Einstein Definition and 811 Threads

How could it be tested that there exists true randomness in the universe? One could simply argue that the is information that we do not posses that causes the outcome of a measurement to occur, right?

In this http://web.stanford.edu/~oas/SI/SRGR/notes/SRGRLect6_2007.pdf, it is stated: Likewise, objects in spacetime all move at constant speed c in spacetime but if you change its direction, say by moving at speed v in the x direction, then spatial speed will change and so will the speed along...

A falling apple made Newton to think about gravity. What made Einstien to think and develop his theory of relativity ? What devices/apparatus/equipment did he use for his theory of relativity ?

I vaguely remember reading a quote by Einstein related to a physics matter where he said something like "That would be double counting" (i.e. Don't do it). Does this sound familiar to anyone? What was he talking about? Note that this was not a wimsical quote. He was talking about a serious...

The Einstein gravitational constant (Κ) is usually written as; Κ = 8πG/c4 Can this constant be represented as wave-particle ratios of force? One ratio is a thermal ratio, it includes Plank temperature and Hawking temperature. The other ratio is a particle ratio including Plank mass. Can...

Homework Statement My question is regarding a single step in a solution to a given problem. The step begins at: ##\large \frac{\partial \alpha _j}{\partial x ^i} \frac{\partial x^i}{y^p} \frac{\partial x^j}{\partial y^q} - \frac{\partial \alpha _j}{\partial x ^i} \frac{\partial x^i}{\partial...

Is there a simple geometric interpretation of the Einstein tensor ? I know about its algebraic definitions ( i.e. via contraction of Riemann's double dual, as a combination of Ricci tensor and Ricci scalar etc etc ), but I am finding it hard to actually understand it geometrically...

The Equivalence Principle says depicting gravity as a field associated with matter is equivalent to picturing it as twisting of space. Is there a space-twisting equivalent of a collapsed star as a shell of condensed matter with interior of intense gravitational field energy (found in the field...

In 1916 Einstein has published the first paper of gravitational wave bu linearize approximation but It contain an error of his calculation then In 1918 he published a new paper of gravitational wave that has a correction of the his last error and conclude that there are the Gravitational wave...

If we take a look at the experiment were two observers A (inside a train) and B on the platform observering the train as it pass by. Person A will stand in the exact middle of the train and send out a light wave. Person A will observe the light to hit the wall at the same time, while person two...

If gravity is the warping of space, how does it work on Earth for us? Imagine a trampoline (the most common example for describing gravity) when a bowling ball is kept on a trampoline the weight of the ball forces the trampoline to stretch, but on our planet the gravity works downward on the...

I recently thought about time. And I know from my days in school, that a second is determined by the radiation of Caesium-133. But I also know, that the duration of a second depends of where you measure it...like on a planet with a huge mass traveling very fast OR on a planet with low mass...

so i am somewhat new to the theory of general relativity but in none of the papers i have read does anyone seem to explain what causes matter to attract... for example, the moon and the Earth are attracted to each other because each of them warps spacetime around themselves. these warped pockets...

The news out of LIGO is being heralded as one of the most important experimental verifications of physics in decades, as it provides experimental support to the General Theory. The news makes it seem as though it were like the Higgs Boson was; theoretically concrete, but up in the air until...

Could someone please describe the recent LIGO project, gravitational waves and their detection in simple terms. PLEASE.

For some time now I’ve been intrigued by the famous argument between Bohr and Einstein, and which was apparently settled when Bell’s inequality was tested in various experiments carried out by Alain Aspect. After going around and around the whole issue for a while, I don’t think I’m convinced...

Was the wormhole discovered by Einstein and Rosen formed by a black hole and a white hole?

Hey guys, i am not a science guy by any means so any answer written for the layman would be much appreciated. i may not be understanding this right but here it goes: In einstein's relativity of simultaneity we talk about how events A,B, and C are simultaneous for one observer (lets call him...

Can these tensor be seen as operators on two elements. So given two elements of something they produce something, for instance a scalar ?

∇2g00 = 8πGρ According to drphysics, as this is not a tensor equation, we need to change it such that it fits general relativity. Gμv = 8πGTμv T00 is the energy density. The conversion of the density(ρ) to T00 is it done through E=mc2? ρ=E/c2 And since is T00, it will be over c4 instead of...

This Millennial Might Be the New Einstein http://news.yahoo.com/millennial-might-einstein-080000030.html?nf=1

This is maybe more a maths question. In part 3 of his 1905 SR paper, how does Einstein solves the following PDE : to get : ?

A short film celebrating the centennial of Einstein's theory of General Relativity. EOIN DUFFY Animation (http://eoinduffy.me/) DAVID TENNANT Narrator WESLEY...

In section 4.4 of gravitational radiation chapter in Wald's general relativity, eq.4.4.49 shows the far-field generated by a variable mass quadrupole: \gamma_{\mu \nu}(t,r)=\frac{2}{3R} \frac{d^2 q_{\mu \nu}}{dt^2} \bigg|_{t'=t-R/c} I have the following field from a rotating binary...

Hello In Newtonian theory Poisson's equation holds: ## \nabla ^{2} U = 4 \pi G \rho ##. So: given a density ##\rho ##, it is possible to find a potential U. On the other hand, I can choose a random function U and give it a gravitational significance if it gives, by Poisson's eq., a density...

The answer is given as (a). I want to know the reason. It is a boson. Why can't it form a Bose-Einstein condensate?

