Equivalence principle Definition and 157 Threads

Hi. There were theoretical (find transformations under which Maxwell's equations remain invariant) and experimental (speed of light is constant, Michelson-Morley) indications that made the development of SR inevitable. But what about GR? Was there a "need" for this theory or was Einstein just...

It is known that equivalence principle is good for understaning of general relativity (GR). This means comparison of the elevator and falling in homogenic gravitational field. But, I here somewhere something like "in the higher lever of GR, let us forget on principle of equivalence". How it is...

The Galilean equivalence principle (or weak equivalence principle) is the statement of the universality of free-fall under gravity. For example, according to Wikipedia, it can be stated as follows My question regards the limitation of the principle to point masses. Does universality of...

Frames under identical acceleration, regardless of whether due to gravity or accelerated motion, are locally identical but time runs slower in a gravity well. For example, at the center of a large mass (like the one pictured, below) time runs more slowly than for an inertial observer far from...

Assume we drill a hole through the Earth - through the center towards the other side. Then we use a telescope, point it through the hole and observe stars on the other side of the earth. The telescope experiences a constant acceleration from Earth's gravitation. Accelerated movements have an...

This extract is taken from Sean Carroll's textbook. It talks about a theory that respects the Weak Equivalence Principle but violates the Einstein Equivalence Principle. we could imagine a theory of gravity in which freely falling particles begin to rotate as they moved through a gravitational...

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...

Hello Forum, What is the whole reasoning and importance of discovering that the inertial mass, which is introduced as the resistance to change the state of motion and the gravitational mass, which promotes motion (the larger it is the larger the attractive force). The equivalence principle...

As I understand it, a Cartesian coordinate map (a coordinate map for which the line element takes the simple form ##ds^{2}=(dx^{1})^{2}+ (dx^{2})^{2}+\cdots +(dx^{n})^{2}##, and for which the coordinate basis ##\lbrace\frac{\partial}{\partial x^{\mu}}\rbrace## is orthonormal) can only be...

Andrei G. Lebed, "Breakdown of the equivalence between gravitational mass and energy for a composite quantum body," http://arxiv.org/abs/1404.4044 [corrected a mistake in the following paragraph] He seems to argue that hydrogen atoms moving from one region of space to another, with a different...

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?

OK, I'm sure I'm just not thinking about this the right way, so please point out my simple mistake. Imagine a charged particle and 2 observers. Observer S is stationary relative to the charged particle, so sees no magnetic field from it. Observer A moves back and forth in front of the...

Here is what I understand of the equivalence principle. However, given that the concept is still a bit cloudy to me, please tell me if I am wrong: The equivalence principle is a phenomena where all inertial objects experience the same laws of physics. In other words, if you were going at...

Equivalence principle says that gravitational forces are equivalent physically to inertial forces. Can someone explain what is meant by that and how was it concluded?

The references below describe two interrelated relativistic issues that come up when you try to describe radiation from point charges: 1. We normally expect that an accelerating charge would radiate, but this would seem to violate the equivalence principle. 2. Classical E&M can't describe point...

1-What is the different between the Einstein equivalence principle and the Strong equivalence principle? 2-Is it possible to formulate the Einstein equivalence principle in this way? "For every point in space time, always exist a chart / reference frame in which the metric in that point is...

An observer outside the rocket sees a light beam through a rocket that's accelerating. How will an observer inside the rocket see the light beam? (The problem is showed in the picture below) My friends and I had this problem at school today, and we couldn't decide which is right. Here are our...

[FONT=Verdana]I'm currently reading https://www.amazon.com/dp/0199236224/?tag=pfamazon01-20. The book claims that, according to the equivalence principle, acceleration and gravity have the same effects. So if gravity slows down time, shouldn't acceleration also slow down time? The book seems to...

Mentor Note: This thread has been separated out of a previous one to keep discussion of this particular topic open, since the previous thread has been closed. Sorry, the opportunity to ask questions is just too hard to resist. I'm still searching for the right understanding of equivalence. Or...

Imagine an electric dipole with charges ##+q##, ##-q##, mass ##m## and size ##d##. Assume this dipole is oriented horizontally and is sitting at rest on top of some weighing scales on earth. As the charges are at rest the weight of the dipole is just ##-mg##. But by the principle of...

I'd like to see for myself the Equivalence Principle. Would there be a commercially available test kit like perhaps a small iron and cotton enclosed in vacuum tubes and they are to fall at same time and hit the bottom at same time with indicator lights to tell if they hit at same time or at bit...

I am new to relativity, so bare with me. I do not want to argue against it; however, one must admit it is a rather awesomely unwieldy theory. In my self education on the subject, I am bothered by the Equivalence Principle, mainly this: An elevator accelerating through space is no different from...

