- #1

say_cheese

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- TL;DR Summary
- The time constant of instability corresponding to the Hubble derived mass density is 10^11 years (without a Cosmological Constant). Why is this not an explanation for the observed acceleration of the expansion of the universe?

Ref: Principles of Physical Cosmology by P.J.E. Peoples, Princeton Univ. Press

This question is likely fully answered somewhere, but I cant find it.

Hubble obtained (1926) the mean mass density of the Universe as 10^-31 g/c.c. The gravitational stability equation gives (McCrea, Milne (1934)) with no dark energy cosmological constant,

later derivation without division by 3.

The resulting exponential time constant for the Gravitational Instability from this equation and the Hubble density is 10^11 years, much longer than the current age of the Universe.

The instability can result in increasing expansion, if the density perturbation is negative. Why is this not an explanation for the observed acceleration in the expansion of the Universe?

This question is likely fully answered somewhere, but I cant find it.

Hubble obtained (1926) the mean mass density of the Universe as 10^-31 g/c.c. The gravitational stability equation gives (McCrea, Milne (1934)) with no dark energy cosmological constant,

later derivation without division by 3.

The resulting exponential time constant for the Gravitational Instability from this equation and the Hubble density is 10^11 years, much longer than the current age of the Universe.

The instability can result in increasing expansion, if the density perturbation is negative. Why is this not an explanation for the observed acceleration in the expansion of the Universe?