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... universe was much more active in the past (z ~1 - 2) but what happens earlier is unclear There are many complications of interpretation, including the reliability of each SFR ...
... universe was much more active in the past (z ~1 - 2) but what happens earlier is unclear There are many complications of interpretation, including the reliability of each SFR ...
The Milky Way Galaxy
... Galaxies can usefully be considered to be made up of two components: a spheroid and a disc (Figure 1). The spheroid is made up of stars that move around in a disorganized way, rather like a swarm of bees. Its name derives from its only moderately nonspherical shape. The disc is a highly flattened st ...
... Galaxies can usefully be considered to be made up of two components: a spheroid and a disc (Figure 1). The spheroid is made up of stars that move around in a disorganized way, rather like a swarm of bees. Its name derives from its only moderately nonspherical shape. The disc is a highly flattened st ...
Axiom Cosmology: A New Direction
... rem in general relativity demonstrated—sixty years after its discovery—that Einstein’s theory was consistent and stable [5] [6]. Most modern, accepted theories of cosmology are based on general relativity and, more specifically, the predicted Big Bang [7] [8]. In the universe, the axiom field repres ...
... rem in general relativity demonstrated—sixty years after its discovery—that Einstein’s theory was consistent and stable [5] [6]. Most modern, accepted theories of cosmology are based on general relativity and, more specifically, the predicted Big Bang [7] [8]. In the universe, the axiom field repres ...
Supplemental Educational Support Materials
... The attractive force between all masses in the universe. All objects that have mass possess a gravitational force that attracts all other masses. The more massive the object, the stronger the gravitational force. The closer objects are to each other, the stronger the gravitational attraction. ...
... The attractive force between all masses in the universe. All objects that have mass possess a gravitational force that attracts all other masses. The more massive the object, the stronger the gravitational force. The closer objects are to each other, the stronger the gravitational attraction. ...
AS 4022: Cosmology - ASTRONOMY GROUP – University of St
... – moving in a slow dance around the center of galaxies. ...
... – moving in a slow dance around the center of galaxies. ...
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.