I would like to add that if LET makes all the same predictions, it would also predict that each rockets returns home while home is still in the past, as your simulation depicts, so LET would also be disproved by this (invalid) argument.
David Cooper wrote: ↑September 2nd, 2018, 6:11 pm
Of course there's a contradiction there - it comes in as soon as you endorse the SR specification which demands that no frames have a higher status than any others. By denying an absolute frame, you automatically have contradictions in that every acceleration is also a deceleration
Interesting. Acceleration is a vector rate of change in velocity, not a change in speed. There is no difference between acceleration and deceleration. The ISS for instance is always accelerating, yet its speed remains constant (relative to Earth). This is high-school physics, not even touching on relativity.
and every such change in speed leads to a clock both running slower and speeding up at the same time. These are contradictions that cannot be tolerated by anyone rational.
This part however touches on relativity. Speed is defined within a frame, and within that frame, the clock rate is dilated in accordance to that one speed. In a different frame, it might be dilated less. So I suppose a velocity difference would result in a larger and smaller speed in different frames (and corresponding time dilation),
but that is not 'in the same way', so not a violation of the law of non-contradiction.
You'll need to expand on that, because it doesn't appear to fit with relativity at all (any version). The measured time between events varies widely for different frames.
Time is just one component of 4D spacetime. An event is a point in that 4D space, and regardless of the IRF chosen, the separation between any two such points (called the interval) is a fixed value. It might be pure space, pure time, or a combination of both, depending on the arbitrary orientation of the 4 axes.
I just brought it up as an example of something that is frame-independent.
I can't make out whether your point is an objection or not. Rotating the axes produces a different coordinate system in which the speeds of all objects are measured to be exactly the same as in the previous one.
You seem to be only rotating the spatial axes. OK, your model is a 3D one, so talk of worldlines and such is perhaps speaking to a different interpretation, but you did it in your web page. In the one diagram for question 2, the worldline of the planet (you drew the worldlines of all 4 objects) that moves to the right was depicted as parallel to the time axis, but in the simulation of the same scenario, the temporal axis was oriented with the left-bound planet. You rotated the temporal axis to be parallel to the worldline of a different planet. The speed of each object were suddenly not exactly the same, since a different planet is now stationary, and the former stationary planet is now moving at .866c to the right.
Frames of reference are always 3D Newtonian representations, and to switch to a genuinely different frame, the origin must be moving relative to the first frame.
Frames don't have positions or origins. They don't have velocities, but they do have velocities relative to each other.
Frames move relative to each other just as objects which are at rest in different frames move relative to each other.
Yes.
As for why they have such a pathological hatred of LET, that has always been an unfathomable mystery to me.
I don't hate it. It isn't wrong. It doesn't contradict relativity. It just isn't the only valid interpretation, and you seem to feel otherwise.
You're standing at point A and you know that an event will happen at a certain time at point B. One frame of reference tells you it must have happened by now, but another frame tells you that it hasn't happened yet.
If I am at the spatial location B where the event happens, then the fact that the event has 'happened by now' or not will not be dependent on frame. I presume that point A is not at B. From any other location in space such as A, different frames order events differently, and the event at B may be in the future or past of some event at A. Again, this would violate the law of non-contradiction only if the A before B and B before A were true in the same way, but they're not since they're being considered in different frames. You presume that there is an objective ordering of events, which is not asserted (or denied) by relativity. I think LET asserts such an ordering, in which case the one frame is preferred, and the other frames order events incorrectly. SR just says there is no local way to know if B has happened before A.
If both frames are equally valid, then both are equally true: the event has already happened AND hasn't happened yet.
No. The event has already happened in one frame, AND hasn't happened yet in another. Relativity does not use your wording.
That is a very stark contradiction, and if you can't see that it's a contradiction, you're beyond help.
You presume an objective ordering, and if you chose one, then you can happily say that other frames order events in non-objective order. SR does not forbid this. Relative simultaneity is not the same as objective simultaneity, and SR only speaks to the former. I am stationary in my chair here, and at the same time am moving at 1000 km/hr due to spin of Earth. This is not a contradiction in the same way that your example is non-contradictory.
That's because it's ignored, but it logically depends on it regardless.
How can it be logically dependent on what it doesn't mention? As I said, it only has one premise, and that premise doesn't mention a fabric or an objective frame. It seems you need to assert such things to beg your specific interpretation, but SR doesn't assert any particular interpretation.
