Einstein Definition and 809 Threads

Can someone explain the equation G_{\mu\nu}+\Lambda g_ {\mulnu}={8\ pi G\over c^4} T_{\mu\nu}\ by Albert Einstein?

I was wondering why Einstein picked C for this equation. C is just one spot on the energy spectrum, the high end of which we are probably not yet aware. A nuclear explosion, for example, produces energy in the full range, sound, microwave, radio, etc., (we assigned names for identifying...

Homework Statement Hi, I need to know the correct SI units for Einstein Coefficients (A and B) for stimulated emission (say laser). The equation I'm on about is Homework Equations \frac{A}{B} = \frac{8\pi h\nu^{3}}{c^{3}}The Attempt at a Solution after some scribbling I got to \frac{A}{B}...

I'm wondering if there are any good programs to calculate the various tensors that one needs to solve the Einstein field equations for a very general metric i.e. metric components are not specified explicitly, only their functional dependence on the coordinates e.g. ds^2=-n^2(\tau,y)d\tau^2 +...

If both Isaac Newton and Albert Einstein are still alive today, imagine the world we will be living in and the impact on all theories of physics! Can you imagine what the world will be like with them still around?

Did Einstein ever say how he came up with the fact that the speed of light is always constant .

Hi everyone I need the historical articles that bose and fermi integrals were defined for the first time. Can anyone help me?

Before I begin, I stress that this is NOT a homework question but rather a self-study question. In any case, I calculated the Einstein Tensor of a body with the metric diag[{2GM/r-1,0,0,0},{0,1+2GM/r,0,0},{0,0,1+2GM/r,0},{0,0,0,1+2GM/r}]. What does the Einstein Tensor represent? Does its...

The following is the Einstein’s train but instead of train consider two airships of equal in lengths. http://www.youtube.com/watch?v=wteiuxyqtoM&feature=related Both are moving with same speed but opposite in direction. After certain time they cross each other such that one is exactly...

Homework Statement This question is a slightly customised version of Q18(a) P212 of Schutz Prove that G_{\alpha \beta} + \Lambda g_{\alpha \beta} = 8 \pi T_{\alpha \beta} in the Newtonian limit reduces to \nabla^2 \phi = 4\pi \rho + \Lambda (I found this result in another text...

Gµv + Λgµv = (8πG/c4)Tµv I have several questions. what is the µv? when we use it today do we use the cosmological constant even though the universe isn't static or does it mean something different than einstein orignally thought? what are we measuring when we use this if theyre all constants?

i heard it was becuase it was to over the heads of the Committee is this true?

Subject: A Baffling Quote from Einstein, badly requiring explanation All sources I've consulted indicate that Einstein reconceived gravity in General Relativity by discarding the prevailing, intuitive, Newtonian view of it as a 'force' accelerating objects, and daringly envisioned it purely...

Homework Statement Show that the multiplicity of an Einstein solid with large N and q is \frac{\left(\frac{q+N}{q}\right)^q\left(\frac{q+N}{N}\right)^N}{\sqrt{2\pi q\left(q+N\right)/N}} Homework Equations N! \approx N^N e^{-N} \sqrt{2 \pi N} The Attempt at a Solution Well...

Although Albert Einstein had explained the new picture of gravity through his theory of general relativity, by explaining that gravity is the warping of spacetime, did he explain why mass actually warps this fabric of spacetime?

If I have a (1,1) tensor, eg a Lorentz transform, how do I write its inverse? For example: x'^\mu=\Lambda^\mu_\nu x^\nu Would I multiply on the left by: (\Lambda^{-1})^\nu_\mu? It seems to make sense, but I'm not 100% sure. I'd prefer to not use anything from matrix multiplication...

Just wondered if the following extract is historically correct ... Einstein's and now main stream's current gravity theory is based on the belief that if you were accelerating in a spacecraft you wouldn't be able to distinguish between this experience and that of gravity. It was then...

