High velocity clouds (v > 90 km/s), up to 108 M_sun in total Seen at
... This is how V should fall off with r as long as all of the mass is interior to the orbits being considered. Now, consider a spherical distribution of mass of uniform density, in which particles (stars) orbit inside the mass distribution. The mass interior to the orbit is then ! ...
... This is how V should fall off with r as long as all of the mass is interior to the orbits being considered. Now, consider a spherical distribution of mass of uniform density, in which particles (stars) orbit inside the mass distribution. The mass interior to the orbit is then ! ...
Cosmology and Astrophysics II
... The helium-4 abundance is important because there is far more helium-4 in the universe than can be explained by stellar nucleosynthesis. In addition, it provides an important test for the Big Bang theory. If the observed helium abundance is much different from 25%, then this would pose a serious cha ...
... The helium-4 abundance is important because there is far more helium-4 in the universe than can be explained by stellar nucleosynthesis. In addition, it provides an important test for the Big Bang theory. If the observed helium abundance is much different from 25%, then this would pose a serious cha ...
Physics 127 Descriptive Astronomy Homework #20 Key
... 14-3. How did Edwin Hubble prove that the Andromeda “Nebula” is not a nebula within our Milky Way Galaxy? Hubble was able to detect Cepheid variable stars within that “Nebula.” Then by observing their light curves and using the known period- luminosity relation for Cepheids, he obtained and compared ...
... 14-3. How did Edwin Hubble prove that the Andromeda “Nebula” is not a nebula within our Milky Way Galaxy? Hubble was able to detect Cepheid variable stars within that “Nebula.” Then by observing their light curves and using the known period- luminosity relation for Cepheids, he obtained and compared ...
The Particle Adventure go to: http://www.particleadventure.org
... move to the next page the backward arrow to go back to review. The page summary at the left of the screen highlights your current page so you can keep track of where you are. 1. What is the basic question the particle adventure tries to answer? ...
... move to the next page the backward arrow to go back to review. The page summary at the left of the screen highlights your current page so you can keep track of where you are. 1. What is the basic question the particle adventure tries to answer? ...
Dark Matter Concept Questions
... 6. Do your results support the following statement? “It is reasonable to expect that stars orbit around the gravitational mass contained within the radius of their orbit in the same way that planets orbit around the Sun.” Discuss. 7. Explain the shape of your plot for measured speed against orbital ...
... 6. Do your results support the following statement? “It is reasonable to expect that stars orbit around the gravitational mass contained within the radius of their orbit in the same way that planets orbit around the Sun.” Discuss. 7. Explain the shape of your plot for measured speed against orbital ...
Galaxies - sciencejedi.com
... • There were arguments and observations on both sides, but little movement toward a consensus. The nature of this scientific conflict has passed into the folklore of astronomy, and has been embodied by a public scientific debate known as the Shapley-Curtis Debate, or simply The Great Debate. • The ...
... • There were arguments and observations on both sides, but little movement toward a consensus. The nature of this scientific conflict has passed into the folklore of astronomy, and has been embodied by a public scientific debate known as the Shapley-Curtis Debate, or simply The Great Debate. • The ...
T Einstein’s Mirage Paul L. Schechter
... being imaged—it is a mirror image, but distorted. At least one of the other images must have the correct handedness, but it will also be distorted. The French call such distorted images gravitational mirages. In the half century following the confirmation of general relativity, the idea that cosmic ...
... being imaged—it is a mirror image, but distorted. At least one of the other images must have the correct handedness, but it will also be distorted. The French call such distorted images gravitational mirages. In the half century following the confirmation of general relativity, the idea that cosmic ...
The Constant-Sound-Speed parameterization of the quark matter EoS
... sufficiently heavy neutron stars may really be “hybrid stars” with quark matter cores. Since little is known about the quark matter equation of state, we perform a model-independent study of the form of the mass-radius relation for hybrid stars, making only some generic assumptions about the quark m ...
... sufficiently heavy neutron stars may really be “hybrid stars” with quark matter cores. Since little is known about the quark matter equation of state, we perform a model-independent study of the form of the mass-radius relation for hybrid stars, making only some generic assumptions about the quark m ...
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.