Related papers: Possible origin of Larson's lows
The observed excess of gravitational forces in galaxies and galactic clusters is usually referred as the existence of "dark matter particles" of unknown origin. An alternative explanation of the dark matter effect is presented here by…
In the present paper we consider special classes of tensor-multi-scalar theories of gravity whose target-space metric admits Killing field(s) with a periodic flow. For such tensor-multi-scalar theories we show that if the dynamics of the…
The high-energy Universe is potentially a great laboratory for searching new light bosons such as axion-like particles (ALPs). Cosmic sources are indeed the scene of violent phenomena that involve strong magnetic field and/or very long…
The existence of multiple regions of space beyond the observable Universe (within the so-called "multiverse") where the vacuum energy density takes different values, has been postulated as an explanation for the low non-zero value observed…
We consider the consequences of applying general relativity to the description of the dynamics of a galaxy, given the observed flattened rotation curves. The galaxy is modeled as a stationary axially symmetric pressure-free fluid. In spite…
We revise the statistical properties of the primordial cosmological density anisotropies that, at the time of matter radiation equality, seeded the gravitational development of large scale structures in the, otherwise, homogeneous and…
It has been proposed that the Galaxy might contain a population of cold clouds in numbers sufficient to account for a substantial fraction of the total mass of the Galaxy. These clouds would have masses of the order of 10^{-3} Solar mass…
Early JWST observations have revealed the ubiquitous presence in the early Universe, up to z about 16, of extreme baryon concentrations, namely forming globular clusters, extremely dense galaxies that may or may not be UV bright, and…
We investigate the condition for the formation of micron-sized grains in dense cores of molecular clouds. This is motivated by the detection of the mid-infrared emission from deep inside a number of dense cores, the so-called `coreshine,'…
Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious "dark matter" component, which does not interact via electromagnetism and thus neither…
Matter in the universe has become ``dark'' or ``missing'' through misconceptions about the fluid mechanics of gravitational structure formation. Gravitational condensation occurs on non-acoustic density nuclei at the largest Schwarz length…
In the past years a wealth of observations has unraveled the structural properties of the Dark and Luminous mass distribution in spirals. These have pointed out to an intriguing scenario not easily explained by present theories of galaxy…
The notion of `adhesion' has been advanced for the phenomenon of stabilization of large-scale structure emerging from gravitational instability of a cold medium. Recently, the physical origin of adhesion has been identified: a systematic…
Einstein gravitation is known to give rise to the formation of singularities at high densities unless the dominant energy condition is made invalid by the occurrence of new physics: we show that such a new physics can be the already present…
Gleason's theorem is a fundamental 60 year old result in the foundations of quantum mechanix, setting up and laying out the surprisingly minimal assumptions required to deduce the existence of quantum density matrices and the Born rule. Now…
Galaxies are gigantic physical systems having a typical size of many tens of thousands of light years. Thus any change at the center of the galaxy will affect the rim only tens of millennia later. Those retardation effects seems to be…
The fraction of substructures required to account for anomalous flux ratios in gravitational lens systems appears to be higher than that predicted in the standard cold dark matter cosmology. We present a possible alternative route to…
The cold dark matter model successfully explains both the emergence and evolution of cosmic structures on large scales and, when we include a cosmological constant, the properties of the homogeneous and isotropic Universe. However, the cold…
The evidence of the phenomenon for which, in galaxies, the gravitating mass is distributed differently than the luminous mass, increases as new data become available. Furthermore, this discrepancy is well structured and it depends on the…
Modified Newtonian Dynamics (MOND) has long been known to fail in galaxy clusters, implying a residual missing mass problem for clusters in this context. Here, using mass profiles derived from strong- and weak-lensing shear, as well as…