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DrRocket

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Everything posted by DrRocket

  1. That makes two actual mathematicians providing the same answer.
  2. The dimension associated with time is in fact time, just as the dimension associated with space is distance. Time has nothing to do with "creating a 3-dimensional space". Moreover, in general relativity, coordinate systems are local, and there is no global distinction between time and space, only a 4-dimensional spacetime manifold. There is no such thing as a "10+1 dim space with a certain rate" and no sensible interpretation of what such a thing might be. Space doesn't have a rate.
  3. That will work. But the acceleration necessary to reach relativistic speed relative to the location of the detonation of the bomb in time to be effective will plrobably kill you. A single photon is a point particle. It has neither a front nor a back.
  4. Wrong on all counts. You obviously know as little about the history of systems theory as you know of the actual content. Kalman introduced state space methods and solved the linear quadratic Gaussian problem in the 1958-1962 time frame. Control theory is much older and arguably dates from the centrifugal governor for steam engines that was introduced in 1788 by James Watt. The theory of negative feedback systems goes back to Black's work in extending the bandwidth of amplifiers in 1927, and was used by Weiner in the development of classical frequency domain methods for sevomechanims and control of anti-aircraft guns. Synthesis across disciplines is as old as the subject itself. Synthesis across disciplines is the heart of not only general systems theory but even control theory, for the definition of that which is to be controlled is quite open. The general notion of a state space goes back at least to LaPlace and Lagrange, and perhaps even to my academic ancestor Isaac Newton with the invention of differential equations. See Jay Forester's work from the 1950's for an example of extreme multidisciplinarity. Yep. Your article has major inconsistencies and inaccuracies. Perhaps you should take the time, as I did, to study the subject for a few years in depth and refrain from writing about that which you do not understand until you have learned a bit more.
  5. It comes from understanding the subject. Any other mathematician would tell you the same thing.
  6. And per my post above, the answer is "no".
  7. Minkowski space is also flat. What need not be flat is spacetime which is a 4-dimensional Lorentzian manifold. It is the tangent space to spacetime that is Minkowski space. s² = (ct)²-x² describes the Lorentzian metric in local coordinates, independent of any curvature (any manifold is "locally flat"). It is also locally Euclidean if one looks at local "space" so it tells you nothing about whether orb not the Pythagorean theorem holds in the large --that requires knowledge of curvature. Cosmological models assume homogeneity and isotropy, which implies constant curvature. So in cosmological models space is the same everywhere. But that is true only as an approximation at the very largest scales, as ajb observed. Note that even the notion of b"space" and "time" at the global level requires homogeneity and isotropy. See this thread for more: http://www.scienceforums.net/topic/33180-cosmo-basics/ This has little to do with e=mc^2 in general. The importance of the equivalence of mass and energy to this context is the effect of mass/energy on curvature since curvature of spacetime is what we call gravity. The actual large-scale curvature of space is unknown and it is, under the assumption of isotropy and homogeneity, what determines the topology of space.
  8. This is relly a general relativity issue. You are comparing two clocks, one (in an earth orbit) essentially in free fall and another undergoing acceleration to maintain a specified trajectory. Now it is not fair to compare two clocks that are spatially separated, but if you idealize so that the satellite clock leaves the earth and returns later, which can be done with minimal effect, then the satellite clock which follows a non-geodesic path, will record less time than the earth-bound clock which does have a geodesic world line in spacetime. This is essentially the "twin paradox" re-cast.
  9. I am sure that you do. Therein lies a great deal of the problem. Classical physics, including classical thermodynamics has proved to be an astonishingly sccurate predictor of everyday macroscopic natural phenomena. It is the basis for almost all of engineering (a notable exception is electronic devices). It is certainly the basis for the design of engines, compressors and heating and refrigeration equipment. You cannot simply toss aside such a large body of self-consistent theory because it does meet your personal preconceptions. Worse, you cannot toss aside selected parts and keep more personally appealing parts without destroying the self consistency of the overall structure. To go to the title of this thread, it is quite obvious that heat is not what you think it is. Apparently neither are work and energy. Now go read a physics book. The Feynman Lectures on Physics by Feynman, Leighton and Sands is one of the best.
  10. It is both necessary and sufficient. Sufficiency follows from the law of cosines.
  11. There is no simple explanation. Gravitational energy is not explicitly included in general relativity. Among other things this is what makes "conservation of energy" a bit of a problem in GR. http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html
  12. Where is the world did this come from ? There is all sorts of evidence for the constancy of the speed of light in a vacuum. Not the least of it is the fact that it is a fundamental axiom which underlies the Special Theory of Relativity. There is a mountain of evidence supporting SR, including direct measurements of c. Moreover, the constancy of the speed of light in a vacuum falls out of Maxwell's classical theory of electrodynamics. No number of irrelevant buzz words and allusions to rank speculation changes any of this.
