Is Einstein's General Relativity realistically a valid Theory ?
103296
Relativly speaking, it appears to be if you know how to do the math, but until somebody actually manages to accelerate themself to the speed of light and lives to tell what it was like, nobody will ever know for sure.
384756
Yup, relativity and qunatum mechanics work together nicely.  You'll need to account for the switch to using spacetime quantities instead of space and time quantities, and the fundemental equations get kind of hairy, but they still work out fine.
933949
Theory of relativity.
1073869
It hasn't been completely accepted, but it is widely believed to be the correct direction to go.  They are still trimming the fat, and many of the theories will never be tested as we can not experience some things that occur in the extra dimensions that we can not see, according to string theory.  (Theory is not accepted as fact, its a theory)
99456
Einstein alluded about forces saying that they are fictitious.This make sense because forces do not exist unless there is an interaction between two entities.\nThe magnetudes of interaction depends on the densities of the masses and their volume.The greater the densities the greater the interaction.Thus we can categorize them.\nHowever ;the mechanisms involved is the same in all interactions!Einstein Related this mechanism to a curvature.\nHe had discovered when a force comes into being it comes  from a common  mechanism(.A force is a force ). Force only come into being only as pairs.A force cannot exist by itself no more than a magnet having a single pole.\nUnfortunately ,He had the basis for a Unified Theory and did not realize it.\nAs far what has been measured in the interaction of micromasses or micromasses,I  dont believe there is anything exact.Only approximtions.\nThe phenomena of gravity apply to both micromasses as well as Macromasses.This is the only thing that is Realistic.\nIn other words Electrical phenomena as well Gavity are all one and the same Phenomena.\nYou may not agree with it but its a more realistic answer than resorting to the aphabetic soup of forces that the Physists have concocted as saying that they are different Phenomenae.\nIf you dont understand about their description of weak,strong nuclear forces, dont feel bad. I doubt that they fully understand it themselves!
44696
While Wikipedia rightfully gives credit for the idea to Georges Lemaître, his idea was built on the work of other great scientists of his time. Einstein's general theory of relativity was the foundation for work done by  Alexander Friedmann prior to Lemaître's work. Freidmann proposed with mathematical equations that the universe was expanding. After Lemaître proposed his ideas Hubble provided the proof that was needed. Many cosmologists actually give the credit for the Big Bang theory to Hubble. \nhttp://www.umich.edu/~gs265/bigbang.htm\nHowever, many other scientists deserve significant credit for later providing more proof and evidence to support and modify the original theory. Although it is widely accepted today, there are alternative scientific theories that have not been completely dismissed. One of these was proposed in 1993 based on observations of the accelerating universe. This quasi-steady-state theory is not well accepted, but is an example of how the Big Bang Theory is being constantly tested and re-examined by science as new evidence is found.
635497
enough to admire it\n\nQM is here to stay like it or not (Einstein did not)\n\nIt is not just a theory but the most provable experimentally modern fundamental theory of the subatomic world.\n\nUnlike the Relativity and other classics theories, it is not a deterministic but "statistical" one. We can know this and that with certain degrees of probability -- that's what QM tells us. It works and that's whats counts at the end\n\n"There is nothing more practical than a GOOD theory."
635775
No responsible science instructor would suggest that Darwin's theory is a fact. It may be supported by a massive preponderance of evidence, but is nonetheless theory. That said, gravity is a theory as well, but no one floats away.\n\nBiology students need only to understand Darwin's theory and to be able to work with it, not to believe that is a fact or even to believe that it is the best theory.
93504
The predictions of quantum mechanics are incredible, it is true. Especially in the more extreme reaches, like quantum electrodynamics, and quantum gravity, and quantum chromodynamics, and quantum teleportation, etc. Absolutely amazing. \n\nHowever, as much as these predictions do not agree with our intuition, they have been verified over and over and over for decades and decades. So although it seems like nonsense, it appears to explain what we observe, and to make predictions which we can verify. \n\nSo is it believable? I guess it depends on what you mean by believable. It certainly does not agree with our day to day experiences and intuition. Is it repeatable, and does it make predictions that we find useful? Yes.
