Existence

Frames of reference aren't relative, they're what things are moving relative to. The frame of reference is the coordinate axis by which we measure position in over time. A frame of reference has its own X, it's own Y, it's own Z, and it's own t (time.)A moving frame of reference has coordinate axes that implictly have their own velocity vectors, but since everything in that frame of reference has that same vector component we can ignore it. But when we translate from one coordinate system to another - when we shift from the observer inside the car to the observer standing motionless outside it as it drives by - then, to chart the position of objects in the new coordinate system, we have to add in the velocity vector of the reference frame.Everybody knows that, instinctively - if you toss a tennis ball from a car moving 100 mph, then it hits the target at whatever velocity you tossed it plus whatever velocity the car had. And this is vector addition, not number addition, so both speed and direction get added in. That's why if you toss the tennis ball behind the car instead of in front, it hits at a lower speed than 100 mph - you've added a negative velocity with respect to the forward velocity of the car because the tennis ball has moved from the reference frame of the car to a new reference frame. Not because it's stopped being attached to the car, but because the tennis ball has been accelerated - its velocity has changed over time.

Where did the pule originate? When did it leave it's initial reference frame (the frame the car is in)? How did it excape said reference frame? No, the pulse is traveling at .5c relative to the salt flats SINCE IT IS IN THE CAR'S REFERENCE FRAME.

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"Why don't you call upon your God to strike me? Oh, I forgot it's because he's fake like Thor, so bite me" -Greydon Square

The one sending the light pulse to the detector. We are using the car's reference frame, not the reference frame of the Salt Lake flats. Again, we are not using the reference frame of the Salt Lake Flats. We are using the car's reference frame. In this reference frame, the pen laser and detector have zero velocity. They are not travelling anywhere. Completely false. The only frame that matters is the one that the observer is in. Since we are using the driver in the car as the observer the frame that matters is the car's frame of reference. Then why do you keep insisting that it will miss the detector?ABE:The laws of physics are the same for all observers in uniform motion relative to one another (principle of relativity),
Theory of relativity - WikipediaThe car is in uniform motion. The observations made in the car should be the same as in any car going at any constant velocity, even if that velocity is zero relative to the Salt Lake Flats.Edited by Taq, : No reason given.

Not quite right. Although it seems counter-intuitive, light always travels at 'c' as measured in any inertial reference frame (at least when propagating in a vacuum, but approximately so even in air). Resolving the issues presented by this experimentally verified fact is what special relativity is all about.The only way objects enter or leave a reference frame is when they are created or destroyed.

Dammit! I knew that. Chalk this one up to my being very ameteur when it comes to any of this stuff. Thanks for the correction though. I know this. i was asking ICANT so he would explain how all of a sudden the light was in the Salt Flats' frame and not the car's.

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"Why don't you call upon your God to strike me? Oh, I forgot it's because he's fake like Thor, so bite me" -Greydon Square

I think it is important to be clear about this. The laws of physics are the same in every inertial frame as is the speed of light in a vacuum as measured in the coordinate system of any and every inertial frame. But the momenta, energies, etc. of objects (and photons for that matter) and the durations of events as measured/observed in different inertial reference frames may well differ.

Are you sure that ICAN'T is ready for the second part? Perhaps it is best to establish that there is no golden point of reference in the universe from which everything else is measured before introducing observations that are made from different inertial frames.

Of course not. He'll never be ready. But I don't see any point in writing things that need to be corrected later. I also don't want to confuse other readers who are ready.ICANT does not understand what a reference frame is. His recent suggestion that some inertial reference frames don't matter and his request to know what some reference frame was "relative to" are clear evidence of that.But the fact that different measurements and observations are the reality for different inertial frames coupled with the fact that no inertial reference frame is special is pretty much central to understanding SR and to the discussion at hand. Discussing those things cannot be avoided.

ICANT, I think you should seriously go see a high school science teacher and ask him to teach you about inertial frames. It doesn't seem us trying to teach you through internet helps you.I'll try again anyway....
A frame of reference is a system of coordinates from which you can take measurements. It's not a material object like a car that you can enter or leave.
The laser pen is "in" all reference frame you can imagine (the car''s, the Earth's, the Sun's, etc...). That's why this:"The only frame that matters is the one the pulse is in." doesn't make any sense.edit: I assumed in my explanation that you knew what a system of coordinates is, if you don't know, feel free to ask. Since we already made the same mistake when we assumed that you knew what an inertial frame was, I don't want to make the same mistake again.Edited by Son, : No reason given.

Hi Son, A frame of reference.It could refer to a coordinate system or it could refer to a set of axes within which to determine the location of objects.

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A frame of reference in physics, may refer to a coordinate system or set of axes within which to measure the position, orientation, and other properties of objects in it, or it may refer to an observational reference frame tied to the state of motion of an observer. It may also refer to both an observational reference frame and an attached coordinate system as a unit.

