phyti

19 hours ago, Strange said:

That is not exactly relevant, though, is it.

And what is the source of this document?

As Supernerd, why do you ask, you should know.

Did you find an error in the paper?

On 9/19/2017 at 6:59 PM, thomas reid said:

In Relativity when something is moving does it become actually physically shorter or does it only appear shorter in the rest frame?

Chemistry teaches us that matter exists in lumps and can be deformed. Measure a metal rod, heat it and remeasure it. There are no rigid objects.

The attached file explains why length contraction is necessary to resolve the MMX. 

reflecting circle.pdf

There is still nothing here to discus.

You are right, there is nothing to discuss here. From the feedback; lacking clarity and too much detail.

In the real world, how long does it take to write/generate the unbounded finite sequence 1,2,3,4,5,[...]?

([...] represents the numbers I didn't have time to write)

 

It's impractical to continue up to even the number of electrons in the observable universe

(or some finite number you choose) and you will never reach infinity as each successive number is finite.

 

Much of mathematics is shorthand for something impractical or impossible to work out with basic arithmetic using pencil and paper..

 

If you think the above math is ok, what is the problem with being unable to write every term in an infinite sequence?

 

[crossposted with Strange]

You gave the correct word (red). The ellipsis was invented for just that reason. Since there is no largest integer, no one can write it. Sequences are not laid down instantaneously, so it's a real question as to how long to form one that has no end. .

No, an infinite sequence is NEVER a node in the tree. It's obvious that any node in the tree represents a FINITE sequence.

 

An infinite sequence is a PATH through the tree, and not a node. If you don't see this you don't understand the infinite binary tree.

No, an infinite sequence is NEVER a node in the tree. It's obvious that any node in the tree represents a FINITE sequence.

 

An infinite sequence is a PATH through the tree, and not a node. If you don't see this you don't understand the infinite binary tree.

If you read below the tree, it says each sequence corresponds to a unique path.

So no comment on what you think time has to do with Cantor's argument?

In the real world, how long would it take him to write any infinite sequence?

Given 0 precedes 1, the tree begins with a repeating zero and ends with a repeating 1, so all sequences will be included between those two.

How can p (green) be in the tree, when Cantor says it isn't in L?

Phyti, I found a couple of problems in your paper.

 

1) Your tree does not contain all binary sequences. For example, what node of the tree contains the sequence 101010101..., that is, alternating 1's and 0s'? The solution is that real numbers are represented as paths in the infinite binary tree, not nodes. Although there are only countably many nodes in the tree, there are uncountably many paths.

 

2) You wrote: "For large values of k the "end" of the list effectively accelerates into the future ..."

 

This of course is incoherent. Does the sequence of natural numbers 1, 2, 3, ... "accelerate into the future?" This is simply meaningless.

You begin at L, toss a coin, which selects 0 or 1, move 1 segment/branch, repeat...

The choice is always the same, and it's always from L! Repeating 10101... would continue along the lower portion of the tree.

The acceleration is just a description for his task, he has more to change than what he has changed.

Cantor's list has no end, thus he can't reach it by any means, just as he can't write the greatest integer.

I'm just using HIS method to show where it doesn't lead.

The paper has been revised many times, and the one linked was not the latest. After reducing it to the bare essentials, it's up for criticism. https://drive.google.com/file/d/0ByCTeSH4WyfPSXRtdUR6OC04RjQ/view?usp=sharing

https://drive.google.com/file/d/0ByCTeSH4WyfPTWtMWEtGQjVPQ3c/view?usp=sharing

 

Don't be rdiculous.

wikipedia

tests of special relativity

time dilation and length contraction

Direct confirmation of length contraction is hard to achieve in practice since the dimensions of the observed particles are vanishingly small. However, there are indirect confirmations; for example, the behavior of colliding heavy ions can only be explained if their increased density due to Lorentz contraction is considered. Contraction also leads to an increase of the intensity of the Coulomb field perpendicular to the direction of motion, whose effects already have been observed. Consequently, both time dilation and length contraction must be considered when conducting experiments in particle accelerators.

