Existence

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,

Yes, when I posted that I hadn't realized that you had moved to a different example. You should know that if you're reading this thread. What are you trying to achieve here?What is the question? If you had read the thread, you would have realized that I was talking about the previous example and not just wasted all that time typing this stuff. Newton's first law is about massive objects, not pulses of light. It doesn't apply here. You're way over-complicating this, if you're just trying to understand time-dilation and how we know of it.Again, what is your goal in posting these messages? Are you trying to understand something specifically?You've got way to much fluff and not enough content. Cut to the chase.

ICANT has a hypothesis regarding existence and theology that apparently requires that time dilation not exist. He has shown a willingness to promote any number of crank theories rather than accept SR or GR.I think he's already painted himself into a corner. His current goal seems to be to delay understanding.

Hi ICANT.I see you've asked me the same question once again. My answer is the same. You are butchering the law of inertia. The photons will continue along an original direction of travel unless reflected, refracted, diffracted, scattered, etc. The "direction in which the laser beam is pointed" may or may not be the same thing as the direction in which the photons emitted. The law of inertia says nothing about traveling along a pointing direction.And like every other path for an object moving at finite speed, the angle of a path of a photon within the laser beam as measured using the coordinate system of the frame will vary with the reference frame. And once the photon exits the light pen, absent some relevant event/phenomenon, the photon will continue to travel in the same direction. But the direction of a photon will not be the same in every reference frame. Only the speed will be the same in every reference frame.Let me provide an example method for aligning a light pen.Let's say that we align the laser pen by sighting along the barrel of the pen as shown in the diagram below: 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. Note that as shown in the lower diagram, the path of the photon is determined within the light pen and not externally.My plan is to generate a moving display of reference frames to show what a coordinate transform looks like. But I went fishing today. I'll do it later.

Hi ICANT Wrong, ICANT. Surely you know that an answer that denies that reference frames exist won't fly with me.I suggest reviewing your definitions again. A reference frame includes a coordinate system. It's perfectly fine to say that the reference frame is the coordinate system. The "measured from an observer or object" phrase is just gibberish. We assign coordinates in a rectilinear coordinate system by projecting the position vector for a point in space onto the coordinate axes. There may or may not be a person or object at the origin. There is no need to post stuff that you want me to ignore. But I do appreciate the peak into your somewhat non-linear thought processes. First you accuse me of ducking your question, and then you admit that I have indeed answered your question. Cute, but why not just delete that junk.But to be perfectly clear, I actually said that the answer to where the photon will strike is ambiguous because the problem statement is ambiguous. Answers of either S or D can be defended. I'm perfectly happy to use D for the purpose of illustration.I have further indicated that when the problem is properly analyzed using special relativity, that the photon would strike neither S nor D. But we cannot even get to the point of using special relativity while you are still denying Newtonian physics.For the purposes of discussion, let's use continue to use the D answer. Haven't I already provided such examples? There are an infinite number of such frames. I'll describe two frames that meet your stated requirements.Let's assume, as I did in previous messages that the laser pen emits a photon that travels vertically as observed by any observer at rest in the track frame of reference. That yields your preferred answer that the photon strikes detector D. Let's use the observer located at NoNukes in your diagram as the origin point of the track coordinate system.As measured in any and every frame of reference that is moving in along the tracks at any speed relative to the salt flats, the photon will not be moving vertically as measured using the associated coordinate system of that frame. Otherwise, the photon could not strike D using the coordinate system of that frame.An example frame of reference would include a reference frame with its origin fixed on the trunk lock of the car and moving along with the car at 0.5 c. Ignoring special relativity, the photon must travel at a 26.5+ degree angle in that coordinate system in order to strike D. A second example would be a frame of reference with its origin moving at 0.25 c relative to the salt flats but in the opposite direction of the first car. In that coordinate system, (again ignoring special relativity), the photon must travel an angle of 14+ degrees from vertical in order to reach D. The observed angles for the two frames would not be the same, and neither angle will be ninety degrees. Finally a reasonable statement of Newton's law from you.Newton's law of inertia does not apply to massless particles. Nonetheless, absent some phenomenon, the photon will not change direction, but will continue in a straight line at least to the extent that the photon acts like a particle. But that direction will not be measured to be the same in two different reference frames having parallel axes, but moving relative to each other.Let me restate. The photon travels at a constant angle as measured in a particular coordinate system, but the angle is different in different coordinate systems. Using the example above, the track observer could say that the photon was emitted vertically and continued on a vertical path to strike detector D. The car observer would say that the photon was emitted at an acute angle from vertical, and continued along that path to strike detector D.Let's briefly discuss postulate #1 which requires that true "laws of physics" be the same in every inertial reference frame. When we apply postulate #1, we consider only measurements made using the coordinate system associated with the frame. The postulate does not apply to a mix of measurements made in different frames. Where there is relative motion between frames, measured velocities, angles, energies, etc. of the same particle on a given trajectory may not agree with the same parameter measured in a different reference frame, except that objects traveling at speed c must, because of postulate 2, travel at speed c in any and all inertial frames. The latter postulate is what makes the speed of light in a vacuum different from the speed of ordinary, slow moving objects.I'm done. Too tired to continue. I caught zero fish, but I did learn how to make a decent cast.Edited by NoNukes, : grammar

