Recent content by hnaghieh

When did I ever say spacetime coordinates are invariant? What said was : under approximate transformation laws relating the coordinate basis of all coordinate systems in relative motion with respect to each other the spacetime distance will be invariant “ same for all observers” Just as you...

And Mr Albert Einstein said no. Sorry you are wrong.

Absolute space and absolute time.

That is exactly what Newton said.

Ok thank you all for your patience . I think I have my answer.

Two different “ spacelike “ intervals can never be “invariant” just as two “ timelike “ intervals can never be invariant. It is only “spacetime “ intervals that are invariant under approximate transformation equations

The interval is invariant “same for all observers “ only with the appropriate transformation equations relating the frame depandant components of one frame with another frame with relative velocity.Under these appropriate transformation equations all observers agree. Because they know it was...

The observer in each frame will determine that interval or “distance “ if you prefer, in their rest frame using rods and clocks of their frame (propertime and proper length). When they compare they don’t agree what the length of that distance is unless they know the relationship between their...

No. I am talking about an invariant spacetime interval viewed from two different reference fame which have a relative velocity with respect to each other.

One of The people I have heard using these terms: “a moving reference frame” or “ a frame moving relative to me” is the great inventor of all this. Mr Albert Einstein in his celebrated paper “on the electrodymamics of moving bodies”

I totally agree and apologize for sloppy statement. Instead of just “vector” i should have put The words “components of vector “ in the parentheses. What I meant was components of tensor, as well as the components of vectors, are coordinate frame dependent.

This is the crucial point. A detector making “time” measurement can not make “space” at the same time with unrestricted accuracy because of finite velocity of light. These two parameters (time and space)are orthogonal parameters. In the time it takes for the signal to reach the detector, the...

This is Galilean principle of relativity. Precursor to Einstein’s principle of relativity. Not related to “color love”or “weight of an idea “ which are not physical parameters. It simply means motion is relative not absolute. We Need a frame of reference in order to give its magnitude or its...

I apologize for lack of clarity in my statement. I assumed you were referring to minkowskie’s geographical representation of time like and space like worldlines as orthogonal axies on a spacetime diagram. And That he represented the respective coordinate axies of a reference frame with a...

In order to make any calculation we need data or measurements. In order to have measurements we need units of measurements(yard sticks and clocks). Yard sticks and clocks are frame dependent in the sense that two reference coordinate systems in relative motion will have different units (due to...