Lecture notes 18: Galaxies and galaxy clusters
... Gravitational lenses and dark matter. Galactic cluster dynamics show that there is a great amount of dark matter: there is not enough luminous matter, even when considering the very hot intergalactic gas clouds, to bind galaxies together. Another method of assessing the mass of galaxy clusters is by ...
... Gravitational lenses and dark matter. Galactic cluster dynamics show that there is a great amount of dark matter: there is not enough luminous matter, even when considering the very hot intergalactic gas clouds, to bind galaxies together. Another method of assessing the mass of galaxy clusters is by ...
2. The World at Large: From the Big Bang to Black Holes
... We measure distances by the time it takes for light to traverse them. The velocity of light is about 300,000 km s−1 . From the Moon to the Earth (384,000 km) the light needs a little more than a second (1.28 s), from the Sun to the Earth about 8 min. Thus we say that the Earth–Sun distance is 8 ligh ...
... We measure distances by the time it takes for light to traverse them. The velocity of light is about 300,000 km s−1 . From the Moon to the Earth (384,000 km) the light needs a little more than a second (1.28 s), from the Sun to the Earth about 8 min. Thus we say that the Earth–Sun distance is 8 ligh ...
Galaxy Classification Much of modern extragalactic astronomy deals
... In this method, supergiant galaxies with well-developed bright spiral arms and bars have the Roman numeral I (like supergiant stars), and small, low-surface-brightness, irregular galaxies have the roman numeral V. Of course, since one doesn’t usually know a galaxy’s distance, it is somewhat difficul ...
... In this method, supergiant galaxies with well-developed bright spiral arms and bars have the Roman numeral I (like supergiant stars), and small, low-surface-brightness, irregular galaxies have the roman numeral V. Of course, since one doesn’t usually know a galaxy’s distance, it is somewhat difficul ...
Galaxy Powerpoint Notes
... name ‘irregular’. They are very uncommon within our universe though they are believed to once be spiral or elliptical galaxies that were altered by a gravitational pull. Irregular galaxies contain an abundant amount of gas and dust. Examples of irregular galaxies include Whirlpool Galaxy, Hoag’s Gal ...
... name ‘irregular’. They are very uncommon within our universe though they are believed to once be spiral or elliptical galaxies that were altered by a gravitational pull. Irregular galaxies contain an abundant amount of gas and dust. Examples of irregular galaxies include Whirlpool Galaxy, Hoag’s Gal ...
PDF format
... fundamental forces are aspects of a more general force that became separate ("froze out") during the big bang? a) It can't be tested. b) They study far-away objects to see how forces behave at times early in the universe. c) Particle accelerators like Fermilab and the Large Hadron Collider have t ...
... fundamental forces are aspects of a more general force that became separate ("froze out") during the big bang? a) It can't be tested. b) They study far-away objects to see how forces behave at times early in the universe. c) Particle accelerators like Fermilab and the Large Hadron Collider have t ...
A dearth of dark matter in strong gravitational lenses
... Here I have selected 65 objects from their sample. These are lenses which are classified as elliptical galaxies, and which have complete photometric data, all with estimates of the stellar mass. In the dynamical analysis, I assume that the total light and mass distribution is given by the spherical ...
... Here I have selected 65 objects from their sample. These are lenses which are classified as elliptical galaxies, and which have complete photometric data, all with estimates of the stellar mass. In the dynamical analysis, I assume that the total light and mass distribution is given by the spherical ...
Galaxies on Sub-Galactic Scales
... et al. 1999, Diemand et al. 2005). If these subhalos have accumulated sufficient primordial hydrogen gas and turned it into stars like their more massive brethren they should be visible as small Milky Way satellite galaxies today. However, there were only eleven. Taking these numbers from computer s ...
... et al. 1999, Diemand et al. 2005). If these subhalos have accumulated sufficient primordial hydrogen gas and turned it into stars like their more massive brethren they should be visible as small Milky Way satellite galaxies today. However, there were only eleven. Taking these numbers from computer s ...
lesson plan document only
... Do scientists really know what dark matter is? Can you see dark matter? Why or why not? What is a W.I.M.P.? What does W.I.M.P.’s stand for? How much Dark Matter is in the universe? Have scientists been able to detect Dark Matter? What does gravity do to matter? When scientists analyze distant galaxi ...
... Do scientists really know what dark matter is? Can you see dark matter? Why or why not? What is a W.I.M.P.? What does W.I.M.P.’s stand for? How much Dark Matter is in the universe? Have scientists been able to detect Dark Matter? What does gravity do to matter? When scientists analyze distant galaxi ...
UNIT 4 - Galaxies XIV. The Milky Way A. Structure
... there are three types of active galaxies: Seyfert Galaxies, Radio Galaxies, and Quasars active galaxies look like normal galaxies but emit enormous amounts of radio/infrared radiation ...
... there are three types of active galaxies: Seyfert Galaxies, Radio Galaxies, and Quasars active galaxies look like normal galaxies but emit enormous amounts of radio/infrared radiation ...
Galaxies - University of Iowa Astrophysics
... 1. Measure the distance to star A to be 200 pc. 2. Measure the flux of star A. 3. Measure the flux of star B, which is known to have the same luminosity as star A, to be lower by a factor of 1600 (or the flux of A is 1600 times the flux of B). 4. Find the distance to star B. ...
... 1. Measure the distance to star A to be 200 pc. 2. Measure the flux of star A. 3. Measure the flux of star B, which is known to have the same luminosity as star A, to be lower by a factor of 1600 (or the flux of A is 1600 times the flux of B). 4. Find the distance to star B. ...
Lecture 5: Physics Beyond the Standard Model and Supersymmetry
... • Why do we need physics beyond the Standard Model? • The Standard Model does not describe gravity • Hints of Grand Unification • Two more issues that we discuss in detail • Dark Matter • ’Hierarchy problem’ Dark Matter • Stars at the edges of galaxies are moving too fast • Cannot be explained from ...
... • Why do we need physics beyond the Standard Model? • The Standard Model does not describe gravity • Hints of Grand Unification • Two more issues that we discuss in detail • Dark Matter • ’Hierarchy problem’ Dark Matter • Stars at the edges of galaxies are moving too fast • Cannot be explained from ...
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.