  13. Science attempts to determine and explain how nature works. The local speed of light has been found to be constant in a myriad of experiments, and that fact is reflected in the general and special theories of relativity. It is also consistent with Maxwell's classical theory of electrodynamics. Why nature behaves as it is found to behave is a question for philosophers and theologians. As with all questions put to theologians and philosophers, you will not find a definitive answer.
  14. What in the world is that supposed to mean ? All forms of energy, except gravitational energy enter into the stress-energy tensor of general relativity, which determines spacetime curvature, which is gravity. Gravity also plays a role through the nonlinearities in the field equations, so in the words of Wheeler, "gravity gravitates".
  15. The largest known prime is a Mersenne prime. But it is unknown whether the number of Mersenne primes is infinite or finite. It is easy to prove that there are infinitely many prime numbers. So it is not fair to say that "all the really big primes are Mersenne primes.
  16. The law is that the gravitational force is [math]F=G \dfrac {m_1m_2}{r^2}[/math] It is not that "all bodies fall in a vacuum at the same acceleration 9,8m/s^2". Other forces also apply to an accelerating charged body. http://en.wikipedia....93Lorentz_force
  17. [math]x+a = \ (^3\sqrt {x+a})^3[/math]
  18. My understanding is that no string theory has yet been clearly defined and that some theorists, Brian Green for instance, have suggested that Maldecena's AdS/CFT correspondence (itself an unproved conjecture since 1997) might eventually be used as a definition of string theory. M-theory arose from a presentation and paper of Witten (in 1995) that offered a plasusibility argument for the unification of the then-competing string theories inder the umbrella of a single theory, M-theory. However the "dictionary" among those string theories has yet to be produced and what exists are conjectures regarding various symmetries that might produce the desired dictionary. So the most pressing problem in M-theory remains "What is M-theory ?" Popularizations of string theory, IMO, present a badly distorted view of the maturity of the subject and wildly overstate the justifibility of conclusions regarding physics that can be drawn. So far as I know there have been zero new testable predictions from string theories, but a lot of hype about its implications for cosmology and particle physics. The exception to the overhyping that characterizes many authors is Witten, who generally presents a very objective view of the subject. Witten ought to know. Without spectrographic data, I would not believe Kaku if he said the sky were blue .
  19. Modern Systems Theory, which has little to do with your New Age mumbo jumbo, arguably began with the work of Rudolph Kalman and the introduction of the state space approach to control systems during his early work in the 1958-1962 framework. That philosophy was itself based somewhat loosely on Lagrangian mechanics. Kalman at that time had an understanding of linear algebra that was atypical of the engineering community, and he exploited that understanding and an understanding of functional analysis to formulate and solve the linear quadratic Gaussian problem, which remains the benchmark for both optimal control and stochastic control. Along the way he introduced the fundamental notions of controllability and observability for linear systems and introduced the Lyapunov approach to stability of non-linear differential equations to the engineering community. Kalman's approach fostered the development of a broader discipline, known as systems theory, that was applied t a broad spectrum of issues. The IEEE Journal of Systems. Man and Cybernetics was founded and continues to this day, though with little fanfare and no notable successes. Some classic texts arose from this study, notably Linear System Theory by Zadeh and Desoer and Topics in Mathematical System Theory by Kalman, Falb and Arbib. In the 1970's Kalman felt that he had exploited what he called "continuous mathematics" about as much as he could, and turned to algebra, particularly the theory of Noetherian rings, to attempt to develop an algebraic theory of realization for systems. Little came of this. The impact of the systems perspective was profound in control theory, computer science and automata theory, communication and information theory, economics, and mathematical biology among other disciplines. But it is most certainly NOT a "new science' or any sort of a surrogate for basic physics. The term "systems" has morphed and is used by different groups to describe wildly different things, from simple logistics to abstract applications of functional analysis to abstract problems of interest to mathematicians. It has been used, misused and abused to the point where one must now look closely at the specifics to be able to separate the wheat from the chaff. You appear to have isolated and retained the chaff.
  20. YouTube posts are a poor source. That one is not an exception. Start here Then read real science books. Principles of Physical Cosmology by Peebles might be a good place to start.
  21. n points on a graph give you n equations for the n coefficients of a polynomial of degree n-1.
  22. In general a polynomial is not determined solely by its real zeros, even up to a multiple. So while [math] (x+4)x(x-6) [/math] is a factor of the specified polynomial, it is not the whole thing. In general given n points there will be a polynomial of degree n-1 passing through those points. There will also be polynomials of higher degree, so the points that you have listed do not define a unique function.
  23. A good start would be for someone to actully define what M-theory is, or even to rigorously define a string theory.
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