Question

It is undeniable that spacetime is medium for gravitational waves propagation as first confirmed by LIGO experiment having elasticity and compressability.

However, for electromagnetism space has the total opposite behavior effectively portrayed as an analogue of a perfect incompressible fluid in the worst case and as superfluous in the best case, not needed for EM waves propagation at all.

Seems to me that the definition of vacuum free space for these two different phenomena gravity and EM suffers from bipolar disorder and is schizophrenic at least.

Additionally, I find it troublesome how these different phenomena allegedly one of propagating without a medium (i.e. EM) share the same speed of propagation c inside the vacuum which c is clearly an intrinsic physical property of free space c=1/sqrt(μ0ε0) according to electromagnetism theory?

So what is the resolution of these two conflicting descriptions about space?

Is vacuum space a medium of energy propagation or not? It can't be both?

Answer 1

The misconception that vacuum space must behave like a material medium for the propagation of gravitational and electromagnetic waves is resolved by the understanding of general relativity and Maxwell's equations. Gravitational waves travel through spacetime itself, while EM waves do not need a medium to propagate because they consist of self-perpetuating electric and magnetic fields. Both propagate at the universal constant speed 'c' due to the intrinsic properties of spacetime.

Step-by-step explanation:

The seeming contradiction in how vacuum space is described with regards to gravitational waves and electromagnetic waves (EM) is resolved by understanding the nature of these phenomena and how they interact with spacetime. Gravitational waves are ripples in the fabric of spacetime itself, predicted by Einstein's theory of general relativity, and propagate at the speed of light without needing a medium because they are not waves in a medium, but of spacetime itself. On the other hand, electromagnetic waves, described by Maxwell's equations, can travel through a vacuum because they consist of oscillating electric and magnetic fields that perpetuate each other's existence. That both gravitational and electromagnetic waves propagate at the speed of light in a vacuum is a reflection of the intrinsic properties of spacetime and not the requirement of a material medium.

The notion of the 'aether' was discarded after experiments like Michelson-Morley showed no evidence of its existence, reinforcing that EM waves do not need a medium. Instead, the constant speed of light in a vacuum (c) is derived from and exemplifies the fundamental properties of free space, which are characterized by the electric permittivity (ε0) and the magnetic permeability (μ0) of the vacuum. Thus, the vacuum is not a medium in the traditional sense but does have properties that allow for the propagation of energy and information via these waves at the universal constant speed 'c'.