The only alternative is that everything has to carry some kind of data to give it a location through a system like coordinates and they have to crunch lots of data in order to work out if they're supposed to interact with each other - that would be a virtual universe rather than a real one.
Things have a location???? I'd love to know the location of us, without relating to anything else that has no more of a location than us. From the big bang (the only objective event I can think of), how would you direct somebody to this galaxy? That at least gives an origin. What are our coordinates from there?
Less time still passes on Earth in the frame of a ship making a rapid trip from here to some distant star. Fabric of space (or lack of it) makes no difference to that.
If you don't have a space fabric, how do you support the phenomenon of distance in order for the ship and the "distant" star not to be touching each other from the start?
You're confusing space with objective space. Things still have relative separation under SR, just no objective location or objective velocity. The fabric is the objective aether-like stuff in relation to which one might be objectively stationary.
So you continue to assert, yet very accurate measurements in different frames confirm this fact that you find so contradictory. Constant light speed is the sole premise of SR in fact. The rest follows from it.
Different frames set the speed of light relative to them to c as part of the rules as to how frames work, and that dictates everything else they do - they do not confirm the speed of light relative to themselves because they have set themselves up directly on the basis that light travels at c relative to them, and in doing so, they all assert that the speed of light relative to ALL other frames is >c in some directions and <c the other way.
Ouch...
Is this a deliberate misrepresentation? This is in direct conflict with the empirical premise of SR. It describes no known theory, LET included.
No - they are radically different theories (using very different mechanisms) which happen to share the same maths and make the same predictions.
Sharing the same maths sounds like the same mechanisms. Sharing the same predictions sounds like the same theory, but differing on being grounded on a preferred frame. I looked it up, and while it had different roots, the modern version is just considered to be just an interpretation of SR with a preferred frame playing the role of the otherwise undetectable aether. The distinctions with standard spacetime interpretation of SR are all just philosophical, not scientific.
That's fine, but it isn't a different scientific theory then, just a different metaphysical interpretation of it. SR doesn't assert any particular interpretation. ... Maybe you think relativity asserts a certain philosophical interpretation, but it doesn't.
SR dictates that there is no absolute frame; that no frame is superior to any other
It says there is no local test to detect it. It doesn't assert its nonexistence. In fact, an obvious one is suggested by a non-local test: the frame of the center of gravity of all the stuff within sight.
SR produces contradictions because its dogma produces them. LET does not produce those contradictions because it recognises that at any location, one frame represents reality correctly and all the rest misrepresent it.
SR is not a metaphysical model of reality. It is a scientific theory that states that local empirical observations of any test will behave the same in any frame. You seem to confuse this scientific theory with the metaphysical model that there is no objectively more correct reference frame. That metaphysical model does indeed sometimes accompany the SR theory, but SR does not assert it. GR sort of asserts a preferred frame, so in that sense, GR and LET are quite similar.
How can two theories make all the same predictions, but one has contradictions? The contradictions are probably because you are begging the premises of the LET interpretation and applying those premises to an interpretation that is not LET.
One theory says that "it's already happened" and "it hasn't happened yet" and simultaneously compatible claims, but the other says they are contradictions.
SR does not claim "it already happened". It claims that it it already happened in a certain frame, which is a relative simultaneity, not an absolute (metaphysical) one. SR does not assert what is. It just asserts what will be measured. The former is metaphysics and the latter is science. You seem to have no capability to separate the two.
For instance, SR does not require 4D spacetime to work. I've defended that fact in some topics where the OP claims that relativity proves or asserts 4D spacetime. It doesn't. The 4D model just simplifies the mathematics, but any frame at all can be designated as the preferred frame, and the whole thing still works. Events are then objectively ordered, and frames that order them otherwise are simply not the preferred frame, but those frames are not 'incorrect' because of that.
Einstein's original SR without 4D Spacetime produces contradictions.
Oh really...
Seems to work fine in 3D. It is instructive to do the standard train/platform example in 3D instead of 4D.
As for LET describing a 'flow of time', constant or not, there is no way to detect a flow (or lack of it) at all. There is not even a unit for it. Seconds per second? That simplifies to nothing, like asserting that distance flows at a rate of meters per meter.
Time is locked firmly to causality at every step. Causation is a process with befores and afters running all through it and it has to flow through in order.
Funny, but I can effortlessly find a causal structure that has no flow. I don't care to argue eternalism with you. Relativity doesn't assert it, so I'm fine with your biases for the topic at hand.
OK, the thread is sort of about it, and not about relativity. The arrow of time is proved by entropy. Without that, there is no arrow. Past and future are not distinct.