Is Dark Energy Taking Over?

Question

First question, trying to keep it simple 😃

Because it's constant it grows in magnitude as the universe expands, whereas normal matter does not? Is this accurate as far as we know?

Answer 1

Is dark energy taking over?

Short answer: yes.

Longer answer: yes, probably. We aren't certain about how the density of dark energy will evolve as the universe expands, but in the simplest models the density of dark energy stays constant. This is unlike dark matter (the next largest component of the universe) and ordinary matter, whose density will decrease as the universe expands. So, yes, we believe that dark energy will represent a larger and larger proportion of the universe as it expands.

Answer 2

Depends on the scale. The way we interpret the observations is that we have bound clusters of galaxies that aren't expanding. Matter dominates the energy density in these clusters. On smaller scales, matter is concentrated into galaxies, star clusters, planetary systems, stars, etc. For these smaller concentrations, matter is even more dominant. In these systems, dark energy isn't driving the evolution and is not "taking over".

However, on larger scales, dark energy is separating the clusters from each other. So, we expect that the next phase of evolution of the universe will involve vast empty space, dominated by dark energy, sparsely occupied by isolated clusters of galaxies.

Answer 3

From the Wikipedia page on dark energy:

The density of dark matter in an expanding universe decreases more quickly than dark energy, and eventually the dark energy dominates.

The article has a section called “Implications for the fate of the universe” which goes into more detail.