Extremal Black holes and the limits of the third law
... For a black hole with mass M, charge Q and specific angular momentum a, the temperature is proportional to the surface gravity κ ∝ (M 2 −Q2 −a2 )1/2 , and the entropy, according to the Bekenstein-Hawking formula, is simply one-fourth the area of the event horizon. Clearly, the temperature vanishes w ...
... For a black hole with mass M, charge Q and specific angular momentum a, the temperature is proportional to the surface gravity κ ∝ (M 2 −Q2 −a2 )1/2 , and the entropy, according to the Bekenstein-Hawking formula, is simply one-fourth the area of the event horizon. Clearly, the temperature vanishes w ...
Black Holes
... This distance is so small, that at this level of precision, LIGO’s moving mirrors are governed not by the laws of classical physics, but rather by the laws of quantum physics. For example, the Heisenberg uncertainty principle dictates that the very act of measuring the location of a 40 kilogram mirr ...
... This distance is so small, that at this level of precision, LIGO’s moving mirrors are governed not by the laws of classical physics, but rather by the laws of quantum physics. For example, the Heisenberg uncertainty principle dictates that the very act of measuring the location of a 40 kilogram mirr ...
Black Hole Spacetimes
... They both have intuitive physical meanings. However, inside r = 2M , both gtt and grr change signs. That means r is a time coordinate, and t is now a space coordinate. No observer (massive or massless) can stand still in time. Therefore, if a geodesic (time-like or null) crosses the surface r = 2M f ...
... They both have intuitive physical meanings. However, inside r = 2M , both gtt and grr change signs. That means r is a time coordinate, and t is now a space coordinate. No observer (massive or massless) can stand still in time. Therefore, if a geodesic (time-like or null) crosses the surface r = 2M f ...
Strings and Black Holes
... Conjecture: large N SU(N) gauge theory with 16 SUSY’s is dual to string theory in a background that is anti-de Sitter space X sphere Need to take ‘t Hooft limit N , GN fixed, but large Dimensional analysis Get Bekenstein-Hawking entropy right to within an overall factor To do better requires ...
... Conjecture: large N SU(N) gauge theory with 16 SUSY’s is dual to string theory in a background that is anti-de Sitter space X sphere Need to take ‘t Hooft limit N , GN fixed, but large Dimensional analysis Get Bekenstein-Hawking entropy right to within an overall factor To do better requires ...
White Dwarfs - University of Maryland Astronomy
... fast because core’s spin speeds up as it collapses into neutron star. ...
... fast because core’s spin speeds up as it collapses into neutron star. ...
Quantum Gravity - General overview and recent developments
... External time t has vanished from the formalism This holds also for loop quantum gravity and probably for string theory Wheeler–DeWitt equation has the structure of a wave equation any may therefore allow the introduction of an “intrinsic time” Hilbert-space structure in quantum mechanics is connect ...
... External time t has vanished from the formalism This holds also for loop quantum gravity and probably for string theory Wheeler–DeWitt equation has the structure of a wave equation any may therefore allow the introduction of an “intrinsic time” Hilbert-space structure in quantum mechanics is connect ...
Stellar Evolution after the Main Sequence
... • After the He core becomes substantial, then things begin to happen differently. • The star heats and compresses faster, the He doesn't get a chance to form the electron gas and so there is no He flash. • Instead, the He reaches the 100 million K needed to begin He C ...
... • After the He core becomes substantial, then things begin to happen differently. • The star heats and compresses faster, the He doesn't get a chance to form the electron gas and so there is no He flash. • Instead, the He reaches the 100 million K needed to begin He C ...
The dark heart of the Milky Way
... Andrea Ghez and her research colleagues used one of the twin telescopes of Keck Observatory on the summit of Mauna Kea in Hawaii. With their mirrors of nearly 10 metres in diameter, these are among the world’s largest telescopes today. Every mirror resembles a honeycomb, comprising 36 hexagonal segm ...
... Andrea Ghez and her research colleagues used one of the twin telescopes of Keck Observatory on the summit of Mauna Kea in Hawaii. With their mirrors of nearly 10 metres in diameter, these are among the world’s largest telescopes today. Every mirror resembles a honeycomb, comprising 36 hexagonal segm ...
Lecture 18
... d) Perhaps massive stars don’t form from one collapsing cloud, but instead form from collisions of smaller stars? Idea: stars today never collide, but collisions would be more frequent: • In young clusters where stars form, which are much denser than the Galaxy in the Solar neighborhood. • Young st ...
... d) Perhaps massive stars don’t form from one collapsing cloud, but instead form from collisions of smaller stars? Idea: stars today never collide, but collisions would be more frequent: • In young clusters where stars form, which are much denser than the Galaxy in the Solar neighborhood. • Young st ...
