Quasars
... • AGNs turn `on´ and `off´ depending on the available matter • When all surrounding matter is exhausted, the AGN becomes invisible and its host a `normal´ galaxy • AGNs were more numerous in the past • The Milky Way may have experienced a (rather mild) AGN phase in the past Illustration of a black h ...
... • AGNs turn `on´ and `off´ depending on the available matter • When all surrounding matter is exhausted, the AGN becomes invisible and its host a `normal´ galaxy • AGNs were more numerous in the past • The Milky Way may have experienced a (rather mild) AGN phase in the past Illustration of a black h ...
Chapter 19. Mapping the Universe from Herschel to Sloan
... stars. Galaxies were giant collections of stars, gas and dust and to understand how matter was distributed through space, we had to focus on their distribution. Since faint galaxies could be seen right to the limit of the largest telescopes, it became clear that the Universe was much larger than we ...
... stars. Galaxies were giant collections of stars, gas and dust and to understand how matter was distributed through space, we had to focus on their distribution. Since faint galaxies could be seen right to the limit of the largest telescopes, it became clear that the Universe was much larger than we ...
P2 Revision Document 2013
... When answering a QWC question remember the following points: Use correct science vocabulary, organise ideas, avoid using “it”, and write in full sentences. You also need to try and keep you answer relevant to the question. A good way to do all this is to write out important key vocabulary and then u ...
... When answering a QWC question remember the following points: Use correct science vocabulary, organise ideas, avoid using “it”, and write in full sentences. You also need to try and keep you answer relevant to the question. A good way to do all this is to write out important key vocabulary and then u ...
Lecture 2: A Modern View of the Universe
... Example: • This photo shows the Andromeda Galaxy as it ...
... Example: • This photo shows the Andromeda Galaxy as it ...
Astronomy Essay Questions
... Describe and discuss neutron stars and pulsars. What are they and how are the related to each other? Describe their physical characteristics. How are they observed? Where do they fit into the process of stellar evolution? Describe and discuss neutron stars. What are they? Describe their physical ch ...
... Describe and discuss neutron stars and pulsars. What are they and how are the related to each other? Describe their physical characteristics. How are they observed? Where do they fit into the process of stellar evolution? Describe and discuss neutron stars. What are they? Describe their physical ch ...
Self-avoiding Random Walks and Olbers` Paradox - Serval
... stars is finite and is much too small to completely cover our celestial sphere [12, 14]. In fact Olbers’ paradox is frequently used as a proof against a static steady state infinite model of the Universe [14]. Halley’s reasoning was based on an intuitive assumption that stars are distributed uniformly ...
... stars is finite and is much too small to completely cover our celestial sphere [12, 14]. In fact Olbers’ paradox is frequently used as a proof against a static steady state infinite model of the Universe [14]. Halley’s reasoning was based on an intuitive assumption that stars are distributed uniformly ...
Lecture 7
... bubble-like or “frothy” structure. The pattern of superclusters, walls, and voids is called large-scale structure (LSS). On still larger scales, the Universe seems to be uniform. The “end of greatness” has been reached. 4) Galaxies, groups, clusters, walls, and superclusters all formed from gravity ...
... bubble-like or “frothy” structure. The pattern of superclusters, walls, and voids is called large-scale structure (LSS). On still larger scales, the Universe seems to be uniform. The “end of greatness” has been reached. 4) Galaxies, groups, clusters, walls, and superclusters all formed from gravity ...
Relativity with a Quantum Field
... the observer or relative to the undetectable preferred frame. The quantum field Quantum mechanics and the uncertainty principle require the existence of a quantum field of virtual particles surrounding all matter and energy(8). Unlike the field surrounding electrons the field around neutral particle ...
... the observer or relative to the undetectable preferred frame. The quantum field Quantum mechanics and the uncertainty principle require the existence of a quantum field of virtual particles surrounding all matter and energy(8). Unlike the field surrounding electrons the field around neutral particle ...
