# Length contraction is EM forces (split from Lorentz-contraction)

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md65536;

A measures the length of objects by recording the time of reflected light signals as they pass.

In the top view, initial conditions are m1 and m2 at rest in the A frame. Each is 1 unit in length and 1 unit apart.

In the middle view, m1 and m2 are moving at .6 toward A. A measures their length as .8 units.

In the bottom view, A is moving at .6, past m1 and m2, but assumes a pseudo rest frame, with m1 and m2 moving past him. A measures the lengths and the separation as .8 unit.

The measurements of the middle view differ from those of the bottom view.

Length contraction is a change in the em forces that bond molecules. This phenomenon is observed in objects with a motion relative to the observer.

In the middle view, only the objects are lc. The space between has no material composition, thus no bonds. The objects are independent of each other, and not a composite object.

The issue of space between objects does not occur in the typical two system comparison, such as K and K'.

A's time standard changes from 1 unit to .8 unit.

A's motion alters his perception of time, which alters his measurements of distance.

Two examples may help clarify the role of perception in Relativity.

In the train scenario, the passenger drops an object, which falls vertically to the floor.

The bystander on the platform observes the object fall in a curve to the floor.

Does the object follow multiple trajectories simultaneously? Yes, if the trajectories are perceptions. No one sees planetary orbits, they are inferred by plotting positions over time.

In the GR elevator example, the person in the box observes the light to follow a curve from one side to the other, while he senses an acceleration on his feet. If he is truly being propelled upward, then it is his motion that produces the curve, and thus his perception, since anyone outside the box at rest would observe a straight line path.

Transforming this case to a person standing on the ground with an equal gravitational acceleration, light should follow a curve.

Another comparison.

In the sun centered system, the motion of the planets is primarily regulated by the sun, without human observation.

In the earth centered system, the more complex motion of the planets requires additional forces/explanations to account for retrograde motion, to match human perception.

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9 hours ago, phyti said:

Length contraction is a change in the em forces that bond molecules.

No, it’s a relationship between reference frames in spacetime, same as time dilation. All inertial frames are subject to the same laws of physics, so there are no changes in any of the fundamental interactions. Specifically, and quantum mechanics aside for the moment, EM forces can be considered as 4-vectors, which are invariant under Lorentz transformations, so all observers agree on them. What observers do not necessarily agree on, however, are the precise numerical values for each component of that 4-vector.

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20 hours ago, phyti said:

Length contraction is a change in the em forces that bond molecules. This phenomenon is observed in objects with a motion relative to the observer.

That can't possibly be the case. How can there be a change in EM force caused by an observer? How can there be a different change in my body depending on whether my speed is compared to a meteorite or a neutrino.

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forum;
I am not using the 4D mathematical representation theory of Minkowski.
This is interpreting SR in terms of mass, energy, light and motion, as in Einstein's original development, with emphasis on perception by the observer. Perception involves biological processes, which is chemistry, which is physics of the electron cloud.

In view a, a light clock at rest relative to observer Al, with a photon motion from emitter/detector ED to mirror M for a half cycle.
In view b, the clock in motion to the right relative to Al. The photon energy can be resolved into a horizontal component vt that compensates for the clock motion, and a vertical component ut that becomes the active part of the clock. For the clock moving at .5c, the cycle rate is .87 the rate of the static clock.
In view c, the perception of the clock by the observer moving with the clock.
With additional oscillation in the x direction, this becomes the MM experiment.

With electrons replacing the mirrors, it explains length contraction. Longer times between photon interactions is equivalent to greater distances. Length contraction is another manifestation of time dilation.

forum;

An observers motion does not cause changes in distant processes. It can only alter the perception of the observer and his measurements.

Action at a distance was abandoned with Relativity.

Here are a few papers that support a physical length contraction.

Edited by phyti

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1 hour ago, phyti said:

An observers motion does not cause changes in distant processes. It can only alter the perception of the observer and his measurements.

False dichotomy.

Time and distance are relative rather than absolute. i.e. it’s not merely perception of the observer. It’s what the observer will measure. And there is nothing wrong with their instruments.

On 8/23/2020 at 4:36 PM, phyti said:

Length contraction is a change in the em forces that bond molecules. This phenomenon is observed in objects with a motion relative to the observer.

If I am moving relative to some markers in space, the distance between them will be length contracted. There are no bonds, no EM forces that could be contracting, in that empty space.

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This comment of mine belongs here

On 8/23/2020 at 9:36 PM, phyti said:

Length contraction is a change in the em forces that bond molecules. This phenomenon is observed in objects with a motion relative to the observer.

In the middle view, only the objects are lc. The space between has no material composition, thus no bonds. The objects are independent of each other, and not a composite object.

The issue of space between objects does not occur in the typical two system comparison, such as K and K'.

Relativity is taken into account into modern treatments of bonding, starting with Dirac's equation.

But, considered as speeding point charges and masses, electrons are not moving fast enough for the drastic and dramatic scenerios postulated by winterlong.

Splitting a thead is usually difficult, but well done swansont.

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2 hours ago, phyti said:

Here are a few papers that support a physical length contraction.

These are not "papers" in any meaningful sense.

