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The Underlying Problem With Some Science Is Interpretation.

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#222 sluggo

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Posted 06 February 2017 - 01:54 PM

OceanBreeze

that is the way the Universe works!

The physics of vector equations, in four dimensions will get to the heart of ‘Einsteinian’ physics, the real physics, the relativistic correct physics.

 

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No, that is the way the theory works! If we understood how the universe works, there would be no need for theories!

The 4D interpretation is due to Minkowski, not Einstein.

'The Meaning of Relativity', Albert Einstein, 1956:

page 1.

"The experiences of an individual appear to us arranged in a series of events; in this series the single events which we remember appear to be ordered according to the criteria of "earlier" and "later", which cannot be analysed further. There exists, therefore, for the individual, an I-time, or subjective time."

page 31.

"The non-divisibility of the four-dimensional continuum of events does not at all, however, involve the equivalence of the space coordinates with the time coordinate."

page 32.

"Finally, with Minkowski, we introduce in place of the real time co-ordinate l=ct, the imaginary time co-ordinate..."

page 31.

I previously cited references to relative light speeds in the SR theory.

The light clock is a simple example of relative light speed <c. If it wasn't there would be no time dilation and light speed would add as vectors just as object speeds do.

 

In the train example, the observer A moving at train speed v measures the relative walking speed u of the passenger B. Since A is in motion u will be too large resulting from the clock sync convention (assigning the time of reflection). That requires a correction via the composition formula.

The light transit time from A to B is independent of A speed but depends on B speed.

The light transit time from B to A is independent of B speed but depends on A speed.

The formula is therefore reciprocal and each measures the same speed for the other.


Edited by sluggo, 06 February 2017 - 01:58 PM.


#223 sluggo

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Posted 06 February 2017 - 01:55 PM

A-wal #209

If what you were claiming was true then the light would have to increase it's speed relative to Observer A so that it passes Observer B at 1c from Observer A's frame of reference, meaning that the speed of light wouldn't be constant.

 

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This is a common source of confusion, especially for newbies, that the light adjusts itself to conform to different observer's expectations as predicted by theory. Clarification requires the difference between the propagation speed in space and the measured speed of light. The first is constant and independent of the source and the observer. The second is constant and depends on the observer's perception which is altered by motion. The light does not change but the observer's perception does.


Edited by sluggo, 06 February 2017 - 01:57 PM.


#224 sluggo

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Posted 06 February 2017 - 01:56 PM

speed:

1.  rate of movement or happening: the rate at which something moves, happens, or functions 

2.  rapidity: fast movement, progress, or operation 

3.  rate of movement irrespective of direction: It is equal either to distance traveled divided by travel time, or to rate of change of distance with respect to time

 

To calculate the speed of an object A relative to an observer M, requires two distance and time measurements which provide Dx/Dt = a. If A and M have a common initial position, then only one measurement is required. Per definition 3 and the above ratio a, a  scalar, the speed of A is has the same dimensions and value as the separation speed. Add a second object B moving at speed b in the opposite direction relative to M. M calculates the separation speed s of A relative to B as s = (a-(-B)) = a+b. If a=b then s= 2a. If A and B are moving in the same direction then s=(a-B) = 0. There are no contradictions of any rules of physics so far.

If these phenomena are examined within the regulations of SR, a limit is placed on object speeds such that a and b are less than light speed , c. This limits separation speed s to less than 2c. Since distance and speed are relations of objects, and not properties of objects, there is no violation of SR theory. 



#225 sluggo

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Posted 06 February 2017 - 01:57 PM

A-wal #216

If only time dilation or only length contraction occurred then it would be a linear progression so that at 0.25c an object would be either 75% of it's proper length or moving through time at 75% of its proper rate from the perspective of the other observer. Because both occur and velocity is distance over time it means that the amount of time dilation and length contraction that actually occurs is the square root of what either would be on their own, so at higher relative velocities the same amount of acceleration cause a greater increase in time dilation and length contraction and therefore a smaller velocity than it does at lower velocities and time dilation and length contraction approach infinity as the speed of light is approached.

 

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Time dilation and length contraction are both motion induced phenomena, i.e. light chasing a moving target. They occur together and the gamma factor that modifies time and length has an  exponential form.