Powerpoint - UIUC HEP Group
... An optics industry developed in the late 16th century, led by the Dutch. Spectacles (one lens in front of each eye) were used as reading aids. The invention of the two-lens combination is a bit obscure, but Hans Lippershey’s binoculars were shown to the Dutch army in 1608. This was initially treated ...
... An optics industry developed in the late 16th century, led by the Dutch. Spectacles (one lens in front of each eye) were used as reading aids. The invention of the two-lens combination is a bit obscure, but Hans Lippershey’s binoculars were shown to the Dutch army in 1608. This was initially treated ...
A Tale of Two Physics
... This begat a round of errors starting by misreading the nature of dark energy which then led physicists to grossly understate the age of the universe by linearly extrapolating the Hubble constant backwards from what we now know to be a curve that can exhibit accelerated acceleration as it does now. ...
... This begat a round of errors starting by misreading the nature of dark energy which then led physicists to grossly understate the age of the universe by linearly extrapolating the Hubble constant backwards from what we now know to be a curve that can exhibit accelerated acceleration as it does now. ...
Ellipticity, Its Origin and Progression in Comoving Galaxies
... universe, contrary to Academia’s long-held view, is not expanding. Furthermore, the new-cosmology argument includes incontrovertible proof that our Cosmos is intrinsically cellularly structured, contrary to the view of mere phenomenological cellularity. A remarkable 2009 paper [6] entitled, “The Sto ...
... universe, contrary to Academia’s long-held view, is not expanding. Furthermore, the new-cosmology argument includes incontrovertible proof that our Cosmos is intrinsically cellularly structured, contrary to the view of mere phenomenological cellularity. A remarkable 2009 paper [6] entitled, “The Sto ...
Gravitational Lenses and Unconventional Gravity Theories
... bending predicted by general relativity for the mass of visible and hitherto undetected matter (but excluding the scalar field’s energy). Thus use of general relativity to interpret gravitational lensing observations can only underestimate the mass present in stars, gas and dark matter. The same con ...
... bending predicted by general relativity for the mass of visible and hitherto undetected matter (but excluding the scalar field’s energy). Thus use of general relativity to interpret gravitational lensing observations can only underestimate the mass present in stars, gas and dark matter. The same con ...
Lecture 1a
... A. Because no galaxies exist at such a great distance. B. Galaxies may exist at that distance, but their light would be too faint for our telescopes to see. C. Because looking 15 billion light-years away means looking to a time before the universe existed. © 2005 Pearson Education Inc., publishing a ...
... A. Because no galaxies exist at such a great distance. B. Galaxies may exist at that distance, but their light would be too faint for our telescopes to see. C. Because looking 15 billion light-years away means looking to a time before the universe existed. © 2005 Pearson Education Inc., publishing a ...
Finding the Most Distant Quasars Using Bayesian Selection Methods
... been almost completely ionised, as the first generations of stars—and quasars—emitted sufficient ultraviolet radiation to separate electrons from protons. The rest-frame wavelength of the break is at 0.1216 µm, but the wavelength of all light is increased by the cosmological expansion; the Universe ...
... been almost completely ionised, as the first generations of stars—and quasars—emitted sufficient ultraviolet radiation to separate electrons from protons. The rest-frame wavelength of the break is at 0.1216 µm, but the wavelength of all light is increased by the cosmological expansion; the Universe ...
PDF - at www.arxiv.org.
... is true, this represents a challenge to the dark matter hypothesis. While it is certainly conceivable that the success of Milgram’s empirical relation (7,8,9) might be explained by a dark matter model, that model would have to explain, 1. Why is the scatter in the Tully Fisher relation smaller when ...
... is true, this represents a challenge to the dark matter hypothesis. While it is certainly conceivable that the success of Milgram’s empirical relation (7,8,9) might be explained by a dark matter model, that model would have to explain, 1. Why is the scatter in the Tully Fisher relation smaller when ...
A Direct Empirical Proof of the Existence of Dark Matter
... itational force law (Zwicky 1937). Proposed solutions either invoke dominant quantities of non-luminous “dark matter” (Oort 1932) or alterations to either the gravita tional force law (Bekenstein 2004; Brownstein & Moffat 2006) or the particles’ dynamical response to it (Mil grom 1983). Previous wo ...