Hello, can somebody please help me understanding the following. Action of general relativity consists of two terms: action of gravitation, dependent on metric tensor and its derivatives; action of matter, say one freely moving point mass particle, dependent on particle coordinates and metric...

Hi, I am reading the Einstein original paper on Special Relativity, in this link (English translation), I am having difficulties on this sentence: "We have now to show, that every ray of light moves in the moving system with a velocity c (when measured in the moving system), in case, as we have...

Randall Munroe, creator of the webcomic XKCD, wrote a piece for the New Yorker, in which he explains special and general relativity using only the thousand most common words in the English language. Here's an excerpt. Read the full piece at...

I just watched the first part of Brian Greene's television program on PBS The Elegant Universe. In The Elegant Universe, the narrator shows a model of the solar system, and the narrator says that according to Newtonian theory, if the sun disappeared, the Earth's trajectory around the sun would...

I can not understand what exactly this principle says.while reading a book about it ,it was written that einstein abolished gravity by saying the lift is free falling can some explain clearly what does that mean?

If you could magically go back in time, and spend two hours with Einstein shortly before he died in 1955, could you explain to him current modern superstring theory? If so, what would he think of it?

Hi, this is my first message on thi forum :D I apologize in advance for my english. I'm doing my thesis work on the theory of relativity of Einstein-Cartan. I'm following the article of Hehl of 1976; it's title is "General relativity with spin and torsion: Foundations and prospects". I can't...

Hey guys, I'm new to this forum. I make YouTube videos where I talk about science in video games / pop culture. Being a mechanical engineer I can usually get by pretty good, but this one has me totally lost. Could the Halo energy sword actually exist and if so, how could we (or the universe)...

If light travels in a straight line , why can't we use it as absolute frame of reference? This thought experiment is done in the absence of external forces and gravity. One person standing inside a box ,sends a photon parallel to the bottom of the box from one end to another end , whether...

I'm wondering if a ship orbited a black hole for a year, how large would the black hole be for it to equal 10,000 years on earth?

It took einstein 4 years to complete his general theory of relativity but the fundamental idea behind this work is that he believed that space is curved , how he is sure about this idea from the beginning ?

Question outline: In the case of 5d Kaluza (Klein) GR with NO charge and NO gauge field we expect 5d to reduce to 4d GR exactly. So this should be a very simple useful sanity check.s the side and corner terms of Einstein, Ricci and Energy tensors are zero, then R would be the same in 4d or 5d...

Hello I'm new here on this forum and on physics too. I have problem on Einstein famous equation I have a problem on the last component Tαβ I know that tensor name is Einstein stress-energy tensor and I know that Tαβ...

Per my layman's understanding, the apparent force of gravity, as explained by the general theory of relativity, is actually the result of rectilinear motion at uniform speed through warped spacetime. 1. If that's the case, what actually causes gravity for objects at rest with respect to the...

I was reading Einstein's seminal work: http://hermes.ffn.ub.es/luisnavarro/nuevo_maletin/Einstein_1905_relativity.pdfGo to this part: II. ELECTRODYNAMICAL PART § 6. Transformation of the Maxwell-Hertz Equations for Empty Space. On the Nature of the Electromotive Forces Occurring in a Magnetic...

Homework Statement Using the special relativity formulae p = mv / [1 - (v/c)2] E2 = p2c2 + m2c4 derive linear relations between: (i) momentum and mass; (ii) energy and mass; (iii) energy and momentum, which involve only c, c2, β = v/c, and γ (= 1/sqrt(1 - β2)) The attempt at a solution I am...

According to Einsteinian Relativity, is the Universe considerably younger if one was to view it from within a greater distortion of the gravitational field? Is the value we assign for flat or non-flat universal age dependant on our own point of reference for time?

We all know the experiment - here It says that for the observer on a train the lightning strike that we are traveling to happened first, but I have some questions. 1) We are moving towards right, so we must see the right lightning first. And we are moving away from left lightning so that...

According to Hawking [1] it is posited that light photons at the event horizon of a black hole must cease to move, and remain motionless for the entire lifetime of the black hole. It is also observed [http://dls.physics.ucdavis.edu/~scranton/LensedCMB/a2218.gif] (and calculated) that the path...

Here's a question that has bugged me for a while. The full Riemann curvature tensor R^\mu_{\nu \lambda \sigma} can be split into the Einstein tensor, G_{\mu \nu}, which vanishes in vacuum, and the Weyl tensor C^\mu_{\nu \lambda \sigma}, which does not. (I'm a little unclear on whether R^\mu_{\nu...

There's a somehow related set of issues I find myself pondering time and again: In 1995, Ted Jacobson derived Einstein's equations from thermodynamics across a horizon. Roughly, he showed that if the horizon's entropy is given by the Bekenstein-Hawking formula, then the second law of...

I would like to write the HIlbert-Einstein action using tetrad formalism. I have seen in a paper that the lagrangian is the contraction between a levi civita tensor, against two veilbeins and a two form curvature. The problem is that i can' t prove that this is the same as the scalar curvature...

Hello dear Physicists, I am very curious about understanding the math and the nature properties of the Einstein Field Equations.What I need to know is,what concrete mathematical operations I need to know and understand,and have experience with to understend this theory.I'm a quick learner and...

Homework Statement Demonstrate that Eq. (1.1) will convert to the Einstein relation Eq. (1.2) in the limit of t→∞ when we assume ξ=6πaμ. Conversely, show that Eq. (1.1) will yield <x2> ~ t2 in the limit of t→0. Confirm the consistency of the principle of equipartition of energy. Homework...