Some say Length Contraction is not physical others do, so at the moment why do you need length contraction, and besides when was the synchronization was done? Some say before others say after the train accelerated.

Am I allowed to say I think you misunderstood me? We now have multiple observers and multiple clocks, all the clocks on the moving train read the same time, and all the clocks on the platform have the same time. So if the center points both agree it is 12:00 each opposing clock set should be agreeing with each other.

 

I understand no one will agree as to the time of a particular event, but we are NOT describing the event, but just saying the opposing clocks will all agree at 1 time only and thereafter won't agree any more.

In the M frame, the train is moving to the right, with the viewer T at center, and B and F back and front emitter/detectors. B and F emit simultaneous signals in the M frame, which are simultaneous with the ends of the train, but will not arrive simultaneously for T.

In the process of accelerating to a constant speed, the T frame has an altered symmetry. If T polls the F and B clocks, B’ and F’, they show different values. This is a consequence of light propagation speed being constant in space. If T synchs the clocks to his center clock, according to the SR convention, then he has “relative simultaneity”, and perceives B’ and F’ as simultaneous. Notice the path lengths are equal, but out of synch, depending on their origin. Simultaneity is a function of speed, not a property of the frame.

The hyperbola is a constant time t=1, wherever it intersects the path of a moving object. In the A frame (black) light requires 1 unit of time to reflect from the end of a stick .5 units long. If the same measurement is expected in the B frame (red), the same stick requires a physical length contraction.

The space between 2 sticks in tandem would increase, not contract. The volume of space remains unchanged.

It's a question of simultaneity. Maybe I wasn't clear in #14.

The clocks are synchronized in the ship/train at rest, which is equivalent to ground time.

When the ship is moving relative to the ground, its axis of simultaneity is skewed (at an angle in a spacetime graphic).

If the viewer on the ship polls the end clocks with light, the clocks will return different readings. Per SR the viewer must establish a relative synchronization of of the end clocks using light signals. The procedure is described in the beginning of the 1905 paper.

The end clocks are synchronized to the center clock while the ship*is at rest. When the ship reaches high speed, the axis of simultaneity is different from the ground aos. The signals will not arrive at the center simultaneously.

If the end clocks are synchronized upon reaching the target speed, then they will emit signals at a preset time, and arrive simultaneously.

1. The objects are independent of each other.

2. If they moved at different speeds, that would require space to contract at two different rates simultaneously!

3. There is no known substance to space that can contract.

4. The contraction involves em fields.

5. The solution to the Bell spaceship problem is decided on the basis of the gap increasing as the ships contract, which stresses the connecting "rope".

6. The separation of the objects contracting along with the objects would be perceived by a viewer moving past them at high speed.

7. In the launch frame U, assume the objects contract from the front, while the back ends maintain a constant separation. The gap increases. To maintain a constant gap, the rear object would have to increase speed, or the front object would have to decrease speed. I.e. they could not follow the same speed profile.

My question is do you think length contraction really happens? What I see in the YT clip is that time is dilated and the ship goes further in dilated second .

Could length contraction be better explained better by showing differing relative speeds rather than than saying the distance to a star is altered by relativistic speeds?

The perception of an observer on earth: muons are created at (x,t)=(0, 0), and move at .9c until decaying at ground level at (x, t). Time dilation slows the muon clock to read t' at x.

The perception of an observer moving with the muons: the ground arrives at t', and x'=x(t'/t). Thus the ground is literally closer, as if the universe contracted in the direction of motion. Knowing that the muon motion cannot alter the dimensions of the universe, the effect is from the altered perception of the observer via time dilation.

He cannot fault his clock or his biological sense of time, and concludes the universe has contracted as it passes him. This satisfies the reciprocity of the principal of relativity.

