Questions tagged [dark-energy]

Questions regarding the as-yet-unknown energy permeating the universe that is responsible for its expansion.

7 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
2
votes
0answers
54 views

Definition of space - to cope with “space expansion”

I've searched quite a lot but found no satisfying definition, so please: How do we actually define space when talking of "space expansion"? Isn't it just a metric, a dimension we measure, instead of ...
2
votes
1answer
115 views

The energy density of DM (to be fluid,state parameter=-2)increases with time. Does it violate the concept of accelerating universe?

We know that dark energy with value of state parameter $\omega<-1$ is called phantom dark energy model. In this model if we assume dark energy to be a fluid with value of state parameter $\omega=-2$...
2
votes
1answer
93 views

Can eternal inflation and gravity explain dark energy?

First of all, I have absolutely no background in astronomy and physics. I just watch a lot of "i-hope-scientific" youtube channels talking about physics and astrophysics and I can kind of follow the ...
1
vote
0answers
32 views

Formula to Compute sigma8 for correction in non-linear regime

I try to explain my issue on this forum since it seems to be appropriate. I need to apply a correction on $\sigma_{8}$ between linear and non-linear regime to keep it fixed (I make change the values ...
1
vote
0answers
52 views

How are constraints on dark energy improved the most?

Today we have various data available from independent probes to constrain dark energy, i.e. its equation of state $w$. These include Type 1a supernovae, BAO, CMB, large-scale galaxy surveys, etc. Are ...
0
votes
0answers
45 views

Could the impresssion of a accelerated expansion of the universe come from a loss of energy of light on a large scale of time?

How do we know that redshift is not the result of energy loss or wave expansion of light on a large scale of millions of years that we have never been able to observe? How can we exclude the ...
-3
votes
1answer
111 views

In what form was dark energy stored 6 billion years ago?

Bearing in mind the provisions of the 1st Law of Thermodynamics, which decrees that energy can neither be created nor destroyed, all the energy in the Universe must have been there at the time of the ...