Homework Statement Use the equation ln(q+N) to derived an equation similar to the equation, omega(N,q)=e^(N*ln(q/N))*e^(N)=(eq/N)^N only when q >> N, for a multiplicity of an einstein solid in the "low temperature" limit , q<<N Homework Equations ln(q+N) ln...

Homework Statement For an einstein solid with four oscillators and two unites of energy, represent each possible microstate as a series of dots and vertical lines. Homework Equations no relevant equations The Attempt at a Solution I won't list all my microstates, just a couple of...

Homework Statement From the formula t = \frac{L}{v+c} + \frac{L}{v-c} I've made t = \frac{2L}{c}\left(\frac{1}{1 - \frac{v^2}{c^2}}\right). This is the problem: \left(\frac{1}{1 - \frac{v^2}{c^2}}\right) = \left(\frac{1 + \frac{v^2}{c^2}}{1 - \left(\frac{v^2}{c^2}\right)^2}\right) How...

Homework Statement Consider the interation of two einstein solids, A and B. A has NA particles and qA units of energy and B has NB and qB units of energy. find the most probable values of qA and qB when equilibrium is reached. Homework Equations The Attempt at a Solution I set up...

Homework Statement (a) The formula for the multiplicity of an Einstein solid in the “high-temperature” limit, q >> N, was derived in one of the lectures. Use the same methods to show that the multiplicity of an Einstein solid in the “low-temperature” limit, q << N, is Ω(N,q)=(eN/q)^q...

This is more of a historical question than an actual physics question sorry... but it is physics related so here it goes I know when they first met Einstein and Bohr became good friends but does anyone know if they stayed that after all their famous debates about the paradoxes of quantum...

The title of this thread comes from https://www.physicsforums.com/showpost.php?p=2038753&postcount=23" in the Cosmology section of PF. It started a mini-thread that has nothing to do with cosmology, but it's quite interesting, so I thought I'd kick off a discussion here. The general topic...

How did Einstein come to pushish his general theory of relativity? Was it in a series of papers over a few years, or in one definite article? In either case, are these (or this) papers available on the internet in engligh? Thanks.

If gravity is a force, then the moment the object producing gravity is taken away, it should result in gravity taken away instantaneously. However, why does Einstein say that Newton's classical mechanics are incorrect and that in fact he decided to propose spacetime and not follow what Newton...

http://arxiv.org/abs/0901.0640 Horizons and the cosmological constant Krzysztof A. Meissner 6 pages (Submitted on 6 Jan 2009) "A new solution of the Einstein equations for the point mass immersed in the de Sitter Universe is presented. The properties of the metric are very different from both...

It's becoming a little more well-known in recent years that Einstein was in fact a strong advocate for a "new ether" from 1916 until his death. He denied the 19th Century version of the ether in his 1905 paper on SR, and spent about 11 years defending his banishment of the ether from physics...

Could anyone explain: http://en.wikipedia.org/wiki/Einstein-Cartan_theory I don't understand why if #3 (Experimental effects are too small to be observed) there is a 'proof' #2? What is a 'flaw' if there are no observed effects?

Photo of Einstein, Hubble, and LeMaitre together?? Hey, I was wondering if anyone knew where i could find a picture of Einstein, Hubble, and LeMaitre together. I think they were all together in California in the 1930s and if anyone knows anything about this, i'd really appreciate the insight...

Consider the relative position of the inertial reference frames I and I’ as detected from I when the standard synchronized clocks of that frame read t. The reference frames I and I’ are in the arrangement which leads to the Lorentz transformations of the space-time coordinates of the same event...

Homework Statement the stiffness of the interatomic "spring" (chemical bond) between atoms in a block of lead is 5 N/m. Since in our model each atom is connected to two springs, each half the length of the interatomic bond, the effective "interatomic spring stiffness" for an oscillator is 4*5...

I stumbled across the following list of Einstein's papers... Somebody asked a related question on this forum recently...and this would help. http://en.wikipedia.org/wiki/List_of_scientific_publications_by_Albert_Einstein Is there a better place to post this?? Can it be posted in the...

i heard this story a while back: einstein was given a toy by one of his long time friends. it was a little ball with a string attached. the objective of the toy was to get the ball on the string to sit on the rod... here's a picture that looks like the toy i remembered in the photo...

