The Dark Age of the Universe
... available coolant is H2. Because two hydrogen atoms cannot form a molecule by colliding and emitting a photon, only a small fraction of the gas in these first objects could become H2 via reactions involving the species H⫺ and H2⫹, formed by the residual free electrons and protons left over from the ...
... available coolant is H2. Because two hydrogen atoms cannot form a molecule by colliding and emitting a photon, only a small fraction of the gas in these first objects could become H2 via reactions involving the species H⫺ and H2⫹, formed by the residual free electrons and protons left over from the ...
Computer Simulation of Dark Matter Effects on Galaxy Collisions
... program was written in C, and this year that program has been modified to fit this year’s problem. This year, the code has been modified to do two galaxies and include galaxygalaxy interactions. Currently, for this model dark matter is being treated by a large mass point at the center of the galaxy. ...
... program was written in C, and this year that program has been modified to fit this year’s problem. This year, the code has been modified to do two galaxies and include galaxygalaxy interactions. Currently, for this model dark matter is being treated by a large mass point at the center of the galaxy. ...
B Non-Conservation, Cold Dark Matter and Subpreon Model § 1
... viewpoint, neutrinos with the tiny mass are a candidate of the dark matter (hot dark matter). The cosmology shows, however, that hot dark matter-is unfavorable and cold dark matter is relevant. 4 ) This suggests the necessity of physics beyond the standard model. It will be one of the important test ...
... viewpoint, neutrinos with the tiny mass are a candidate of the dark matter (hot dark matter). The cosmology shows, however, that hot dark matter-is unfavorable and cold dark matter is relevant. 4 ) This suggests the necessity of physics beyond the standard model. It will be one of the important test ...
Cosmological Applications of Gravitational Lensing
... Schneider et al 1988 not much dark matter in galactic cores Narasimha et al 1986 evidence of compact masses ~ 1010 solar masses in center of lenses Galactic halos models can give mass distribution as well as mass of lenses Existence of lens candidates with no detected lensing galaxy ...
... Schneider et al 1988 not much dark matter in galactic cores Narasimha et al 1986 evidence of compact masses ~ 1010 solar masses in center of lenses Galactic halos models can give mass distribution as well as mass of lenses Existence of lens candidates with no detected lensing galaxy ...
pptx
... Edwin Hubble measured distances to Slipher’s galaxies. He found that galaxies with higher velocities away from us (higher redshifts) have larger distances from us. This correlation between distance and velocity is known as the Hubble Law. ...
... Edwin Hubble measured distances to Slipher’s galaxies. He found that galaxies with higher velocities away from us (higher redshifts) have larger distances from us. This correlation between distance and velocity is known as the Hubble Law. ...
Gravitational Lensing: An Unique Probe of Dark Matter and Dark...
... infinite magnification called critical lines. Transferred to the source plane these line become caustics. The location of these lines depends on the relative distances of the source and lens and, of course, the distribution of matter in the lens. The position of the background source with respect to ...
... infinite magnification called critical lines. Transferred to the source plane these line become caustics. The location of these lines depends on the relative distances of the source and lens and, of course, the distribution of matter in the lens. The position of the background source with respect to ...
runaway - Astronomy & Astrophysics Group
... “I have observed the nature and the material of the Milky Way. With the aid of the telescope this has been scrutinized so directly and with such ocular certainty that all the disputes which have vexed philosophers through so many ages have been resolved, and we are at last freed from wordy debates a ...
... “I have observed the nature and the material of the Milky Way. With the aid of the telescope this has been scrutinized so directly and with such ocular certainty that all the disputes which have vexed philosophers through so many ages have been resolved, and we are at last freed from wordy debates a ...
Particle Physics and Cosmology
... • All known particles are easily eliminated. • Dark matter is the best evidence that the standard model of particle physics is incomplete, and motivates many extensions. • Some candidates: – WIMPs (e.g., neutralinos) – Axions 21 August 2003 ...
... • All known particles are easily eliminated. • Dark matter is the best evidence that the standard model of particle physics is incomplete, and motivates many extensions. • Some candidates: – WIMPs (e.g., neutralinos) – Axions 21 August 2003 ...
Dark matter
Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but would account for most of the matter in the universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, on radiation, and on the large-scale structure of the universe. Dark matter has not been detected directly, making it one of the greatest mysteries in modern astrophysics.Dark matter neither emits nor absorbs light or any other electromagnetic radiation at any significant level. According to the Planck mission team, and based on the standard model of cosmology, the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Thus, dark matter is estimated to constitute 84.5% of the total matter in the universe, while dark energy plus dark matter constitute 95.1% of the total mass–energy content of the universe.Astrophysicists hypothesized the existence of dark matter to account for discrepancies between the mass of large astronomical objects determined from their gravitational effects, and their mass as calculated from the observable matter (stars, gas, and dust) that they can be seen to contain. Their gravitational effects suggest that their masses are much greater than the observable matter survey suggests. Dark matter was postulated by Jan Oort in 1932, albeit based upon insufficient evidence, to account for the orbital velocities of stars in the Milky Way. In 1933, Fritz Zwicky was the first to use the virial theorem to infer the existence of unseen matter, which he referred to as dunkle Materie 'dark matter'. More robust evidence from galaxy rotation curves was discovered by Horace W. Babcock in 1939, but was not attributed to dark matter. The first hypothesis to postulate ""dark matter"" based upon robust evidence was formulated by Vera Rubin and Kent Ford in the 1960s–1970s, using galaxy rotation curves. Subsequently, many other observations have indicated the presence of dark matter in the universe, including gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, the temperature distribution of hot gas in galaxies and clusters of galaxies and, more recently, the pattern of anisotropies in the cosmic microwave background. According to consensus among cosmologists, dark matter is composed primarily of a not yet characterized type of subatomic particle.The search for this particle, by a variety of means, is one of the major efforts in particle physics today.Although the existence of dark matter is generally accepted by the mainstream scientific community, some alternative theories of gravity have been proposed, such as MOND and TeVeS, which try to account for the anomalous observations without requiring additional matter. However, these theories cannot account for the properties of galaxy clusters.