From what was stated, I assume ΩΛ.timmdeeg said:What do you mean by saying a "proportion of dark energy"? It's density is constant and a tenth of it too.
Dark energy density proportion refers to the fraction of the total energy density of the universe that is attributed to dark energy. Current observations suggest that dark energy makes up about 68-70% of the total energy density of the universe.
The dark energy density proportion is determined through a combination of observational data, including measurements of the cosmic microwave background radiation, the large-scale structure of the universe, and the rate of expansion of the universe (Hubble constant). These observations are analyzed using models of cosmology, such as the Lambda Cold Dark Matter (ΛCDM) model.
Dark energy is important in cosmology because it is believed to be the driving force behind the accelerated expansion of the universe. Understanding dark energy helps scientists to explain the observed large-scale structure of the universe and the future evolution of cosmic expansion.
The leading theories about the nature of dark energy include the cosmological constant (Λ), which is a constant energy density filling space homogeneously, and dynamic dark energy models such as quintessence, which propose that dark energy density can vary over time. Another possibility is that our understanding of gravity might need to be modified on cosmological scales.
The dark energy density proportion significantly affects the fate of the universe. If dark energy continues to dominate, the universe will keep expanding at an accelerating rate, potentially leading to a "Big Freeze" where galaxies, stars, and eventually atoms are spread so far apart that the universe becomes cold and dark. Other scenarios, such as a "Big Rip" or a "Big Crunch," depend on the properties of dark energy and how it evolves over time.