Nonminimal global monopoles and bound orbits
... An interesting property of global monopoles is that they are configurations with energy density decreasing with the distance as r−2 [1]. This is very suggestive in view of the fact that, naively at least, this is precisely what seems to be required to provide a natural explanation for the flatness o ...
... An interesting property of global monopoles is that they are configurations with energy density decreasing with the distance as r−2 [1]. This is very suggestive in view of the fact that, naively at least, this is precisely what seems to be required to provide a natural explanation for the flatness o ...
Galaxies 1) What are galaxies? 2) The birth of galaxies 3
... They don’t contain many star forming regions, as they have used the bulk of their stellar material early in their formation. The massive size of galaxies of this type can be attributed to several galactic mergers, an event prone to advancing star formation activity Spiral and Barred Spiral Galaxies: ...
... They don’t contain many star forming regions, as they have used the bulk of their stellar material early in their formation. The massive size of galaxies of this type can be attributed to several galactic mergers, an event prone to advancing star formation activity Spiral and Barred Spiral Galaxies: ...
Messing Up a Galaxy
... It's interesting to note how astronomers know the difference — but there is a telltale observation that they can make. The largest of these clumps of material is the dwarf galaxy that has been named NGC 5291N. If this were a primitive dwarf galaxy from the early history of the Universe, it would con ...
... It's interesting to note how astronomers know the difference — but there is a telltale observation that they can make. The largest of these clumps of material is the dwarf galaxy that has been named NGC 5291N. If this were a primitive dwarf galaxy from the early history of the Universe, it would con ...
Clusters of Galaxies
... These early rocket results were entirely serendipitous, as no one had any idea that clusters of " galaxies should be luminous x-ray sources. Thus the study of clusters, as so much in the field of x-ray astronomy, was entirely an unexpected discovery. " • the first all sky x-ray survey, with the Uhu ...
... These early rocket results were entirely serendipitous, as no one had any idea that clusters of " galaxies should be luminous x-ray sources. Thus the study of clusters, as so much in the field of x-ray astronomy, was entirely an unexpected discovery. " • the first all sky x-ray survey, with the Uhu ...
"Star Tracks", Leaflet for Royal Society Summer Exhibition
... history of the Galaxy? For instance, we would like to know where and when the Sun was born. An individual star experiences many different Galactic environments throughout its life. Spiral arms can cause stars to move from one orbit to another as they age, so by studying the correlation between age a ...
... history of the Galaxy? For instance, we would like to know where and when the Sun was born. An individual star experiences many different Galactic environments throughout its life. Spiral arms can cause stars to move from one orbit to another as they age, so by studying the correlation between age a ...
Virtual Science Fair - Dark Matter Alexander Mashaal
... Dark Matter: In cosmology, dark matter has matter particles that cannot be spotted by their releases of radiation but when they are there, they can be taken from gravitational effects on visible matter such as stars and galaxies. Black Holes: A black hole is a part of space that has so much mass con ...
... Dark Matter: In cosmology, dark matter has matter particles that cannot be spotted by their releases of radiation but when they are there, they can be taken from gravitational effects on visible matter such as stars and galaxies. Black Holes: A black hole is a part of space that has so much mass con ...
The initial conditions and the large
... model cosmic structure formation in the NL regime • A proposal: remapping of 2LPT in the mildly nonlinear regime FL, Jasche, Gil-Marín, Wandelt 2013, arXiv:1305.4642 ...
... model cosmic structure formation in the NL regime • A proposal: remapping of 2LPT in the mildly nonlinear regime FL, Jasche, Gil-Marín, Wandelt 2013, arXiv:1305.4642 ...
The Herschel view on the dust properties of the Large Magellanic
... • Motivations. The electromagnetic emission from a galaxy contains information about the physical conditions therein experienced. In star forming regions, most of the power is reradiated by dust, in the infrared. The knowledge of the grain properties (their abundance, chemical composition and size d ...
... • Motivations. The electromagnetic emission from a galaxy contains information about the physical conditions therein experienced. In star forming regions, most of the power is reradiated by dust, in the infrared. The knowledge of the grain properties (their abundance, chemical composition and size d ...
ASTR 001 Introduction to the Cosmos
... D) Impossible to say, because Hubble’s constant has no relationship to the age of the universe. 14. Why do we believe 90 percent of the mass of the Milky Way is in the form of dark matter? A) The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars ...
... D) Impossible to say, because Hubble’s constant has no relationship to the age of the universe. 14. Why do we believe 90 percent of the mass of the Milky Way is in the form of dark matter? A) The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars ...
Dark Energy: how the paradigm shifted
... had been accumulating since 1932, when Jan Oort realized that the stars in the Milky Way are moving too fast to be held within the galaxy if the gravitational pull comes only from the visible matter. (At about the same time, Fritz Zwicky also found evidence for exotic hidden matter within clusters o ...
... had been accumulating since 1932, when Jan Oort realized that the stars in the Milky Way are moving too fast to be held within the galaxy if the gravitational pull comes only from the visible matter. (At about the same time, Fritz Zwicky also found evidence for exotic hidden matter within clusters o ...
EPB_Paper1_EarlyUniverse
... they formed later after the big bang, therefore these elements were more abundant in the universe. However, hydrogen and helium are still by far the most abundant gases found in population I stars [9]. The initial generations were formed in galaxies of very low mass, but the generations that formed ...
... they formed later after the big bang, therefore these elements were more abundant in the universe. However, hydrogen and helium are still by far the most abundant gases found in population I stars [9]. The initial generations were formed in galaxies of very low mass, but the generations that formed ...
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.