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Source

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In physics, an inertial frame of reference (also inertial reference frame or inertial frame or Galilean reference frame) is a frame of reference that describes time homogeneously and space homogeneously, isotropically, and in a time independent manner.[1] All inertial frames are in a state of constant, rectilinear motion with respect to one another; they are not accelerating

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SourceA inertial frame of reference is one in which the motion of a particle not subject to forces is moving in a straight line at constant speed.So when the pulse leaves the laser pen it it in it's own frame of reference.At the moment it leaves the laser pen:There is distance between the pulse and the laser pen attached to the car.
There is distance between the pulse and the pole attached to the car.
There is distance between the pulse and the detector extended from the pole that is attached to the car.
There is distance between the pulse and the Salt Lake Flats.Therefore the pulse is in an inertial frame of reference as it is traveling a "c" at a 90 angle to the motion of the laser pen source of the pulse.Since the pulse in it's own frame must travel in a straight line at "c" and the pulse observes the car traveling at "0.5 c" at a 90 angle to it's motion the pulse will miss the detector, because the detector will have moved 2 feet relative to the position the pulse was emitted at the moment it was created, before the pulse reaches 4 feet in height relative to the position emitted from.The same principle would be observed in the open light clock on the cycle and the flatcar.God Bless,

No it isn't. It is in all interial reference frames.We are focusing on the observation of the light pulse in the inertial frame of the car. In this inertial frame there is no relative velocity between the pen laser, the detector, the car, or the observer. They are all in the same inertial frame with zero relative velocity. Therefore, the light pulse will strike the detector dead center. No, the detector does not move at all in the car's inertial frame as described above.Edited by Taq, : No reason given.Edited by Taq, : No reason given.

Hi ICANT,I think you've taken up a topic that will summarize the differences you have with some of the SR supporters. Wrong, ICANT. No object is ever limited to being in only its own reference frame.Nothing in the definitions you've posted says anything about entering or leaving a reference frame. There is also nothing in the definitions that localizes a frame of reference to an object or particular point. That stuff is baggage you've invented. At most, the origin (0,0,0,0 point) of the origin can be fixed. Son and crashfrog's explanations are perfectly proper.The pulse (and every other object/event) is "in" every inertial frame conceivable during the entire time that it exists. Even if the pulse cannot be seen from some vantage point at rest in a particular inertial frame, the pulse still has coordinates and a velocity as measured using the coordinate system or the coordinate axes of that frame, and what's more to the point, every observer at rest in that frame will agree on the velocity and coordinates once they agree on the coordinate axes.The pulse never leaves the inertial frame of the salt flats, the car, or any other inertial or non-inertial frame no matter how distant it becomes from some object or observer.As an additional aside, those experienced with relativity know that it almost never helpful to talk about reference frames that are moving at speed c relative to any observers. After all, photons always move at speed c with respect to other inertial observers, so looking at things from the photon's perspective does not usually produce anything interesting. No sentient being ever moves at speed c. Instead it is the reference frame of the observer that is of interest.There is no way to accurately describe what postulate #2 means using your understanding of inertial frames of reference.Edited by NoNukes, : No reason given.

Hi NoNukes, Who said an object could be limited to being only in its own reference frame.I do believe all objects will have their own reference frame. Concepts such as time do not have their own reference frames.The pulse would be in the cars reference frame which would be in the Salt Lake Flats reference frame which would be in the Earth's reference frame which would be in PlanteX's reference frame and all of it would be in every other reference frame in the universe. I think we are almost agreed that the object pulse emitted from the laser pen can be in every reference frame in the universe.It seems you can not accept that the object called a pulse can be in it's own reference frame.The pulse is in a vacuum. It is not in the car, or in a tube.
The pulse is traveling at the constant speed of "c".
The pulse would observe the car going at a 90 angle to it's own travel.
The pulse would observe there was distance between it and its source.
The pulse would observe there was distance between itself and the pole that was moving away from it's path of travel.
The pulse would observe there was distance between itself and the detector it was supposed to strike and that distance was increasing.
The pulse would observe that the detector had moved 2 feet in the direction of the motion of the car the pole the detector was attached too had moved at the observed "0.5 c" speed the car was moving at a 90 angle relative to the pulses direction of travel, before it could travel 4 feet from its point of beginning to exist.So are you saying the object called a pulse which is traveling at a constant speed of "c" which can locate objects in other reference frames relative to itself is not in a reference frame of it's own?If I understand your position the pulse can not have a reference frame of it's own as it began to exist in the cars reference frame.If that is true then the car can not have a reference frame of it's own as it began to exist in the Earth's reference frame, so the car would exist in the Earth's reference frame.But then further investigation shows that the Earth could not have a reference frame of it's own as it began to exist in the universe and so would be in the universe's reference frame.But still further investigation shows that the Universe began to exist in the singularities reference frame and thus it would exist in the singularities reference frame.But then further investigation shows that the singularity began to exist in the mathematical equation that can not say what exists at that particular point.Which brings me back to the question in the OP.

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If existence is not responsible for bringing into existence all that exists, then what is?

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There is existence (all things exist) and the opposite of that is non-existence (no thing exists). There is no known mechanism whereby existence can begin to exist from non-existence.

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Can anyone present a case for existence without it being brought about by existence?

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Then how can the speed of light be the same for all observers regardless of their velocity?

The observer is what defines the reference frame. In our example, the observer is in the car. The pen laser and detector are at rest with repsect to the observer. They are not moving with respect to the observer. The pulse is not the observer. The driver is the observer. Please use the driver's frame of reference. The pulse can hit any object, even those that are moving relative to the observer. However, in the driver's frame of reference neither the pen laser or detector are moving so the pen laser and detector are in the driver's inertial frame. For the driver, the observations will be the same no matter what velocity he has with respect to the Salt Flats as long as the car is moving at a constant velocity.