176321
According to Wikipedia ( http://en.wikipedia.org/wiki/Theory_of_relativity ):\n"Albert Einstein's theory of relativity, or simply relativity, refers specifically to two theories: special relativity and general relativity. As a field of study, relativity also includes metric theories of gravitation in which special relativity applies locally.\nThe term "relativity" was coined by Max Planck in 1908 to emphasize how special relativity (which at that time was the only relativity theory)\n uses the principle of relativity.\nSpecial relativity\n\nMain article: Special relativity\nEinstein's 1905 paper "On the Electrodynamics of Moving Bodies" introduced the special theory of relativity. Special relativity considers that observers in inertial reference frames, which are in uniform motion relative to one another, cannot perform any experiment to determine which one of them is "stationary". This is known as the principle of relativity. While this principle was not new to Einstein's work, he found that including electromagnetism in this principle required a new formalism with many surprising consequences. In particular, it required the speed of light in a vacuum to be the same for all these observers, regardless of their motion or the motion of the source of the light.\nOne of the strengths of special relativity is that it can be derived from only two premises (although Einstein did not derive it this way):\nThe speed of light in a vacuum is constant (specifically, 299,792,458 meters per second).\nThe laws of physics are the same in any inertial frame of reference. This means that the laws of physics observed by a hypothetical observer traveling with a relativistic particle must be the same as those observed by an observer who is stationary in the laboratory.\nThe famous equation E=mc² (the energy contained in the rest mass of an object is equal to the product of its mass and the square of the speed of light) is derived from this theory.\n[edit]\nGeneral relativity\n\nMain article: General relativity\nGeneral relativity was developed by Einstein in the years 1911 - 1915. General relativity is a geometrical theory which postulates that the presence of mass and energy "curves" spacetime, and this curvature affects the path of free particles (and even the path of light). It uses the mathematics of differential geometry and tensors in order to describe gravitation without the use of the force of gravity. This theory considers all observers to be equivalent, not only those moving with uniform speed."
110305
Oh for Pete's sake people, please don't answer if you don't know what you are talking about.\n\n\nNewton certainly did have a theory of relativity, as you would have discovered if you had bothered with even the most basic web search.\n\nNewtonian relativity in simple terms, hmmm.\n\nIn simple terms Newtonian relativity simply says that all motion is relative to the observer, and not absolute. As a result we can and must choose which object is moving and which is at rest, it isn't chosen for us.\n\nFor example, if I throw a ball at your head at 10km/hr it will have EXACTLY the same effect as if I tied the ball to a string and you ran it to it at 10 km/hr. It will hurt you just as much, and the ball will bounce just as far off your head. \n\nWe normally assume that when I throw the ball it is moving, and when you run into a ball it is stationary. Netwonian relativity simply says there is no reason to assume that, and no way to prove it. For all we can prove mathematically you and I might be moving when I throw the ball, and the ball might stand still.\n\nSo why do we all KNOW the thrown ball moved? Because we refer to things that happen outside of our little world of ball, you and me. Only by referring to something else not involved, like the ground, can we say who moves and who stands still.  \n\nAnd that is essentially where we get the term Relativitivity from. All movement has to be described relative to a point outside of the actions we are describing. It can't be described bythe actual actions. Only by saying that the ground stands still and the ball moves relative to the ground cn we say that the ball moved. And only by saying that the ground stands still and you and I don't move relative to the ground can we say that you and I are stationary.\n\nWhere it gets interesting in practial terms is when our reference point is also moving. What happens if we are in a moving train doing 100km/hr and I throw a ball at your head? For you and me exactly the same thing as if we were standing on the ground, because we are making all our claculations relative to the floor of the train. The floor of the trainis our reference point. Since you and I don't move relative to the floor, and the ball does move relative to the floor there is no  difefrence t standing in the ground. \n\nBut if you were standing on the ground and I was in the train and threw the ball at you the efect would be very different for you. The ball would now hit you at the speed of the train + the 10km/hr I threw it at you. It would hit you doing 110km/hr and possibly kill you. Because our only common reference point is the ground that you stand on we have t do all our claculations form that point. W eignore the floor of the trian I am standing on an measure the speed of the ball relative to the ground only.\n\nAnd that's Newtonian relativity in a nutshell. There are all sorts of mathemetical descriptions and qualifiers, but you said you wanted it in simple terms.
724425
General relativity is not the final answer, since Einstein was never able to come up with the "Theory of Everything," i.e., the Grand Unified Theory.
784346
well, it's simply that if you measure the speeds of galaxies, and their acceleration, and put all the data together, it shows that, at some point back in time, all the visible stuff in the universe was at the same "point" (it cannot exactly be a point, because that would be of infinite density, and Einstein's equations break down in such conditions).\n\napparently there are some people who seem to believe that God and the Big Bang are incompatible - but this is wrong, and actually quite a few scientists believe in God and simply put Him at the source of the Big Bang.
79989
Still more theory than fact.\nIt is responsible for the force of gravity.
292660
http://en.wikipedia.org/wiki/Theory_of_relativity
876226
Visit this link for a good explanation:\n\nhttp://en.wikipedia.org/wiki/Theory_of_relativity
42478
I think you have the wrong idea.  The reconciliation between the theory of relativity and Newtonian physics is intrinsic to relativity itself.  When you consider the theory of relativity in the limit of small magnitude velocities, you recover classical mechanics.\n\nI think you mean to ask whether there has been a theory combining the standard model of particle physics with the general theory of relativity in a manner that predicts both, and the answer is no.