Quote rom one of your earlier postings. “…so while it is true that there isn’t a preferred frame, there is still a preferred class of frames that informs the universe’s bookkeeping. So which is it then? What is the fundamental reality? Is there some background on which objects are “tracked”, be it the “class of inertial frames” (the Poincare group), or are things really relative? The ultimate problem is that our modern understanding of SR eschew’s the beautiful Machian insights that originally motivated Einstein in the first place. When I first learned about relativity, I had the impression that the principle was so ultimate, that, for instance, if the earth is rotating relative to nothing in an otherwise empty universe, then it really isn’t rotating at all, since there is nothing relative to which it is rotating. But the solution to the twin paradox tells us that the answer is yes: the earth can rotate even if it is relative to nothing. In other words, it’s not all relative.** There is some background against which the universe keeps track of things.**”
I added the bolding. You haven’t called it (them) a preferred frame, but what else is it?
My argument for exceeding the speed of light is not incoherent. You are quite at liberty to disagree with it if you want to, as I am quite at liberty to disagree with Einstein’s theories. I think I may have said this before, but his maths is probably correct. He is incorrect in his application of the maths. The real world can always be represented mathematically, but mathematics does not always represent the real world. In other words, his (or Lorentz’s) formulae, may be mathematically correct, but bear very little relation to the real world.
I’ve called it a Lorentzian manifold. I’ve called it a class of frames. I could also call it a frame bundle (any given frame is a section of a frame bundle). In SR/GR, there is no preferred frame. But there is a preferred class of frames; movement is relative to something that is more general than a frame. This may sound complicated and you may not like it. But I’m sorry, nature is complicated. That’s the way she is. What all this means is that, despite the ostensible equality of inertial frames when viewed in a local context in isolation, the length of timelike curves joining two points has a local maximum for a timelike geodesic: ie a straight line. In other words, the twin that is in free fall will always age most. The twin that accelerates is obviously not in free fall, and will age less. I already linked to the wikipedia page for proper time. This is how you calculate it. You can do it* in any frame*, and you will get the same answer for which twin aged more. That’s the point. For any inertial frame, for the entire class of frames, this holds true: the one that accelerates always ages less. That’s why the relativity of inertial frames holds only for… wait for it… inertial frames.
You are not at liberty to disagree with Einstein’s theories, because they have passed every experimental test, and you have offered none that might falsify it. In particular regarding objects that would, if it not for SR, surpass the speed of light (think particle accelerators, for one). Can you think of a test that would disprove Einstein’s theories? The fact that objects have been observed to not exceed the speed of light, and in such a way that is in exact accordance with the math of relativity, is apparently lost on you.
I’ve noticed discussions of relativity can get very confusing. We’re so used to relying on intuition and instinct. Yet, since we don’t travel around near light speed… humans have neither when it comes to SR.
I pulled together an interactive simulation of relativity that may come in useful here:
It may not answer these quasi-philosophical questions that are being mulled over here, but the simulation should hopefully lend some instinct for SR.
Cheers!
Very nicely done! However (but you may be aware of this), the nitpicker in me can’t resist pointing out a slight inaccuracy, if the picture as depicted is supposed to be what velocity raptor sees: you effectively still assume an infinite (or very high) propagation speed for the light reaching an observer; otherwise, because of the Terrell-Penrose effect, the finite speed of light leads to a visual appearance that’s different from just the observation of Lorentz contraction. Namely, the light from different points of an object arrives at (at these speeds) significantly different times, and in particular, light emitted at some angle from the back of an object may nevertheless reach an observer, because the object ‘moves out of the way’ fast enough. Thus, one actually does not merely observe a contraction, but actually, both a distortion and a rotation as well! In fact, I think circles ought to not appear squashed at all, but merely rotated… But of course, since this effect is purely visual, it would only add unnecessary complications to your game.
(Here’s a visualization of the effect, btw.)
Good eye for that. Those effects come into the game later.
For the first two dozen levels I keep things simple (showing Measured relativity… or assuming that light does make it to you instantly). This allows the player to get a feel for length contraction and time effects.
In level 25, I introduce the finite propagation you mentioned. It bends and curves the world so strangely, that I didn’t want to introduce it right away, lest the players were woefully confused.
At the moment I hope they are just pleasantly confused.
Well, then I guess I have to keep playing! 
I am a democrat. I can disagree with anybody, anybody can disagree with me. I am perfectly at liberty to disagree with Einstein. As for SRT, it may not have been disproved but it has not been proved either.