It's my understanding that when something is going near the speed of light in reference to an observer, time dilation occurs and time goes slower for that fast-moving object. However, when that object goes back to "rest", it has genuinely aged compared to the observer. It's not like time goes slow for a while, and then speeds back to "normal," so that the age of the observer once again matches the object. The time dilation is permanent. Why wouldn't the same thing happen with length contraction? Since the two are so related, you'd think if one is permanent, the other would be also. And from everything I've read so far, length contraction is not permanent. An object will be at rest touching an observer, go far away near light speed, return to touching the observer, and be the same length it was at the beginning. It shortens, and then grows long again, as if its shrinkage was an illusion the whole time. Did I just not read the right things or what? Were my facts gathered incorrectly?

1. A clock produces, counts, and accumulates ticks (an arbitrary interval of activity). If clock A separates from an identical clock B, and later rejoins B, it will have ticked less. While in relative motion, each will appear to run slower than the other, via doppler effects, since clocks can be treated as frequencies. This supports the principle of relativity, in that observations are reciprocal, thus observers with the clocks see the same physical phenomenon. Because light speed is constant, any device requiring light interactions will occur slower, the faster the device moves relative to light. Since all objects are in motion, all clocks are losing time to various degrees. Any age difference between A and B requires a comparison of both at the same location before and after the excursion by A. In the simplest case, the one that changes speed to rejoin, will have aged less for the excursion. In SR there is no speed whereby the clock can regain lost time. If A rejoins B, its rate will change to match that of B.

2. Length contraction occurs when object motion affects the em fields that determine the separation of particles. This also results from constant light speed, and the calculations involve the same function of speed, the gamma factor, as used for time dilation. When the object slows to its original speed it regains the original length, i.e. it doesn't loose length.

The Minkowski drawings can be misleading. The space time interval is s^2=x^2-(c^2t^2) For c the interval would be 0. The traveling twin had a shorter interval. In the Minkowski diagram the twin on earth would appear to have the shorter world line. The straight world line is actually the longer line. The traveling twin would have a shorter world line between the start of the journey and the end. Michael describes the world line as a train track and the particle as a train. The end of the journey is where the tracks intersect. If both trains are traveling at the same speed then they should not meet at the intersection at the same meta time. The traveling twins path is shorter.

It’s misleading when misinterpreted as a 2D roadmap, and viewing the longer world line as the x=vt relation, when it should be the t=x/v (inverse) relation. Even without relativistic effects, and all other factors equal, the faster clock will reach the target showing LESS time.

Can you demonstrate that if they both traveled along their world lines at the same speed they would meet up. This would be according to Michaels claims. They would vacate previous positions and not occupy future positions. Is their world lines the same length from the beginning of the journey until the end?

If they separate and later rejoin, both could not have maintained the same speed for the trip.If you use a Minkowski drawing, which shows the speed profile or history of each, it demonstrates why the shape of each profile determines the elapsed time.

What is the lowest speed you can travel to go 200 years into the future within a 10 year time frame by going in a circle around the earth?

You can't travel into the future. The future is what will happen later. If you want to slow your rate of aging, that's another subject.

What about the cycles?

Yes, but when do you stop asking?

 

 

Is it really not testable, or do we simply not know how to test it yet? If it's truly and absolutely untestable, then there is indeed no point, but can you be sure that these things really are untestable? How do you know what is truly untestable?

Motion is the behavior of multiple objects. It’s observing the change of positions relative to one of the objects selected as a reference. Obviously it is not an object property but a group property.

If an object wanders into the vicinity of Earth, it acquired its velocity at some time in the past, if we accept cause and effect. It could be a relic from planetary formation thousands of light years distant, but we have no way of knowing its history.

Yes, the propagation speed of light in space (ideal vacuum) is constant and independent of its source. It serves as an absolute reference for speed, as in the expression v/c used in SR. If we could set a marker at the spatial location of emission, we would have a fixed point of reference for subsequent calculations. Imagine finding a productive fishing spot and leaving a buoy (no anchor) at the site. The next day you return to the buoy. How do you know it’s the same spot? That’s the problem since light emission leaves no residue for the CSI.

