emitted from the laser pen you would be correct.The problem is the pulse is emitted into a vacuum at c directly above the detector traveling in a straight line the laser pen was pointed when the pulse was emitted. If the car is not moving the pulse will hit the detector.If the car is moving the pulse will still be emitted into a vacuum at c directly above the detector traveling in a straight line the laser pen was pointed when the pulse was emitted. The pulse will still hit the detector. The car moving at 149,896,229 meters per second relative to the Salt Lake Flats does not cause the pulse to miss the detector as the pulse travels in a straight line according to Newton from the point emitted in the direction it is emitted.Since there is no force in the vacuum to alter the direction of the travel of the pulse it will hit the detector everytime the laser pen emitts a pulse directly above the detector.The earth will move less than the width of a human hair in the amount of time it takes for the pulse to travel the 4 feet to hit the detector, so I don't think that will have any effect on where the pulse hit's the detector.God Bless,

Hi CS, So why did you present it as the drivers frame of reference then?The driver has no way of observing what you drew from inside the car. To observe the laser pen and the detector he would have to stop the car and walk around to the rear quarter panel and look at the frame the pen was attached too and the detector mounted on the track.God Bless,

Hi NoNukes, How can something be true and untrue at the same time?The design of the laser pen causes the beam emitted to go in a straight line in which the pen is pointed.That was not and is not the question I asked.I was asking about a pulse and since you don't seem to understand what that is I will further define it.If one or two photons are emitted from the laser pen into a vacuum, will those photons continue in a straight line in the direction the laser pen was pointed when they were emitted until they are scattered, regardless of what the laser pen does after the photons are emitted?Is the only thing that can change the direction of those photons an unbalanced force? It was not painful just very amusing thinking of him standing at the blackboard teaching.And BTW it was very informative, whether I agree with everything said or disagree with some of what was said.God Bless,

Hi CS, The question is according to the following diagram where does the pulse travel too when it is emitted from a specific point into the vacuum.

y = pen
S = sensor
D = detector
| = direction pen pointed when pulse emitted.
> = direction of car traveling at 0.5 c.
     |          |          |         |          |
     y          y          y         y          y
                |                      \
                |                        \
                |                        >>\>>>
                |                            \
                |                              \
     S          D          S          D          S   

                           N
                        NoNukes 

When the sensor sends a signal from the first S to the laser pen and causes it to emitt a pulse (photon if you prefer) at the second y will the pulse travel in a straight line to the D that is directly below the laser pen when the pulse is emitted?Or will the pulse travel at an angle as shown from the fourth y to the third S?That is the question.My contention is that if Einstein's postulate #1 and #2 are correct the pulse will hit the D everytime it is emitted at y.

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Newton's first law of motion is often stated as

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An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

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This quote is from the physics classroom found Here.That says an object.It does not say anything about a massive object. It mearly states object.An object is something that can be seen with the eye. I am not concerned with time-dilation at present.I am concerned and question how the pulse can travel at an angle other than a straight line when emitted from the laser pen in the direction the laser pen is pointed.Everyone seems to be telling me that it does travel at an angle except NoNukes. He keeps telling me it will hit the D sometimes and the S other times depending on the observer reference frame. At least that is what I get from his posts. The question is stated above and the diagram presented.Either the pulse will travel in a straight line in an inertial frame or an unbalanced force must be exerted upon the pulse to change the direction of the pulse.If you disagree then present your argumentation.God Bless,

Hi NoNukes, The pulse is released in a vacuum and travels only 4 feet in 4.066813452804019 nanoseconds until it hits the D, S, or the ground there is nothing in the vacuum to alter the photons or their direction. That statement does not compute.I don't care what direction I point my laser pen in the beam will hit the ceiling at exactly the point the laser pen is pointed at.If I am using the laser pen in a powerpoint presentation and I want to draw attention to a specific word I can point the pen at the word and press the button, holding the button down I can make a circle around the word or draw a line under several words or point to a specific picture.The beam always without fail strikes the point at which the laser pen is pointed.So I don't understand your statement. How can the photons go in a different direction than the direction the laser pen is pointed when the photons are emitted at c and satisfy the following statement?"an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force." Why not? The laser pen mounted on the frame on the rear of the car acts just like the one I have on my desk.Whatever you point it at the beam will hit.So do we agree that the photons emitted when the laser pen is directly over the D those photons will hit the D? The laser pen on the frame on the car is mounted at a 90 angle relative to the motion of the car and track. Therefore there is no need for aiming of the laser pen. It is designed in such a way that if the car is motionless relative to the detector mounted on the track and the pen is directly above the detector when a pulse is emitted it will hit the detector. I look forward to that display.God Bless,

Hi NoNukes, Glad to see you changed that from the original statement.Well you said one frame of reference could not be in another frame of reference.That seems only to mean there is only a coordinate system in which we determine the location of objects relative to other objects. That was the reason for my statement. I know your position is that it can hit either D or S.But since you made this statement in Message 1040:

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Assuming that the light pen is designed to emit light along the line of sight as shown in the diagram. Then I agree that the light beam will continue along the line of sight regardless of the motion of the source.

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How can the photons, not a light beam travel in a straight line from the point emitted and hit the S?I will agree if you turn the laser pen on there will be a solid line reflected off the ground in the direction the laser pen is pointed. Just like the one I can draw during a powerpoint presentation.The problem is in this experiment there is only a pulse which is very short (a very few photons) emitted from the laser pen that travels in a straight line and hits the D. I await your digaram you mentioned of moving frames. Sorry you didn't catch any fish. But if you are like me just getting out in the environment is very relaxing.Starting this weekend I will have very little time for a couple of weeks to be online as I will be traveling to Texas and back so don't expect much from me.So take your time and do a good job on your diagram of moving reference frames.God Bless,