Contrary to the metaphorical interpretation of moving through time, it's just a figure of speech.

In the light clock, light moves in 2 dimensional space. The observer and his clock are moving along the x axis, a one dimensional space.

You can approach the speed of light but you can't approach infinity. It's a contradiction of terms.



#226 A-wal

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Posted 11 February 2017 - 06:28 AM

Yeah, still horribly wrong.

 

You can start by finding references to support all of your assertions in RED.

 

I will just repeat what I wrote above, although I know it has no chance of sinking in to you thick skull:

The parts in red are these...

"...each is subject to the velocity addition formula with regards to their velocities relative to the observer but NOT their velocities relative to each other from the perspective of the observer."

"Time dilation and length contraction are already taken into account with regards to A and B's velocity relative to the initial observer so you don't apply it again to their velocity relative to each other in the frame of reference of that observer."

"...if light is moving a c relative to an inertial observer then in that frame of reference it can't possibly be moving a c relative to an object that's in motion relative to that observer."


If a object (B ) moves away from the observer (A) at 0.5c then light is moving at 0.5c away from that object from the perspective of A, not at c.

From A's perspective:
                                                0.5c
                    Observer--------------------------------->Object
Light-------------------------------------------------------------------------->
                           1c                                                 0.5c

In A's frame of reference B is moving away at half the speed of light so the light moves past B at half the speed of light in A's frame of reference. In B's frame of reference the light passes B at c.


If two objects (B & C) are both moving away from the observer (A) at 0.6 in opposite directions then they are moving away from each other at 1.2c from the perspective of A, not at 0.882353c.

From A's perspective:
                         0.6c                                                      0.6c
A<----------------------------------------Observer--------------------------------->B
A<------------------------------------------------------------------------------------->B
                                                          1.2c

In A's frame of reference B and C are both moving away in opposite directions at 0.6c so they're moving away from each other at 1.2c in A's frame of reference. In B or C's frame of reference they are moving away from each other at 0.882353c.


You're trying to incorporate the consistency of the speed of light and velocity addition formula into one frame of reference. This is a complete misunderstanding of the most basic aspect of SR. You've had this explained to you multiple times in multiple ways and you think I'm the thick one?

 

 

1) the rules for adding up relative velocities change in special relativity. In "common-sense" physics (ie. the realm that we're used to deal with), if the bus is moving at speed v and a person in it is moving at speed u relative to the bus (and in the same direction) then the persons speed relative to the ground is just w = u+v.

This is called the Galillean transformation. In the theory of special relativity though, the speed relative to the ground becomes w = (u + v)/(u*v/c*c + 1)

 

(now a Lorenztian transformation) so you can see that even if u=c and v=c then w = c! You can't go faster than c relative to anything! Source here.

The velocity addition formula doesn't apply to objects that are in motion relative to each other in the frame of reference of a separate observer. If one object is moving away from an observer at 0.6c and another object is moving away from the same observer at 0.6c in the opposite direction then those objects are moving away from each other at 1.2c in the observer's frame of reference. You apply the velocity addition formula from SR if you want to get the velocity of the objects relative to each other in the reference frame of one of those objects.

 

2) One of the basic postulates of special relativity: The speed of light in a vacuum is the same for all observers drifting through gravity-free space (more precisely: for all inertial observers. In particular, its value its independent of an observer's motion relative to the source of the light. Source here.

 

3) Essentially, then, the Special Theory of Relativity can be boiled down to its two main postulates: firstly, that physical laws have the same mathematical form when expressed in any inertial system (so that all motion, and the forces that result from it, is relative); and secondly that the speed of light is independent of the motion of its source and of the observer, and so it is NOT relative to anything else and will always have the same value when measured by observers moving with constant velocity with respect to each other. Source here

The speed of light is always the same relative to an inertial observer, but it will always be something other than c relative to objects that are in motion relative to an observer. If you switch to the frame of reference of one of those objects then light will move at c relative to them but won't be moving at relative to the initial observer in this reference frame. The speed of light is constant in the sense that it's always the same relative to every inertial observer, not in the sense that it's the same relative to every object regardless of their velocity relative to the observer because that would make zero sense.


I'll read the rest later, this is just winding me up.


Edited by A-wal, 11 February 2017 - 06:29 AM.