Wheeler–Feynman absorber theory The Wheeler–Feynman absorber theory (also called the Wheeler–Feynman time-symmetric theory) is an interpretation of electrodynamics derived from the assumption that the solutions of the electromagnetic field equations must be invariant under time-reversal symmetry, as are the field equations themselves. Indeed, there is no apparent reason for the time-reversal symmetry breaking which singles out a preferential time direction and thus makes a distinction between past and future. A time-reversal invariant theory is more logical and elegant. Another key principle, resulting from this interpretation and reminiscent of Mach's principle due to Tetrode, is that elementary particles are not self-interacting. This theory is named after its originators, the late physicists Richard Feynman and John Archibald Wheeler. T-symmetry and causality[edit] and point , which will arrive at point at the instant (here Feynman and Wheeler obtained this result in a very simple and elegant way. holds, ) is then: T. and
Summary of Hegel's Philosophy of Mind Up to the English Server! Paul Trejo, August 1993 For over 180 years students have complained that Hegel's best-known book of philosophy, the PHENOMENOLOGY OF MIND (alias PHENOMENOLOGY OF SPIRIT), is too difficult to read. A few have tried to summarize Hegel's book, and often their summaries were longer than the original, and just as difficult to read. Today, right here on the INTERNET, I give to you a twelve page summary of this famous book, a book that inspired generations of European philosophers since it first appeared in 1807. This summary is meant for the beginner in phenomenological philosophy, to encourage more students to struggle with the book for themselves. This book has a colorful history, and is well praised by thinkers as David Strauss, Bruno Bauer, Marx, Engels, Ortega y Gasset, Jean-Paul Sartre, Simone de Beauvoir, Lacan, Camus, and many more.
What does the Universe look like as seen from its most distant galaxy? “One sees qualities at a distance and defects at close range.” -Victor Hugo A couple of weeks ago we took a look at the most distant galaxy (so far) in the known Universe, a galaxy so far away that it takes exclusively infrared observations from our most power space telescopes (Hubble and Spitzer) in order to detect it. What’s perhaps even more remarkable is that the light we do detect from it — the light we detected in the infrared — was actually emitted in the Ultraviolet part of the spectrum! Image credit: NASA, ESA, Garth Illingworth (University of California, Santa Cruz) and Rychard Bouwens (University of California, Santa Cruz and Leiden University) and the HUDF09 Team. It’s only the vast expansion-and-redshift of the Universe that has taken place, along with the fact that the light has been traveling for some 13.4 billion years, that allow us to observe it as we do. Image credit: Dave Morrow, ©2013 OneBigPhoto.com. Image credit: Richard Powell of
Comoving distance Comoving coordinates[edit] While general relativity allows one to formulate the laws of physics using arbitrary coordinates, some coordinate choices are more natural (easier to work with). Comoving coordinates are an example of such a natural coordinate choice. They assign constant spatial coordinate values to observers who perceive the universe as isotropic. Such observers are called "comoving" observers because they move along with the Hubble flow. A comoving observer is the only observer that will perceive the universe, including the cosmic microwave background radiation, to be isotropic. Most large lumps of matter, such as galaxies, are nearly comoving, so that their peculiar velocities (owing to gravitational attraction) are low. The comoving time coordinate is the elapsed time since the Big Bang according to a clock of a comoving observer and is a measure of cosmological time. See also: metric expansion of space. Comoving distance and proper distance[edit] Definitions is related to by
Jean Baudrillard Jean Baudrillard (/ˌboʊdriːˈɑr/;[1] French: [ʒɑ̃ bodʁijaʁ]; 27 July 1929 – 6 March 2007) was a French sociologist, philosopher, cultural theorist, political commentator, and photographer. His work is frequently associated with postmodernism and specifically post-structuralism. Life[edit] Baudrillard was born in Reims, northeastern France, on 27 July 1929. While teaching German, Baudrillard began to transfer to sociology, eventually completing his doctoral thesis Le Système des objets (The System of Objects) under the dissertation committee of Henri Lefebvre, Roland Barthes, and Pierre Bourdieu. In 1970, Baudrillard made the first of his many trips to the United States (Aspen, Colorado), and in 1973, the first of several trips to Kyoto, Japan. In 1986 he moved to IRIS (Institut de Recherche et d'Information Socio-Économique) at the Université de Paris-IX Dauphine, where he spent the latter part of his teaching career. Core ideas[edit] The object value system[edit] [edit] Reception[edit]
