Why do galaxies move away faster when they are further away?

The rubber band shows this quite clearly

https://www.youtube.com/watch?v=wZdIImE-RY8

Therefore, the expansion is not indicated at a fixed speed, but at the…

Hubble constant

Assuming a linear extension of the universe, the scale factor a(t)=D(t)/D0 of any distance D and the distance D0 at time t0 in the universe is linearly dependent on time t:

a = da/dt*t (1) with an expansion speed

da/dt = H*a (2)

The factor H is the stroke lead constant (which should be called better stroke lead parameters because it is not constant – in fact follows from a linear expansion constant expansion speed da/dt and thus H=1/t with 1 in 2), has a pole point at the Big Bang and has since then decreased, but never becomes zero.

Cosmological horizon

With the speed of light c it is now possible to define a radius rH=c/H, which is called the stroke lead radius. For D = rH, the speed v(rH) = c, i.e. theoretically, objects are removed at this distance at the speed of light from us and one could think that one can never see these objects because their light does not come against the speed of expansion, but:

1. Light directly behind rH can, once sent out, create with time within rH and ultimately reach us – the correct invoice contains an integration of the movement of co-moved coordinates and the light signal from t0 to infinite and leads here too far – also…

2. the above-mentioned assumption of the linear extension is incorrect. The expansion is subject to braking and accelerating influences (e.g. the mass density including dark matter vs. dark energy), the strength of which was not temporally constant or will be. Depending on these influences, the cosmological horizon can expand further with predominant braking and make more objects visible, or shrink and hide more objects with predominant acceleration.

For these two reasons, the cosmological horizon is not attributable to the hub radius, but at the current level somewhat behind it (about LJ 16 billion instead of LJ 13.4 billion). With further expansion of the universe and decreasing mass density, the acceleration could gain – then the stroke pale parameter would decrease to a constant value: the solution for the differential equation da/dt=const*a is then an exponential extension, which finally allowed the cosmological horizon to shrink to structures directly bound by gravity, and the remainders of the combination of Milky Way and NGC224 would be in the dark alone.