[alancalverd]

Well somebody did, because L, T and T/L are not magnitudes.

[jeffreyH (OP)]

Well somebody did, because L, T and T/L are not magnitudes.

They are units. Look at the title of the thread.

[timey]

Someone here should know
Minkowski, in generalizing the time coordinate from t to ict, a 4th dimension, produced a new format for the space-time diagram. Horizontal x, vertical ct. A straight line represents object speed over light speed, vt/ct = v/c = a speed plot. Without the scaling of time by c, a graph would be useless for analyzing motion at fractions of c. Another gain, the issue of the essence of 'time' is eliminated.

...and gravity is also absent from the spacetime diagram, yet experimental tests in reality where there is no escape from gravity show that special relativity is consistent.
This leads me to wondering what it is about special relativity calculations that are incorporating the factor of gravity into the equation.  The fact that special relativity is consistent with experimental data that is gathered in the real world, where there is no getting away from gravity, demands that this be so.
General relativity is a background independent theory, where spacetime  emerges 'from' the calculations, and special relativity is a background dependent theory, where spacetime is a result of a speed as per a percentage of the speed of light held relative to a static length second, when general relativity suggests that the seconds in differing GP are not of static lengths is interesting.
This is why I find some of the remit of DSR (doubly special relativity) to be of interest.

[jeffreyH (OP)]

Think spacetime vector.
https://en.m.wikipedia.org/wiki/Magnitude_(mathematics)

[timey]

That link isn't working for me...

[timey]

Ah - gotcha

Vector (mathematics and physics)
Euclidean vector, used to represent physical quantities that have both magnitude and direction Vector can also have a variety of different meanings depending

[guest4091]

Someone here should know
Minkowski, in generalizing the time coordinate from t to ict, a 4th dimension, produced a new format for the space-time diagram. Horizontal x, vertical ct. A straight line represents object speed over light speed, vt/ct = v/c = a speed plot. Without the scaling of time by c, a graph would be useless for analyzing motion at fractions of c. Another gain, the issue of the essence of 'time' is eliminated.

...and gravity is also absent from the spacetime diagram, yet experimental tests in reality where there is no escape from gravity show that special relativity is consistent.
This leads me to wondering what it is about special relativity calculations that are incorporating the factor of gravity into the equation.  The fact that special relativity is consistent with experimental data that is gathered in the real world, where there is no getting away from gravity, demands that this be so.

You haven't accepted the fact that SR is restricted to constant uniform, inertial motion, and applies to space with insignificant gravitational effects.

[timey]

Someone here should know
Minkowski, in generalizing the time coordinate from t to ict, a 4th dimension, produced a new format for the space-time diagram. Horizontal x, vertical ct. A straight line represents object speed over light speed, vt/ct = v/c = a speed plot. Without the scaling of time by c, a graph would be useless for analyzing motion at fractions of c. Another gain, the issue of the essence of 'time' is eliminated.

...and gravity is also absent from the spacetime diagram, yet experimental tests in reality where there is no escape from gravity show that special relativity is consistent.
This leads me to wondering what it is about special relativity calculations that are incorporating the factor of gravity into the equation.  The fact that special relativity is consistent with experimental data that is gathered in the real world, where there is no getting away from gravity, demands that this be so.

You haven't accepted the fact that SR is restricted to constant uniform, inertial motion, and applies to space with insignificant gravitational effects.

I know that the Schwarzschild metric is the solution of the Einstein field equations other than the trivial flat space solution.  And I know that Shapiro used c as the speed of light and calculated the time delay of the passage of light waves or rays over finite coordinate distance according to a Schwarzschild solution to the Einstein field equations.  I know the Shapiro effect is a test of general relativity, and incorporates SR via the equivalence principle. The fine print is that everything from SR, including the constant speed of light, applies.

I do understand the fact that SR is restricted to constant, uniform, inertial motion, and applies to space with insignificant gravitational effects, but I also understand that there are no gravitational effects in this universe that can be considered insignificant.  The Shapiro effect is a test of general relativity, where this is a measure of extreme differences in gravitational field, but special relativity applies.  Real world experimental testing of special relativity cannot remove itself entirely from the gravitational field in any part of space..  My point being that special relativity, despite being conducted in gravitational fields, remains consistent. 

[guest4091]

timey;

I do understand the fact that SR is restricted to constant, uniform, inertial motion, and applies to space with insignificant gravitational effects, but I also understand that there are no gravitational effects in this universe that can be considered insignificant.

In a remote location in space, distant (in astronomical terms) from large masses, the net gravitational effect is zero. It can be considered gravitational noise. tiny fluctuations in all directions, lasting femto seconds, similar to vacuum fluctuations. In the ideal world of calculations to the nth degree, there are gravitational effects. In the real world they are insignificant. Experiments are performed on the earth which ignore any effects from surrounding galaxies, (since they are insignificant).

[timey]

But Phyti - the Shapiro testing of general relativity wasn't an intergalactic experiment.

Remember also that special relativity is compatible with quantum mechanics...and that quantum mechanics and general relativity are not compatible.