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.

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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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:

quote:

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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,

How did you deduce THAT from Nonukes statement? It's pretty dishonnest from you to affirm this can be deduced from what he said (not that any honnesty could be expected from you).Tell me ICANT, how can you be "in" or "out" of a reference frame? Knowing that a reference frame is a system of coordinates with axis that extend indefinitely, meaning that any objects (or points) will have coordinates in any reference frame you could choose to use.Edited by Son, : No reason given.

Really? So regardless of the angle at which the beam is aimed, you claim that it will reach the ground in 4.00668 nanoseconds. Forgive me if I require more than your say so. Exactly so. And what you've described is exactly the procedure used to aim a laser beam at that sensor on top of the pole.But what we are discussing is decidedly different. Namely, how do you describe the "angle" at which a light pen is pointing when the target and the source are in different inertial reference frames. Anyone can describe the simple situation involving pointing a laser pen at a black board. I'm not disputing this for the purpose of this discussion. I want to follow through on the ramifications of the laser beam striking point D as measured from diverse reference frames. There is very little point in continuing to ask me this question twice a day. You should consider the statement above in light of postulate #1. If you really understood that postulate, this discussion would have ended about 500 posts earlier. I believe Taq actually pointed out this issue out over a week ago.Consider the following.One of the ramifications of postulate #1 is that it is impossible to design an experiment to measure absolute motion. Only relative motion can be detected. But if the laser pen works as you suggest, then every light source is an absolute motion detector. Based on your description, if you were in an enclosed car moving at 0.5c relative to the salt flats, and you aimed your laser pen at a point on the blackboard, photons would strike a point somewhere behind your aiming point on the blackboard simply because the car is moving. Your description actually violates the postulate that you insist is correct.I don't see anything unique in your other posts so far, so I'll likely just acknowledge them.

Why are you asking? You're wrong.By "massive", I didn't mean "really big"... I meant "contains mass". Photons are not "objects" in classical physics.Too, you can't "see a photon with your eye"... you're eyes use photons to see objects. Do you accept that it occurs? What is it about your worldview that causes you to want to deny that time-dilation exists? Well that depends on the pen. If the laser isn't uni-directional, then the pulse could be traveling in all direction like one emited from a lightbulb.Too, its depends on your reference frame. If I'm standing on the gound as you fly by in the car shotting a laser beam, it'll look to me like the path of the pulse is different from the one you observe in your reference frame. That's part of the wierdness of light. Maybe you're misunderstanding him? He seems to have a great grasp of the physics here. No, that sounds correct.

Do you know why his theology requires that?

Your statement is without reason. Reference frames are infinite in extent and they are not containers. I'm not accountable for your failure to understand that. You don't seem to understand Susskind's explanation any better than you do mine. Kinda. There was quite a hike involved, and I found myself to be in poor physical shape. But at least the company was good. I don't care all that much about fishing.With regards to the diagrams, I've been messing around with some animation software in connection with an iPhone app I'm working on. I should be able to produce an animated gif showing some moving reference frames. I'm sure I'll have something up before you return.

No. I don't fully understand ICANT's position. ICANT started this existence thread after becoming frustrated with arachnophilia over the literal meaning of Genesis 1:1 in another thread. The argument in this thread evolved to a disagreement over the nature of time. For some reason that makes little sense to me, ICANT believes that the view of time that underlies SR and GR is incompatible with his own view of the beginning of existence.