# Tag Info

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See the question Laws and theories and the answers to it. The terms law and theory are somewhat vaguely defined so your question doesn't make sense. Relativity, both special and general, is well enough tested that physicists regard it as an excellent working description of the universe. However it can only be an effective theory since it does not take into ...

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Your question has several flaws. First, you say the electron is at rest at the origin. As John Rennie noted, this implies that the position and momentum are both sharp, which contradicts the uncertainty principle. There is no such thing as an electron at rest at a particular point. An electron is described by a wave function spread over an extended region ...

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If you say: According to me the electron is at rest. that means you have measured the electron momentum to be zero, in which case the electron position is completely uncertain. So you can't be sitting on the electron. If you say: Let us say I sit on an electron. that means you have measured its position precisely so you have no idea what its ...

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Since I am not aware of any aspect of gravitational theory which corresponds to magnetism, I do not see how gravitational theory can account for the effects of motion. Gravitomagnetism is in fact a known and measured phenomenon. It emerges from Einstein's general relativity, rather than Newtonian gravity (which, as has been noted in other answers, is ...

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Yes. General Relativity is perfectly capable of showing how a large oblate spheroid of gas moving in a particular direction contracts to form an oblate spheroid shaped star moving in that same direction that shines and emits light. And it is perfectly capable of making models that predict all the observations that any observer would make. Frankly, its a ...

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Is there some aspect of the theory of gravitation, either Newtonian Newtonian gravitation has instantaneous transmission of the gravitational field or Einsteinian, by which an object's gravitational field is modified by its motion, so as to produce this effect? In general relativity Lorenz transformations are inherent at the flat limit, see ...

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Whenever you have mass you have energy too, lots of energy for a tiny bit of mass. And it is energy not mass, that is related to spacetime curvature. Your idea that mass curves spacetime and energy does not, is a lie, completely 100% baseless and simply untrue. It's just that the energy associated with mass is the largest energy you are used to seeing ...

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Yes, all 4-vectors transform as you state under a Lorentz transform. For the case of $\vec E$ and $\vec B$, they are indeed not 4-vectors. There are two ways of transforming the $\vec E$ and $\vec B$ fields to different coordinate frames. You can define the $A$ 4-vector in terms of the potential functions $\phi$ and $\vec A$, letting A = ...

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According to Einstein's theory of general relativity, both matter and energy curve spacetime. The theory already makes an allowance for matter-energy equivalence. The Einstein field equations are: $$G_{\mu\nu} + \Lambda g_{\mu\nu} = k T_{\mu\nu}$$ The left hand side has the Einstein tensor G which encapsulates the curvature of spacetime, and the right side ...

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Any finite physical system can be simulated by a universal computer. This includes quantum systems, which could be simulated by a universal quantum computer if we knew how to build one. Quantum mechanics is deterministic in the sense that the state of the whole of physical reality at one time can be worked out from the state at an earlier time given the ...

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Could the universe be accurately simulated with an infinitely powerful computer? First Could and infinitely powerful are not compatible. A system able to simulate / predict accurately anything is quite impossible : one would need a clone universe able to compute faster than the universe runs. Initial values, indistinguishability and uncertainty ...

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The uncertainty principle is often confused with the observer effect. The former says that the certainty in position times the certainty in the momentum is greater than some constant. We think of momentum and position as two different things, but the underlying physical phenomenon may not be. Of course, none of this speaks to whether or not quantum ...

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Your question actually contains many questions, which are all related but not so strictly so that it is possible to give a full answer to it. Is every event in the universe related to each other? There are various ways to answer this question. Straight forwardly, we have observed that there is a finite speed at which information can propagate in our ...

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By event I assume you mean interaction. There is certainly a randomness factor if our current theory of quantum mechanics is correct. The most obvious example is radio-active decay, but most any quantum mechanical interaction will include elements of randomness. As for the question of relatedness of events, the answer depends on what you mean by ...

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The answer to the title question (Is every event in the universe related to each other?) is clearly a no. Some events can't be related to others due to the fact that light has a finite and unsurpassable speed.

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As the person B takes off in a rocket, both of them would see the other clock move at a slower rate, assuming the rocket to be moving at a constant speed, both are in an inertial frames of reference, but when B wants to return to A, B should make a turn somewhere, so a turn, is an acceleration, and accelerating frame of reference is non-inertial, and this ...

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@CuriousOne posted this answer in the comments: The premise of relativity is that the speed of light is the same for all observers. This has consequences, but it doesn't change time. All clocks still behave exactly the same for all observers traveling with their own clocks. It is only between observers that clocks are running at different rate. This ...

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If I understand what the book pretends to show, the theory identified by the existence of $X^{\mu}(\tau)$ in an Lorentz-Poincaré symmetric spacetime can construct physical scalars only by some functionality of $\dot{X}^{\mu}\dot{X}_{\mu}$. The $\dot{}=d/d\tau$ came from the translations in space-time and the product $A_{\mu}B^{\mu}=g_{\mu\nu}A^{\mu}B^{\nu}$, ...

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Relativistic mass is indeed the time component of the 4-momentum, and that is exactly why is it NOT invariant.

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Per Danu's comment, if $m_0/\sqrt{1-v^2}$ were Lorentz invariant, it would follow (because $m_0$ is Lorentz invariant) that $v$ is Lorentz invariant. So neither relativistic mass nor anything proportional to it can be Lorentz invariant. Of course the notion, elsewhere in the comments, that it's somehow not possible to talk meaningfully about the ...

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