Dark Energy and the Preposterous Universe
نویسنده
چکیده
A brief review is offered of the theoretical background concerning dark energy: what is required by observations, what sort of models are being considered, and how they fit into particle physics and gravitation. Contribution to the SNAP (SuperNova Acceleration Probe) Yellow Book.
منابع مشابه
Formation of Large Structures in the Acceleration Universe with a Hybrid Expansion Law
In the current paper, we have studied the effect of dark energy on for-mation where dark energy exists in the background. For this purpose, we used both WMAP9 and Planck data to study how the radius changes with redshift in these mod-els. We used different data sets to fix the cosmological parameters to obtain a solution for a spherical region under collapse. The mechanism of structure formation f...
متن کاملپیامدهای اختر فیزیکی ماده تاریک سرد
There are several observational evidences for the existence of dark matter in the universe. More than about 90% of the matter in the universe is in a form which is not directly observable. If the dark matter is in the form of weakly interacting massive particles (WIMPs) or cosmions, part of it is captured by the Sun, other stars, and even planets. In this paper, some basic ideas of the cosmio...
متن کاملDark Matter and Dark Energy: The Critical Questions
Stars account for only about 0.5% of the content of the Universe; the bulk of the Universe is optically dark. The dark side of the Universe is comprised of: at least 0.1% light neutrinos; 3.5% ± 1% baryons; 29% ± 4% cold dark matter; and 66% ± 6% dark energy. Now that we have characterized the dark side of the Universe, the challenge is to understand it. The critical questions are: (1) What for...
متن کاملClassifying the Future of Universes with Dark Energy
We classify the future of the universe for general cosmological models including matter and dark energy. If the equation of state of dark energy is less then −1, the age of the universe becomes finite. We compute the rest of the age of the universe for such universe models. The behaviour of the future growth of matter density perturbation is also studied. We find that the collapse of spherical ...
متن کاملEarly and Late Transient Cosmic Acceleration Due to Curvature Inspired Dark Energy
In contrast to other models, here, it is obtained that dark energy emerges from the higher-derivative gravity with a non-linear term proportional to R with R being the Ricci scalar curvature. Interestingly, it is found that the universe begins with acceleration, which continues for a short period. Later on, universe decelerates driven by radiation and subsequently by matter. Two components of d...
متن کامل