Related papers: Invisible Matter
Dark Matter is one of the most intriguing riddles of modern astrophysics. The Standard Cosmological Model implies that only 4.5% of the mass-energy of the Universe is baryonic matter and the remaining 95% is unknown. Of this remainder, 22%…
A brief but broad survey is presented of the flows, forms and large-scale transformations of mass-energy in the universe, spanning a range of about twenty orders of magnitude (m_{Planck}/m_{proton}) in space, time and mass. Forms of energy…
In this article, we review a series of recent theoretical results regarding a conventional approach to the dark energy (DE) concept. This approach is distinguished among others for its simplicity and its physical relevance. By compromising…
A model for gravitational collapse where the event horizon is a quantum critical phase transition is extended to provide an explanation for the origin of the observable universe, where the expanding universe that we observe today was…
An overview is presented of a recently proposed "radically conservative" solution to the problem of dark energy in cosmology. The proposal yields a model universe which appears to be quantitatively viable, in terms of its fit to supernovae…
The old cosmological constant problem is to understand why the vacuum energy is so small; the new problem is to understand why it is comparable to the present mass density. Several approaches to these problems are reviewed. Quintessence…
An interaction between the vacuum energy and dark matter is an intriguing possibility which may offer a way of solving the cosmological constant problem. Adopting a general prescription for momentum exchange between the two dark components,…
The observational evidence for dark matter on progressively larger cosmic scales is reviewed in a rather pedagogical fashion. Although the emphasis is on dark matter in galaxies and in clusters of galaxies, its cosmological evidence as well…
The cosmological constant, which was introduced by Einstein a century ago to allow for a static universe, experienced a revival two decades ago under the label dark energy as a parameter to model the observed accelerated expansion of the…
The nature of dark matter is one of the most pressing questions in particle physics. Yet all our present knowledge of the dark sector to date comes from its gravitational interactions with astrophysical systems. Moreover, astronomical…
There are many indications that ordinary matter represents only a tiny fraction of the matter content of the Universe, with the remainder assumed to consist of some different type of matter, which, for various reasons must be nonluminous…
It is now, generally, believed that the presence of some form of dark matter is essential to explain the flat rotation curves of galaxies, and anomalous large velocities of galaxies in the clusters and superclusters. This dark matter turns…
Dark matter, proposed decades ago as a speculative component of the universe, is now known to be the vital ingredient in the cosmos, eight times more abundant than ordinary matter, one quarter of the total energy density and the component…
A probable solution of the cosmological constant problem was recently found. We propose that dark energy of the Universe is vacuum energy. Our Universe during its expansion is spending its vacuum energy for creation of new quantum states,…
In Cosmology and in Fundamental Physics there is a crucial question like: where the elusive substance that we call Dark Matter is hidden in the Universe and what is it made of?, that, even after 40 years from the Vera Rubin seminal…
Several works in the last few years devoted to measure fundamental probes of contemporary cosmology have suggested the existence of a delocalized dominant component (the "dark energy"), in addition to the several-decade-old evidence for…
The $\Lambda$-CDM model of cosmology has done much to clarify our picture of the early universe. However, there are still some questions that $\Lambda$-CDM does not necessarily answer; questions such as what is the fundamental nature of…
Following a short discussion of some unresolved issues in the standard model of cosmology (considered to be a generic LCDM model with flat geometry and an early period of inflation), an update on the current state of research regarding the…
These lecture notes provide a concise, rapid and pedagogical introduction to several advanced topics in contemporary cosmology. The discussion of thermal history of the universe, linear perturbation theory, theory of CMBR temperature…
All observational evidence for dark matter and dark energy is so far exclusively gravitational. Hence, the dark sector may be equivalently described by a theory of the spacetime metric whose dynamics is affected by interactions with an…