Dark Energy

[geordief]

It seems like it may be a nasty fly in the ointment for GR. I know little about the subject and this is probably a stupid question...Could it  be regions of negative spacetime curvature?

 

I have heard it  described as perhaps something akin to an anti gravity so would that imply negative spacetime curvature?

 

Apologies for the level of ignorance

 

edit: on reflection isn't  Dark Energy everywhere and not confined to regions (unlike Dark Matter)?

If so ,it couldn't be negative spacetime curvature,could it?

Edited July 13, 2019 by geordief

[Strange]

2 hours ago, geordief said:

It seems like it may be a nasty fly in the ointment for GR

Not really. A "fly in the ointment" would be observations that conflicted with (or couldn't be explained by) GR. So far, there are none of those. (Which is a bit disappointing.)

It is just adding another parameter to the equations. Actually, not even adding a new parameter; just adjusting the value of one that has been adjusted several times in the past as new evidence came to light. Initially, Einstein gave it a negative (I think) value to make the universe stationary- because that was the assumed state of the universe at the time. When the universe was found to be expanding, the value was set to zero. Then, some observations (which turned out to be incorrect) suggested the universe should be much older and so the value was changed again. The more measurements were made and the value went back to ero. Then dark energy was spotted so the value was changed again to account for that.

Currently, the are two different estimates for the expansion rate (and hence age) of the universe based on different measurement techniques. These might reveal new physics. Which might mean changes to GR or a new theory or ...

2 hours ago, geordief said:

edit: on reflection isn't  Dark Energy everywhere and not confined to regions (unlike Dark Matter)?

Yes. (So you have answered your own question!)