The Folly of Theoretical Physicists
Theoretical physicists often repeat the saying, “Spacetime tells matter how to move; matter tells spacetime how to curve.”
This quote is credited to John Archibald Wheeler.
"John Archibald Wheeler was an American theoretical physicist largely responsible for reviving interest in general relativity in the United States after World War II."
That simply means he was presenting a 'simple' version for the public, not directly from Einstein (who never said the above).
When I read this phrase for the first time in late 2018, I thought it was one of the most STUPID statements I ever read concerning physics.
I discovered this quote is repeated by many physicists of different status or renown.
That repulsive reaction gave me the incentive to discover how any physicist could come to believe such a laughable statement.
Stupid is defined as "having or showing a great lack of intelligence or common sense"
Perhaps some might say I am too harsh, but considering the fame of those making the statement, I am not.
A valid response to hubris is ridicule.
I am an electrical engineer with physics during both high school and college. I cannot believe that statement.
I retired from a career working with high speed, precision machines. These machines can have variable kinematics with motorized attachments being mounted and dismounted as needed, and with many configurable coordinate systems.
Each dimension is scaled for convemience (like inches, millimeters, or degrees) and has a defined reference (i.e., where on that dimension is the zero value).
Kinematics is the definition of the respective motions of the machine hardware components. The machine has 1 or more bodies moving in each of 4 directions, left/right, up/down, in/out, and in rotation.
Every physical body in motion has 1 or more feedback devices. These are mounted either directly or with gears or belts.
Every coordinate system describes how a position is measured using its defined dimensions.
If the operator or programmer wants the machine at the precise location of X+1.2, Y-3.4, Z+5.6, C+90.0, everyone knows where that location is on the machine with their currently active coordinate system.
Nothing moves to a coordinate in any of these machines except when the computer uses the motors and feedback devices to move the respective machine components to arrive at that location.
Every machine has an operator jog mode. The operator selects an axis, then as long as they hold down a + or - button that axis continues its motion in that direction.
While moving and after the motion stops, the operators display always shows the current axis location. The coordinate system allows the operator to have current positions measured continually but nothing moves as if phsically restricted to any defined dimensions.
Every coordinate system in use is referenced to the physical space of the machine.
My experience with coordinate systems is the basis for my ricule of space-time in cosmology.
Theoretical physicists get this laughable claim by misunderstanding relativity.
The theory of relativity is a background independent theory meaning it never uses physical coordinates. All its tensor equations are confined to the observer's reference frame. Relativity by its very design never affects any physical entity, Only the observer's reference frame is affected (which is not a real thing) whose dimensions can be curved in this mathematical exercise for a gravitational field.
When confined by the math to the moving observer's reference frame space-time and its curvature should never be applied beyond a moving observer especially not to the cosmos.
Postulates of special relativity
1. First postulate (principle of relativity)
The laws of physics take the same form in all inertial frames of reference.
2. Second postulate (invariance of c)
As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. Or: the speed of light in free space has the same value c in all inertial frames of reference.
The two-postulate basis for special relativity is the one historically used by Einstein, and it remains the starting point today. As Einstein himself later acknowledged, the derivation of the Lorentz transformation tacitly makes use of some additional assumptions, including spatial homogeneity, isotropy, and memorylessness. Also Hermann Minkowski implicitly used both postulates when he introduced the Minkowski space formulation, even though he showed that c can be seen as a space-time constant, and the identification with the speed of light is derived from optics.
Léon Foucault who obtained a value of 298000 km/s [for the speed of light] in 1862.
< General Relativity >
General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of partial differential equations.
The 2nd postulate says c is a constant but the speed of light was already known to be constant.
I cannot find a reference for when the Doppler effect was first demonstrated in light.
Now we know, the velocity of the source of light has no effect on the velocity of light from the source but that velocity of the source shifts the wavelengths based on the direction of motion relative to the direction of propagation.
Relativity is a background independent theory meaning it never uses physical coordinates. All its tensor equations are confined to the observer's reference frame. Relativity by its very design never affects any physical entity, just the observer's reference frame whose dimensions can be curved in this mathematical exercise.
When cosmology tries to apply general relativity the context for spacetime is still confined to the moving observer's reference frame. This reference frame uses no coordinates in physical space.
Nothing in the universe is a moving observer with a non-inertial reference frame.
Nothing in the universe moves according to a coordinate system.
Verything in the universe moves as a result of forces. A change in kinetic energy requires a transfer of energy,
A coordinate system is not a source of energy.
The bending of light by space-time has been proposed.
The propagation of the synchronized electric and magnetic fields is affected only by the medium, as defined by its diffraction index.
Light will never follow a path defined by a coordinate system.
Believing anything moves as directed by a coordinate system is simply foolish.
Some theoretical physicists appear detached from reality but apparently reside in a manipulated coordinate system lacking a connection to physical space.
Classical physics was grounded in physical space with an established time increment for precise measurements otaining valid evidence fior experiments to these theories.
Theories lacking evidence are just place-holders awaiting testing for either falsified or possible confirmation.
New conflicting evidence can falsify previously accepted theories.
Science is the accumulation of knowledge but evidence, not any number of theories, marks the progress of science.