Argument by analogy

[Gibsense]

Gibsense, we must, as always, watch the semantics.

A background can be construed as static, but we are discussing cosmic microwave radiation, which is not static.

Can a background be static when it is composed of radiation moving at the speed of light?

If we discussed the cosmic background radiation, would this ease matters between us?

Quite right! I must pay more attention!
Re Background. The radiation of the CMB is of course everywhere. Assuming the universe is spherical the photons are zipping around as they have been for around 13.8 billion years. Presumably many have decohered as they encountered matter

If this makes any sense it occurs to me as I type that some may encounter a virtual particle in the brief period of its existence. Presumably, that would mess up their annihilation procedure (?).

Back to the subject: https://en.wikipedia.org/wiki/Cosmological_principle
Scroll down and you get - The cosmic microwave background (CMB) provides a snapshot of a largely isotropic and homogeneous universe. The largest scale feature of the CMB is the dipole anisotropy; it is typically subtracted from maps due to its large amplitude. The standard interpretation of the dipole is that it is due to the Doppler effect caused by the motion of the solar system with respect to the CMB rest-frame.

 

[Gibsense]

Is it safe to assume that we are always moving, and that what we see is always moving? If that is true then a static condition could not exist, whether we can measure it or not. Position and intensity and frequency would always be changing. Just like radio static.



A fixed state of change. A static of change.

I would contend that the 'natural' state of matter is approximately 'at rest' - stationary - but that gradual differences result in clumping and evolution will cause movement

 

[Catastrophe]

The radiation of the CMB is of course everywhere.

This does not mean that the radiation is static.

Photons do not stop moving because they are everywhere.
They would not get everywhere if they were static.
You state that "radiation is of course everywhere". If static, how does radiation get everywhere?

Light from the Sun pervades our Solar System, but it does not mean that all photons and other radiation become stationary = static. Otherwise light would not move from the Sun. Not radiate.

Radiation is not static, however far it reaches.

Cat