Goodbye Big Bang, Hello Black Hole? A New Theory Of The Universe’s Creation Want to stay on top of all the space news? Follow @universetoday on Twitter Artist’s conception of the event horizon of a black hole. Credit: Victor de Schwanberg/Science Photo Library Could the famed “Big Bang” theory need a revision? Before getting into their findings, let’s just preface this by saying nobody knows anything for sure. “For all physicists know, dragons could have come flying out of the singularity,” stated Niayesh Afshordi, an astrophysicist with the Perimeter Institute for Theoretical Physics in Canada who co-authored the new study. So what are the limitations of the Big Bang theory? Most cosmologists say the universe must have been expanding faster than the speed of light for this to happen, but Ashford says even that theory has problems: “The Big Bang was so chaotic, it’s not clear there would have been even a small homogenous patch for inflation to start working on.” This is what the physicists propose: The long and the short of it? Source: Nature About Elizabeth Howell
The Ultimate Laptop: A Black Hole New York Times, September 5, 2000 By GEORGE JOHNSON For all the corporate enthusiasm over the unveiling of each new generation of computer chip (last month Intel announced that its Pentium 4 would be packed with 42 million transistors performing as many as 8.4 billion operations per second), consumers may be more apt to feel a sense of dread. Once again the expensive desktop computers and laptops they were so proud of have become outmoded, destined to join the scrap piles of unsalable equipment accumulating in closets everywhere. Moore's law, which holds that computing power doubles approximately every 18 months, sometimes seems less a blessing than a curse. In a paper in the current issue of Nature, Dr. If that sounds like a rather dangerous device to hold on one's lap -- "Opening the lid," Dr. Nothing like Lloyd's Ultimate Laptop is likely to roll off the assembly line at some future Apple or I.B.M. Thomas J. But ultimately the limits of nature must prevail. Dr. Here Dr.
Kant's Transcendental Arguments (Stanford Encyclopedia of Philosophy) 1. The Transcendental Deduction The Transcendental Deduction (A84–130, B116–169) is Kant’s attempt to demonstrate against empiricist psychological theory that certain a priori concepts correctly apply to objects featured in our experience. Dieter Henrich (1989) points out that Kant’s use of ‘Deduktion’ redeploys German legal vocabulary; in Holy Roman Empire Law, ‘Deduktion’ signifies an argument intended to yield a historical justification for the legitimacy of a property claim. In Kant’s derivative epistemological sense, a deduction is an argument that aims to justify the use of a concept, one that demonstrates that the concept correctly applies to objects. David Hume in effect denies that a deduction can be provided for a number of metaphysical concepts – ideas, in his terminology – including the ideas of personal identity, of identity over time more generally, of the self as a subject distinct from its perceptions, and of causal power or force (1739, 1748). 2. Note 3. 3. and 4. 5.
The Strangest Black Holes in the Universe Credit: Alain R. | Wikimedia CommonsBlack holes are gigantic cosmic monsters, exotic objects whose gravity is so strong that not even light can escape their clutches. Black holes come in a wide variety of forms, from small stellar-mass bodies to the supermassive beasts that reside at the hearts of galaxies. Here are 10 of the most extreme black holes, from the smallest to the largest and from cannibals to rogues. FIRST UP: The biggest and baddest Why Our Universe Must Have Been Born Inside a Black Hole “Accordingly, our own Universe may be the interior of a black hole existing in another universe.” So concludes Nikodem Poplawski at Indiana University in a remarkable paper about the nature of space and the origin of time. The idea that new universes can be created inside black holes and that our own may have originated in this way has been the raw fodder of science fiction for many years. Today Poplawski provides such a derivation. Poplawski points out that the standard derivation of general relativity takes no account of the intrinsic momentum of spin half particles. This predicts that particles with half integer spin should interact, generating a tiny repulsive force called torsion. That’s interesting for a number of reasons. Astrophysicists have long known that our universe is so big that it could not have reached its current size given the rate of expansion we see now. The problem with inflation is that it needs an additional theory to explain why it occurs and that’s ugly.
Practicing The Subtle Art Of Detachment – Personal Growth – Medium From everything that I recall about my life so far, I can say one thing with absolute certainty. I have been an extremely passionate person. Passionate about everything. I take the leap and I go all in like there is no middle spot. And that always seemed to work for me. Until, I reached a day when the things that really mattered to me were at a point of collapse and I collapsed along with them. And my story is not really unique in this sense. Mental fatigue and burnout is almost like the epidemic of the century. And that’s because there is a bit of a downside of being too passionate. And why is that? Because with attachment comes a very strong urge to control the circumstances. While you can exercise some amount of control over what happens in your life, that will absolutely never eliminate the possibility of things going haywire or the possibility of your plans and ambitions not quite turning into reality. And I don’t deny that this kind of confidence is necessary. I don’t think so. 2. 3. 4.