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
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Reproduce and plot myself from a paper with appropriate scripts and Fisher/Covariance matrixes

I would like to reproduce and plot myself the figure below. This plot, even it begins to date, is full of informations for me. The paper is located here : paper Suzuki et al. 2011 I have contacted ...
2
votes
0answers
58 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
129 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
128 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
66 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
54 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 ...
-3
votes
1answer
115 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 ...