If you analyze the physical phenomena in a moving test frame relative to a theoretical absolute static frame of reference, you discover the phenomena occur as if the test frame is not moving. Fascinating to discover but greatly simplifying analysis and application of rules of science. Eg., NASA can calculate an orbit without knowing the center of mass of our galaxy.

When the phrases time dilation and length contraction are used, what do these really mean?

 

For example, say in the travelling twin paradox, there is a perceived time dilation that both twins observe happening to the other, as the travelling twin sets off (and a perceived time contraction as the twin returns).

 

I understand these meanings - perceived because it is a consequence of the twins moving away from each other, each twin observing the same perceived time dilation as the other.

 

But I have also seen time dilation being used as an actual time dilation - i.e. in the sense of 'rate of time' slowing down - and that I do not understand?

 

If the travelling twin really experienced a slow down in his rate of time, then by what action does his 'rate of time' return back to 'normal'?

 

The explanation that I have been given on this, is that the rate of time (not perceived) never changes for the travelling twin, but rather the distance of the travelling twin's space-time line is shorter than the stay at home twin's space-time line. So the travelling twin's rate of time does not change, but because his space-time line is shorter, his clock has gone through fewer 'ticks'.

 

This look a bit odd on a space-time diagram, as the travelling twin's space-time line looks longer on the diagram.

 

I do not understand space-time diagrams to know if that explanation is valid or not.

Could someone help and explain what a space-time diagram really represents and how this all works.

 

Maybe this will help.

Time dilation and aging for a pair of clocks.doc

 

I'm not sure how that has been concluded from my question?

 

My question was: if two photons are moving side by side, are they in the same reference frame?

 

Or the other way to ask the same question: if two photons are moving side by side, is it possible that they are not in the same reference frame?

 

The reason for wanting the answer agreed to that question, is because of this observation...

 

Two photons moving side by side need not have originated from the same point in space and time. For example, a photon from a star a thousand light years from us, reaches us and as it passes by, we can create a photon such that the two move side by side with each other.

 

So in that situation, assuming the answer to the question above is that they are moving in the same reference frame, what is the connection between how those two photons have been created?

 

So getting back to my opening question: Is it possible that these two photons were created against the same reference frame? And then, since there is nothing special with how those two photons were chosen, does that mean that all photons are created against the same reference frame? i.e. an absolute frame of reference?

Why does the absolute fixed frame keep coming up?

Not because people can’t think. There are many creative minds in the world, but all aren’t interested in physics. It could be because given the fact of constant light speed in space, the inquiring mind expects a constant feature in space itself. If we begin with the obvious, events don’t move, then it’s simple to form a hypothetical fixed frame of events. An analogy would be watching fireflies at night in your yard.

If you are a forming a theory involving light and object motion, you would require such a frame when expressing relative light motion using terms like (c±v). After developing the theory, you find that the moving frames behave like the fixed frame, with respect to the rules of physics. The fixed frame served a purpose, but because it is not observable does not imply it is non existent.

We can't see light in space because there is nothing for light to illuminate. But is there still an electromagnetic wave between the Earth and Sun or does this disturbance happen because of atmosphere?

 

Is space empty, or is space a "sea of photons"?

 

 

Space contains many photons moving in random directions from random sources. Considering the earth intercepts only a small pencil of light from any source, the major portion moves past us. In this sense space is ‘full’ of light.

Questioning what portion of the sun’s radiation is intercepted by the earth, consider the earth a disc projected onto a spherical surface with a radius of 93 million mi. Assuming no errors, if the surface was scaled to the radius of the earth, the disc has the diameter of a nickel. Imagining the amount of heat received on one hemisphere on a cloudless day, the total output of the sun has a high boggle factor.

Don't anthropomorphize nature. She hates that.

Don't forget father time!

Thanks for all responses. I'll have to read suggested sources to learn more.