English Summary
... how we can relate these objects to ‘normal’ galaxies and more powerful, distant AGN like quasars (Chapter 5). Results show that the spatial distributions of nearby composite, LINER and Seyfert galaxies appear consistent with bright quasars being their progenitors. Finally, we have carried out severa ...
... how we can relate these objects to ‘normal’ galaxies and more powerful, distant AGN like quasars (Chapter 5). Results show that the spatial distributions of nearby composite, LINER and Seyfert galaxies appear consistent with bright quasars being their progenitors. Finally, we have carried out severa ...
The Nature of Time Travel
... In many science fiction books/movies one can often find the story of people traveling backward or forward in time Who among us has not seen “Back to the ...
... In many science fiction books/movies one can often find the story of people traveling backward or forward in time Who among us has not seen “Back to the ...
Powerpoint for today
... If core with about 3 MSun or more collapses, not even neutron pressure can stop it (total mass of star about 25 MSun). Core collapses to a point, a "singularity". Gravity is so strong that nothing can escape, not even light => black hole. Schwarzschild radius for Earth is 1 cm. For a 3 MSun object, ...
... If core with about 3 MSun or more collapses, not even neutron pressure can stop it (total mass of star about 25 MSun). Core collapses to a point, a "singularity". Gravity is so strong that nothing can escape, not even light => black hole. Schwarzschild radius for Earth is 1 cm. For a 3 MSun object, ...
Blackbody radiation Temperature of stars
... dependence, Stefan’s law, Wien’s law Statistical mechanics, Boltzmann distribution, equipartition law Cavity radiation, Rayleigh-Jeans classical formula ...
... dependence, Stefan’s law, Wien’s law Statistical mechanics, Boltzmann distribution, equipartition law Cavity radiation, Rayleigh-Jeans classical formula ...
Astronomy
... D. Applying the modified version of Kepler's 3rd law, if the black hole is in a binary system ...
... D. Applying the modified version of Kepler's 3rd law, if the black hole is in a binary system ...
Phys.Rev. D 90 (2014)
... Boson excitations can further lead to quantum depletion of the condensate out of the ground state. Such “leaking” of gravitons can be interpreted (at least in a first order approximation) as the emission of Hawking radiation. This kind of toy model is very intuitive and also gives an elegant quantum ...
... Boson excitations can further lead to quantum depletion of the condensate out of the ground state. Such “leaking” of gravitons can be interpreted (at least in a first order approximation) as the emission of Hawking radiation. This kind of toy model is very intuitive and also gives an elegant quantum ...
Physics 127 Descriptive Astronomy Homework #19 Key
... hydrogen clouds emit profuse amounts of visible light (see, for example, Figure 11-1). What causes this difference? To emit visible light, hydrogen must be at least partially ionized. This happens readily in the vicinity of O- and B-type stars which radiate copious numbers of ultraviolet photons, ma ...
... hydrogen clouds emit profuse amounts of visible light (see, for example, Figure 11-1). What causes this difference? To emit visible light, hydrogen must be at least partially ionized. This happens readily in the vicinity of O- and B-type stars which radiate copious numbers of ultraviolet photons, ma ...
fundamental_reality\holographic principle
... evolution of string theory provides a potential resolution of the conflict between gravity and quantum mechanics. It does this by proposing that all the information in the universe is located on the 2D quantum surface bounding the universe, which results in our holographic 3D universe in which the t ...
... evolution of string theory provides a potential resolution of the conflict between gravity and quantum mechanics. It does this by proposing that all the information in the universe is located on the 2D quantum surface bounding the universe, which results in our holographic 3D universe in which the t ...
Hawking radiation
Hawking radiation is black body radiation that is predicted to be released by black holes, due to quantum effects near the event horizon. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974, and sometimes also after Jacob Bekenstein, who predicted that black holes should have a finite, non-zero temperature and entropy.Hawking's work followed his visit to Moscow in 1973 where the Soviet scientists Yakov Zeldovich and Alexei Starobinsky showed him that, according to the quantum mechanical uncertainty principle, rotating black holes should create and emit particles. Hawking radiation reduces the mass and energy of black holes and is therefore also known as black hole evaporation. Because of this, black holes that lose more mass than they gain through other means are expected to shrink and ultimately vanish. Micro black holes are predicted to be larger net emitters of radiation than larger black holes and should shrink and dissipate faster.In September 2010, a signal that is closely related to black hole Hawking radiation (see analog gravity) was claimed to have been observed in a laboratory experiment involving optical light pulses. However, the results remain unverified and debatable. Other projects have been launched to look for this radiation within the framework of analog gravity. In June 2008, NASA launched the Fermi space telescope, which is searching for the terminal gamma-ray flashes expected from evaporating primordial black holes. In the event that speculative large extra dimension theories are correct, CERN's Large Hadron Collider may be able to create micro black holes and observe their evaporation.