31 July 2024

Is space-time dilation conceptually equivalent to space-time expansion?


Relativistic space-time is described as a four-dimensional continuum comprising three dimensions of space and one dimension of time. In this framework, space and time are interwoven, forming an integrated space-time fabric. As time dilates due to relativistic effects, does this interconnected nature imply a dilation of space-time as a whole?

For context:

Cosmic Expansion: Describes how the distance between cosmic objects increases over time, which can be represented as:

t₀ < (t₀+Δt) = t₁ → (x₀,y₀,z₀,t₀) < (x₁,y₁,z₁,t₁)

Where (t₁ - t₀) = elapsed time.

Space-Time Dilation: Reflects how time dilation in relativistic contexts affects space-time coordinates:

t < t′ → (x,y,z,t) < (x′,y′,z′,t′)

Where t′ is dilated time

Given these representations, can the concept of space-time dilation be viewed as a form of space-time expansion in terms of their consequences?

Cosmic expansion is not relativistic distortion in space-time but rather a distinct large-scale cosmological phenomenon:

Cosmic expansion is not a relativistic effect nor is it a subject of relativity in the same sense as relativistic space-time dilation. Cosmic expansion refers to the large-scale increase in distances between cosmic objects, driven by phenomena such as dark energy or anti-gravitational fields. In this view, the increase in distances between cosmic objects describes the expansion of space over time.

This is distinct from the dilation of relativistic space-time, which concerns local variations in space and time due to relative motion or gravitational fields.

Thus, the recession of galaxies due to dark energy or anti-gravitational effects is not an expansion of relativistic space-time but rather a large-scale cosmological phenomenon.