Einstein Online is an amazingly informative website that the AEI (Albert Einstein Institute) started in 2006 and is still adding to. They have a section on cosmology that is the best introduction I know of not needing a lot of math. Indeed it is nearly math-free but still manages to be...

Dear all, I'm coding the calculation of the free energy of an SiO2 crystal structure Using a 2-body Buckingham potential. I'm attempting to use the method of Frenkel and Ladd which consist in transform your solid reversibly into an Einstein crystal. I've read the excellent book...

Why do we ever get Einstein crosses? I realize it is because the alignment is not right, but why do we get a cross because of this instead of just a skewed ring? Thanks, Jamie

Was Einstein too optimistic? I’m beginning to suspect that this philosophical view is nonsense. There seem to be many aspects of the physical world that are really difficult to understand and fully accept. But then lots of people grasp stuff better than I do. I’ve been trying to devise...

When it is about the "Lorentz transformations" I have in mind: There is indeed a state of real rest, defined by the ether. Hearing about "Einstein transformations" I would think: The notions of "really resting" and "really moving" are meaningless. Only relative motion of two or more uniformly...

So back around 2006 I was reading a bunch about how people were worried that the "Beyond Einstein" program was losing its funding. This was a set of five or so astronomy probes investigating edge astrophysics, and they were talking about funding maybe one or two of them (one of the probes was...

A couple questions. Assume that you can travel arbitraily close to the speed of light and that you have figured out how to communicate via Quantum entanglement (Like Ender's Game). I speed away from Earth at almost the speed of light. At the point when I stop accelerating, is it not valid...

Imagine we have an ideal Schwarzschild black hole. A small satellite of insignificant mass (so that the Shwarzchild geometry remains ideal) is orbiting at coordinate radius R just outside the photon orbit in a perfect circular orbit. For the purpose of this experiment ignore the orbital decay...

Solving the Einstein eq. i found the following differential eq. that would descrive the metric inside a body: x2d2y(x)/dx2+2xD1(y)dy(x)/dx+D2(y)=0 where D1(y) and D2(y) are known function of y and 0<=x<=1. I try to solve numerically but looks like there is a cusp; any suggestion how to...

Could someone please help me understand the Einstein hole argument (as outlined by Norton, see below). In particular the step that says that the second solution within the hole is a valid solution to the generally covariant field equation. I think my understanding of general covariance is at...

Hi, I have a problem with deriving Einstein equations : \epsilon_{IJKL}(e^{I} \wedge R^{JK} + \lambda e^{I} \wedge e^{J} \wedge e^{K}) = 0 de^{I} + \omega^{I}_{J} \wedge e^{J} = 0 From the action : S[e , \omega] = \frac{1}{16 \pi G} \int \epsilon_{IJKL} (e^{I} \wedge e^{J} \wedge...

What physical meaning can be ascribed to the non-divergence of the Einstein tensor? I find it counterintuitive since I associate divergence with field sources (like the electrical field of a proton) and obviously a gravitational field has a source. Is there a parallel with Newton's formulation...

1. Absolute simultaneity with standard synchronized clocks In an one space dimensions approach we propose the following scenario. At the origin O of the inertial reference frame I we find a clock C0(0) and a source of light S(0). An observer R’ moves with constant speed V in the positive...

I had just by chance mentioned something about Albert Einstein today to my colleague when a heated debate began at the office. We were talking as usual when he threw out that although Einstein was an accomplished physicist, Isaac Newton was the greater of the two because of his work in...

Hi, Why is -BEi used instead of +BEi as the lagrange multiplier for indistinguishable particles? How is it justified? I've been reading a book about statistical mechanics and it introduces lagrange multipliers first for distinguishable particles- it has ln(ni) + a + BEi = 0. (where a is...

I'm curious about how people here view Einstein's prescription for determining simultaneity in an inertial frame, and how the extension of that approach to other inertial frames spawns the Lorentz transformation. It seems to me the competing pictures here are that this is an arbitrary way (in...