On 8/23/2020 at 9:36 PM, phyti said:

Length contraction is a change in the em forces that bond molecules.

Explain how those forces can have multiple different values at the same time.

1 hour ago, swansont said:

If I am moving relative to some markers in space, the distance between them will be length contracted. There are no bonds, no EM forces that could be contracting, in that empty space.

And, at the other extreme, we know (from observation) that protons are flatted by their relative motion in an accelerator but EM forces do not play a significant role.

2 hours ago, phyti said:

This is interpreting SR in terms of mass, energy, light and motion

In other words: wrongly.

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17 hours ago, phyti said:

Here are a few papers that support a physical length contraction.

Those are not ‘papers’, and length contraction is not a process of physical changes; it’s a relationship between frames in spacetime, as explained earlier.

17 hours ago, phyti said:

I am not using the 4D mathematical representation theory of Minkowski.

It’s nothing to do with anyone’s theories, it is just standard differential geometry - which is something you should be using when you talk about spacetime, because then misconceptions like this one won’t happen in the first place.

Edited by Markus Hanke

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simultaneity and length contraction required for reciprocity

SR requires both ends of an object be located simultaneously.

A is black, B is green, each ship is length d, g=gamma.

The near end of both ships are at 0 for all measurements.

left:

A measures location of far end of his ship at d, on his axis of simultaneity Ax.

A measures location of far end of green ship at d, on his axis of simultaneity Ax.

B ship length/A ship length =1.

B measures location of far end of his ship at f, on his axis of simultaneity Bx.

B measures location of far end of black ship at e, on his axis of simultaneity Bx.

A ship length/B ship length =1/g^2.

Measurements are not reciprocal.

right (with length contraction):

A measures location of far end of his ship at d, on his axis of simultaneity Ax.

A measures location of far end of green ship at d/g, on his axis of simultaneity Ax.

B ship length/A ship length =1/g.

B measures location of far end of his ship at f, on his axis of simultaneity Bx.

B measures location of far end of black ship at e, on his axis of simultaneity Bx.

A ship length/B ship length =1/g.Measurements are reciprocal

Edited by phyti

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5 minutes ago, phyti said:

SR requires both ends of an object be located simultaneously.

Located where simultaneously?

And simultaneous according to who?

6 minutes ago, phyti said:

The near end of both ships are at 0 for all measurements.

At 0 in which frame of reference?

7 minutes ago, phyti said:

left:

What is "left"? Is it the same as A or green, or is it something else completely?

7 minutes ago, phyti said:

A measures location of far end of his ship at d, on his axis of simultaneity Ax.

What is an "axis of simultaneity"?

8 minutes ago, phyti said:

A measures location of far end of green ship at d, on his axis of simultaneity Ax.

Only if they are both stationary relative to one another.

(Not sure what you had to make things so complicated by using A and black, and B and green (and left and right?) to refer to the same things.)

10 minutes ago, phyti said:

B measures location of far end of his ship at f, on his axis of simultaneity Bx.

What is 'f'?

Why isn't the length of his ship d in his frame of reference?

Quote

B measures location of far end of black ship at e, on his axis of simultaneity Bx.

What is 'e' ?

11 minutes ago, phyti said:

A ship length/B ship length =1/g^2.

What is 'g'?

You are saying that g2 = f /e ? (Or maybe g2 = f /e? I am confused by your constantly changing names for things)

How did you calculate this?

13 minutes ago, phyti said:

Measurements are not reciprocal.

What does this mean? (It sounds wrong, but unless you explain it, it is hard to know.)

I'll ignore the rest, because without some explanation, I have no idea what you are trying to say. However, almost every statement appears to be incorrect.

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On ‎8‎/‎24‎/‎2020 at 2:34 AM, Markus Hanke said:

it’s a relationship between reference frames in spacetime, same as time dilation.

This is the accepted view.

On ‎8‎/‎25‎/‎2020 at 1:27 PM, phyti said:

This is interpreting SR in terms of mass, energy, light and motion,

This is not.
Because energy , motion, light ( frequency/wavelength ), and relativistic mass ( variant ) are all frame dependent !

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On 8/25/2020 at 1:27 PM, phyti said:

forum;
I am not using the 4D mathematical representation theory of Minkowski.
This is interpreting SR in terms of mass, energy, light and motion, as in Einstein's original development, with emphasis on perception by the observer. Perception involves biological processes, which is chemistry, which is physics of the electron cloud.

"Perception of the observer" to include biological processes is NOT physics. Generally we strive to remove the human from the process when biological processes will skew the results.

The "perception of the viewer" that matters in relativity is the relativity part —that (as MigL notes above) the observation of motion and measurements of energy, momentum, etc. will depend on the frame from which they are observed. This is idealized - there is the assumption that any bias or error from biological processes has been corrected for.

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I was ending my 14 yr forum participation this year, which began in an effort to answer why Special Relativity was still debated 100 yr after publication, and volumes of experimental verification.
Just passing through to see if anything changed.
No change.

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I guess it shows there is no topic that is so solidly accepted that someone won't debate it with some poorly-informed objection. People debate evolution, too, and that's even older.

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