... itational force law (Zwicky 1937). Proposed solutions either invoke dominant quantities of non-luminous “dark matter” (Oort 1932) or alterations to either the gravita tional force law (Bekenstein 2004; Brownstein & Moffat 2006) or the particles’ dynamical response to it (Mil grom 1983). Previous wo ...
Four Big Questions With Pretty Good Answers
... That a question makes grammatical sense does not guarantee that it is answerable, or even coherent. Indeed, this observation is a central theme of Heisenberg’s early, classic exposition of quantum theory [1]. In that spirit, let us begin with a critical examination of the question posed in this Sect ...
... That a question makes grammatical sense does not guarantee that it is answerable, or even coherent. Indeed, this observation is a central theme of Heisenberg’s early, classic exposition of quantum theory [1]. In that spirit, let us begin with a critical examination of the question posed in this Sect ...
Astrophysics Questions (DRAFT)
... 94. Sketch a typical cooling function (T ) for diuse interstellar gas and identify its prominent features. Overplot a hypothetical heating curve and show how to identify points of thermal equilibrium and their stability. 95. Explain the physics of 21 cm radio emission from neutral hydrogen atoms. ...
... 94. Sketch a typical cooling function (T ) for diuse interstellar gas and identify its prominent features. Overplot a hypothetical heating curve and show how to identify points of thermal equilibrium and their stability. 95. Explain the physics of 21 cm radio emission from neutral hydrogen atoms. ...
Velocity dispersion around ellipticals in MOND
... Measuring the velocity field in and around galaxies is the main way to test the dark matter distribution at small and intermediate scales. The observation of what are apparently non-Newtonian rotation curves around spiral galaxies (e.g. Rubin et al. 1980) has been first solved by assuming that galax ...
... Measuring the velocity field in and around galaxies is the main way to test the dark matter distribution at small and intermediate scales. The observation of what are apparently non-Newtonian rotation curves around spiral galaxies (e.g. Rubin et al. 1980) has been first solved by assuming that galax ...
Supernovae and cosmology
... Weight more than Chandrasekar limit Core collapses Pressure increases on gas surrounding core Potential energy is released as heat ...
... Weight more than Chandrasekar limit Core collapses Pressure increases on gas surrounding core Potential energy is released as heat ...
Gamma-ray absorption and pair echos at very high
... to the most powerful known blazars such as 3C279 with apparent GeV luminosities L ∼ 1048 erg s−1 should be firmly detectable by Fermi out to z ∼ 8 − 10 if they exist [17]. Utilizing the blazar evolution model of [18] which is consistent with the observed statistics of the blazar population and takes ...
... to the most powerful known blazars such as 3C279 with apparent GeV luminosities L ∼ 1048 erg s−1 should be firmly detectable by Fermi out to z ∼ 8 − 10 if they exist [17]. Utilizing the blazar evolution model of [18] which is consistent with the observed statistics of the blazar population and takes ...
Non-standard cosmology
A non-standard cosmology is any physical cosmological model of the universe that has been, or still is, proposed as an alternative to the Big Bang model of standard physical cosmology. In the history of cosmology, various scientists and researchers have disputed parts or all of the Big Bang due to a rejection or addition of fundamental assumptions needed to develop a theoretical model of the universe. From the 1940s to the 1960s, the astrophysical community was equally divided between supporters of the Big Bang theory and supporters of a rival steady state universe. It was not until advances in observational cosmology in the late 1960s that the Big Bang would eventually become the dominant theory, and today there are few active researchers who dispute it.The term non-standard is applied to any cosmological theory that does not conform to the scientific consensus, but is not used in describing alternative models where no consensus has been reached, and is also used to describe theories that accept a ""big bang"" occurred but differ as to the detailed physics of the origin and evolution of the universe. Because the term depends on the prevailing consensus, the meaning of the term changes over time. For example, hot dark matter would not have been considered non-standard in 1990, but would be in 2010. Conversely, a non-zero cosmological constant resulting in an accelerating universe would have been considered non-standard in 1990, but is part of the standard cosmology in 2010.