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This is not a trivial question. The answer has significant implications. Time dilation is a definite physical effect and has been confirmed experimentally. It may not be possible to confirm Lorentz contraction in the same way. It is then only via close examination of the mathematics of relativity that an insight can be gained.

QuoteThis is not a trivial question. The answer has significant implications. Time dilation is a definite physical effect and has been confirmed experimentally. It may not be possible to confirm Lorentz contraction in the same way. It is then only via close examination of the mathematics of relativity that an insight can be gained.Exactly! While there is no mechanical reason for contraction there is mathematics that show image contraction.

Quote from: GoC on 14/11/2016 12:19:04QuoteThis is not a trivial question. The answer has significant implications. Time dilation is a definite physical effect and has been confirmed experimentally. It may not be possible to confirm Lorentz contraction in the same way. It is then only via close examination of the mathematics of relativity that an insight can be gained.Exactly! While there is no mechanical reason for contraction there is mathematics that show image contraction.Except that there is mechanical reason for contraction and there is evidence for contraction, i.e., if there was no contraction, one could not have time dilation, since one could not have a consistent theory.

Except that there is mechanical reason for contraction and there is evidence for contraction,

if there was no contraction, one could not have time dilation,

since one could not have a consistent theory.

Which do you understand and why?

However in saying the above, there still exists volume contraction and volumes tend to have a length.

If SR is only a visual effect then GR is the same.

All you have to do is examine how things work under acceleration then apply the equivalence principle.

QuoteIf SR is only a visual effect then GR is the same.Unlikely, Relativity would not work as it does if rods and clocks did not change with dimensional dilation in GR.Quote All you have to do is examine how things work under acceleration then apply the equivalence principle.Equivalence in GR to SR is at a specific point of dilation. You can have 9.8 m/s/s as you approach the speed of light your tick rate continues to slow. But dilation in GR at 9.8 m/s/s has a fixed clock tick rate by dilation of space time specific energy density. Dilation changes the length of rods and clocks as special changes in GR. Geometry shows the image changes in SR with competition between vector mass and light speed. Change the light speed in the Lorentz contraction and the ratio of contraction changes in SR. It is speed of light dependent for contraction Mathematically.

You just said it :"relativity wouldn't work...". That means it is not a visual effectz, it is real.

I think there is a better way to explain this, and you are right, in a way. SR, is pure geometry and only involves time, length and speed and acceleration. GR says gravity is equivalent to acceleration but it is still geometry. All if these explain in fact the reality but at a basic level eve though they are geometric. Then Einstein introduced his equation with tensors still part of GR. These explain things at a level very close to fundamental.So, yes you can say SR is a visual/geometric explanation of reality and so is GR up to the Einstein field equations.

QuoteHowever in saying the above, there still exists volume contraction and volumes tend to have a length.How do we measure volume as relativistic? With the use of light. Now if we understand relativity correctly in SR light is independent of the source. So the reflection and the object are in two different special positions when the image is received by an observer.Two parallel trains at relative rest view each other as perpendicular. Each conductor views the other 90 degrees from the forward vector. There is a unbendable bar between the trains. From the at rest position each train is physically parallel and now traveling half the speed of light. As they approached the half speed of light each conductor viewed the other train as falling behind. The unbendable bar appears to bend towards the trailing train. Why? Because light is independent of the source. The vector of the image between them is no longer 90 degrees from the forward position. It is now 120 degrees from the forward position or 30 degrees behind parallel. The image beyond the train is traveling between the trains. So each conductor views what is behind the opposite train while they are physically parallel. The Doppler effect does the same thing to light images for the perpendicular observer at relative rest. The observer at rest views the object at half the speed of light at a 120 degree angle rather than a 90 degree angle by the time the image reaches him. So the angle of light as the perpendicular position becomes a 30,60,90 geometry triangle. Cos 30 is 0.866025 contracted view. The Lorentz contraction at half the speed of light is 0.866025 which many consider physical contraction just because the image is contracted. Smoke and mirrors can fool most of us. The visual image is just smoke and mirrors.

Quote from: Nilak on 22/11/2016 17:14:20I think there is a better way to explain this, and you are right, in a way. SR, is pure geometry and only involves time, length and speed and acceleration. GR says gravity is equivalent to acceleration but it is still geometry. All if these explain in fact the reality but at a basic level eve though they are geometric. Then Einstein introduced his equation with tensors still part of GR. These explain things at a level very close to fundamental.So, yes you can say SR is a visual/geometric explanation of reality and so is GR up to the Einstein field equations.Special relativity definitely does not include acceleration. That is the whole point of general relativity.

QuoteExcept that there is mechanical reason for contraction and there is evidence for contraction,There is no mechanical reason for contraction in SR.

For proof just change the speed of light in the Lorentz contraction and you will recognize its not a physical contraction. Its just a relativistic relationship to the speed of light.

Quote if there was no contraction, one could not have time dilation, The clock does not contract. With vector speed there is a geometry distance in space That affects the distance light moves relative to c. This distance slows the tick rate of a clock not contraction.

Special relativity definitely does not include acceleration. That is the whole point of general relativity.