Your last sentence is seriously misleading, and is what relativatists resort to. The ONLY time that “objects have been observed to not exceed the speed of light” (and note how completely illogical this sentence is; how is it possible to observe something not doing something?), is in a particle accelerator(if you have read my posts you will know what is coming), where the push force is electro magnetic in one FR, and the particle is in another FR. The push force is itself constrained to the speed of light, so how is it possible to push something faster than the speed of the pushing force? If however, the pushing force is a reaction motor (note to a previous objector - a reaction motor produces a force) in the same FR as the object (eg a rocket with its internal rocket motor), there is no theoritical limit to its velocity.
If the speed of light is relative to the observer/detector, then a ring laser cannot work, but it does. Relativists have had to stand on their heads to explain this away, and then not very convincingly, except to themselves of course. Just as Ptolemy had to add epicycles upon epicycles to keep up with observation, relativists have had to do something very similar.
When the GPS was designed, the satellite clocks were synchronised to the ECI, which became the preferred FR, and LET was used, not SRT. This was aired on this forum a short while ago, and I was directed towards a web page which would prove me wrong. It did no such thing, as although it insisted on calling the relativaty corrections Einsteinian, the Earth was still the preferred FR, with all clocks synchronised to it. The speed of light is therefore constant in this frame, and not in the satellites’ frames. In other words LET was used.
Tom Van Flandern “Of critical importance to choosing the model that best represents nature, none of the eleven independent experiments testing SR verify frame reciprocity or distinguish SR from LR. In fact, historically, de Sitter, Sagnac, Michelson, and Ives concluded from their respective experiments that SR was falsified in favor of the Lorentz theory*. Indeed, the GPS itself is a practical realization of Lorentz’s “universal time”, wherein all clocks remain synchronized despite being in many different frames with high relative speeds. However, subsequent re-interpretation of SR allowed that theory to survive these objections.”
I would just like to say that this is I e if the funniest physics threads this forum has had in a long time!
I’m not clear on precisely what you mean by “speed of the pushing force,” but assuming you mean the speed of whatever’s pushing on an object, this isn’t even true in Newtonian physics.
For example, note the wind-powered car that exceeds the speed of the wind (relative to the ground):
I’ve already posted the relevant equation above. The ‘resolution’ is simply that a constant proper acceleration transforms such that in an inertial frame the velocity of the accelerated object asympotically approaches c. This is just a result of the hyperbolic nature of spacetime.
Is this the old Sagnac effect chestnut? Infact due to the construction of ring lasers, I believe you actually need special relativity to fully explain the intereference effects.
You’re misreading what Van Flandern says on his web page. He simply says that LET is a better paradigm for explaining the relatvistic corrections needed in the GPS than SR. However Einstein’s paradigm was used (for little it’s worth as functionally LET and SR are exactly the same). LET wasn’t used simply because no-one who actually does that kind of stuff uses LET, except in the way that using SR is in nearly every way equivalent to using LET (Van Falndern was involved in a small way with the GPS project, but this was not his area of expertise).
I replied to this yesterday, but it has got lost. Here it is again, apologies if it appears twice.
Very interesting video. I like it because I am an aircraft engineer. Let’s take a closer look. Note the shape of the propellor, it has a leading edge which is usually but not always straight, but it is always straighter than the trailing edge which can be quite curved. If the propellor is being turned by the wind, the leading edge faces into the wind. If the prop is motor powered, the leading edge faces forward. Note the orientation of the prop on that vehicle, the leading edge is facing forward.
The wind is blowing from the rear, which hits the prop blades, and the pitch angle causes them to turn. Pitch is the amount of twist in the blades which acts as a screw, and as the prop turns (by a motor), it screws itself into the air, or pulls the air backwards. Looking at the vehicle it can be seen that the near blade, when it is pointing towards the camera, is twisted at about 45 degrees top left to bottom right. The wind hitting this blade would be deflected up, which would push the blade down. This would cause a clockwise rotation of the prop (as seen from the front). Notice the rotation of the prop, it is anticlockwise (as seen from the front).
THE WIND IS NOT CAUSING THIS PROP TO ROTATE, IT IS BEING DRIVEN.
You have been hoaxed Arjuna34.
Did you actually read the other thread? The wind is not causing the prop to rotate, and the cart works and is not a hoax.
Sorry, I forgot that from your IFR, the prop rotates in the correct direction, and has turned itself round so that the leading edge is now pointing into wind. I am sure there is a formula somewhere to prove that.
That is the last I have to say on this ridiculous matter. We have gone way off topic, we are supposed to be discussing relativity here.
If only you’d direct that critical attitude towards your own arguments… But I guess that’s the hardest thing to do. 
