I Dark energy and expansion of space

[kodama]

universe is expanding since the bigbang so therefore space is expanding, but apparently dark energy remains constant, it apparently isn't getting diluted as the universe expands

is energy being created, specifically the energy in vacuum?

 

[phinds]

universe is expanding since the bigbang so therefore space is expanding, but apparently dark energy remains constant, it apparently isn't getting diluted as the universe expands

is energy being created, specifically the energy in vacuum?

"Space is expanding" is not correct. Google "metric expansion" for a discussion.

Yes, dark energy is being created as bound systems get farther apart from each other. The density of dark energy remains the same.

 

[no-ir]

Yes, dark energy is being created as bound systems get farther apart from each other. The density of dark energy remains the same.

Hm, do you know of any experimental evidence that dark energy density is constant in time, or is this just an assumption? Specifically, do you have any reason to believe that the average dark energy density is not inversely proportional to the "total volume"; i.e. that the "total dark energy content" is not constant after all?

 

[phinds]

Hm, do you know of any experimental evidence that dark energy density is constant in time, or is this just an assumption? Specifically, do you have any reason to believe that the average dark energy density is not inversely proportional to the "total volume"; i.e. that the "total dark energy content" is not constant after all?

My references are all just other posts (by knowledgeable people) here on this forum. It is not an assumption, it is taken as empirically-based fact but I can't point you to a study saying so. I don't mean to imply that there aren't any, just that I don't have a citation for you.

 

[haushofer]

"Space is expanding" is not correct.

What do you mean by this? Isn't spacetime defined by a manifold with a metric on it? :)

 

[phinds]

What do you mean by this? Isn't spacetime defined by a manifold with a metric on it? :)

Google "metric expansion"