But really, a moment’s thought about your ‘rocket with internal motor’-proposal would expose its shortcomings. First of all, if anything can be said to ‘apply’ the force to the rocket, it’d certainly be the reactant, not the motor – which is being expelled, and thus, of course in a different frame of reference. In fact, you can’t accelerate anything using only forces the object acts with on itself – that’s conservation of momentum. Think about an ice skater on a perfectly frictionless surface: there’s nothing he could do to himself in order to make himself move. Only things like, say, throwing a snowball, or anything else that involves imparting an equal but opposite momentum to something else – which would, in your analysis, introduce a second frame of reference --, would allow him to change his state of motion.
But more importantly, the kind of force used to accelerate a rocket or an ice skater, or what it acts on, of course does not matter at all. Only a difference in velocity between two frames of reference is necessary for things like time dilation and length contraction; so no matter how you accelerate your rocket, even if you use magic to somehow bring it up to speed, it will be true that you can’t accelerate it past light speed relatively to any observer. This is just a basic consequence of the empirical datum that the speed of light is equal in all frames of reference. You may fight that observation, but, once you accept it, there’s no way around this consequence.
You could do worse than to play testtubegames’ game above; it does impart some intuition about special relativity, the lack of which seems to be mainly what’s tripping you up. Plus, all the effects are explained in a rather simple and straightforward manner on the ‘relativity 101’-page.
Point 1.
I have directed that critical attitude to my own arguments. At one time I was a believer in SRT, so I had to look to myself and the theory very closely indeed to come to my decision. The shortcomings you mention are there alright, I will point them out to you.
The universe bends itself to my will literally (well, not my will, but certainly my actions) according to Einstein. If I travel at close to the speed of light towards Proxima Centauri, the distance between the Earth and Proxima Centauri is no longer 4 light years, it is 2 light years. This is not a visual effect, it is real.
My brother Tim set off at the same time as I did towards Proxima Centauri in a less powerful rocket, so he travels slower than I do. The distance between the Earth and proxima Centauri is no longer 4 light years, it is 3 light years. This is not a visual effect, it is real.
When professor Dingle pointed out the absurdities in Einstein’s SRT, he referred to clocks only. Perhaps if he had mentioned the above absurdity, he would have had a stronger case.
Point 2.
The rocket’s internal motor is ejecting the reactant as you say, and that reactant, through action and reaction, causes the rocket to move in the opposite direction. The rocket is FR1, and the reactant is FR2. Let us assume that the reactant is leaving the rocket’s nozzle (FR1) at 1000mph, and causing a push of 100 tons. I have no idea if that is anywhere near correct, but it will do. As the rocket accelerates, no matter how fast it goes, the reactant is still leaving the nozzle (FR1) at 1000mph, and still causing a push of 100 tons (on FR1). As long as that push is present, FR1 will continue to accelerate at the same rate with reference to FR2.
Your skater analogy holds. Every time he ejects the reactant (the snowball) he accelerates in the opposite direction. Each snowball gives him exactly the same push. Eventually he will reach a speed very close to that of light. He does not know this of course, as the ice is infinite and homogenous, and neither does the snowball, so each time he throws the snowball he is accelerated by the same amount.
So what’s the problem? You see your brother moving at a certain speed that is less than c. Your brother sees you moving at a certain speed that is less than c. We, back on earth, see both of you moving at speeds that are less than c.
The various relative speeds all fall out of the very simple equation regarding relativistic sums and differences of speeds.
No solution for the equations exists (in real numbers) that provides for anyone seeing anything going faster than c.
Meanwhile, many of these effects have actually been experimentally observed. They did the twin paradox with two clocks, one staying in one place and the other flown around the world.
(They’ve also experimented with two clocks, one staying in one place, and the other lifted, on an elevator, to a higher altitude, thus in a weaker gravitational field.)
Oh, and they’ve built and tested a few dozen nuclear weapons… Alas… On the plus side, I get some of my household electricity from mass-energy equivalence.
not to mention every time an unstable particle is circulated in or produced by, a particle accelerator…
No. Each particle of reactant leaves the nozzle at 1000 mph in FR1 at the moment it is ejected, but since the rocket is accelerating, particles ejected at different times are moving at different speeds relative to each other. These is no “FR2”.
He’s always accelerated by the same amount *relative to the most recent snowball thrown.*However, if you measure his acceleration relative to the first snowball (or to a fixed observer) you’ll notice that his acceleration gets less and less with each snowball thrown.
Yes. Absolutely. That’s how it works. What problem do you have with this?
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