...through inertial mass, namely to explain away the sameness of inertial and gravitational mass? If you assume that only inertial mass is a "real" effect, then gravity would simply become a fictious force arising from inertial mass holding matter back from expanding alongside spacetime during...

Here are the 2 situations: Situation A: a person floating in space far away from any mass (i.e. the person is in zero-gravity environment) Situation B: a person undergoes a free-fall from the top of a roller coaster (assuming that there's no air resistance) My question is, would the person in...

Say we have an elevator moving through deep space at a constant velocity. We have a light emitter at the "top" of the elevator pointing towards a detector at the bottom of the elevator. We shine the light and notice that the frequency at which the light was emitted at the top is the same as...

Desloge (1989) published the article: ## '##Non-equivalence of a uniformly accelerating reference frame and a frame at rest in a uniform gravitational field## '##. His result, briefly resumed: a uniform gravitational field is not flat, is quite interesting. But the way he proves the result is...

Someone noted that the famous muon half-life experiment, supporting time dilation in SRT, seems to violate the equivalence principle of GRT. The very large radial acceleration in the experiment does not appear to cause any additional slowing. The acceleration does not seem to have an equivalent...

Hi pf, I have recently watched a YouTube physics video from SixtySymbols channel which is a channel of short physics videos presented by professors of physics from Nottingham University. The video (pasted below) argues that because of inertial mass and gravitational mass being equivalent this...

Homework Statement A photon near the surface of the Earth travels a horizontal distance of 3 km. How far (in meters) does the photon 'fall' in this time? (Hint: think equivalence principle). Homework Equations N/A The Attempt at a Solution My understanding of the equivalence...

Hi! How this paper relates to the equivalence principle? http://arxiv.org/pdf/gr-qc/0701084.pdf "in contrast to the situation with static gravitational forces, the effects of accelerative gee-forces on the internal observer are increased"

Hi I am reading Stephan Hawking's Universe in the Nutshell and there I didnt understand this sentence "This equivalence didn't work for a spherical Earth because people on opposite sides of the world would be getting farther away from each other.Einstein overcome this idea to make spacetime...

Hey, you know the way einstein said that its impossible to tell if you`re in a box that is accelerating or in a gravitational field? But, don`t accelerating charges radiate? so theoretically, by looking at these charges you could in fact tell the difference ? I dunno, maybe I`m missing...

Sorry for some probably very basic questions, but here goes. If gravity equals acceleration, how is the Earth's gravity defined by acceleration? If an accelerating body distorts spacetime, as described in Einstein's thought experiment about a light beam shined through an accelerating box...

Hey everyone, I started reading up on GR a couple of days ago, and I'm somewhat stuck on the concept of a free-falling IRF. I understand that an observer on a free-falling small spaceship would experience the laws of physics in a rather simple form, eliminating the need for a force of gravity...

Hi, So I came across this article on the internet, and it was about the Equivalence Principle. So I were interested and read it all, and in the article it said that the EP might be only approximately true. What interested me more about the article was it said that any theory of quantum...

I've been giving some thought to the new scientist article about the equivalence principle. What initially seems like a very simple issue is remarkably tantalising. (please note- I'm not a physicist so this may be quite stupid) This led me on a little to the question of gravity and direction...

Does a uniformly accelerated charged particle radiate em waves? The equivalence principle says that a particle in uniform acceleration is equivalent to a particle at rest in a gravitational field. A particle at rest in a gravitational field is clearly not going to radiate em waves therefore by...

I'm reading a book wherein the Earth's rotation is supposedly slowing down. The author claims that a ball thrown in the air would fall faster and harder... But if the rotation slows, wouldn't the equivalence principle say that the smaller acceleration could also be interpreted as a smaller force...

I have read the basis of the the equivalence principle, that inertial mass = gravitational mass, and that it leads to the conclusion that any acceleration = equivalent gravitational field intensity. (I believe 'gravitational field intensity' is the same as 'gravitational acceleration'.)...

I was just wondering if our use of a flat Minkowski background metric when looking at gravitational radiation in the weak-field limit is essentially done so that locally, for example with detectors on Earth, we can treat spacetime as being flat, but on a larger scale we use the equivalence...

Equivalence Principle: A hint on how to start! Hi, I have no idea where to start. 1. Statement Problem Let X be a non empty set with a equivalence relation ~ on it. Prove that for all x,y\inX, [x]=[y] if and only if x~y. Homework Equations For the Equivalence Relation to exist, it...

I have been trying to work this out for the last couple of weeks, but I just keep getting the Newtonian deviation in angle for a path of a photon traveling from x=-∞ to x=∞. At first I tried putting the actual path into a computer simulation, transforming back and forth between the hovering...

I have been reading my books section on the weak equivalence principle over and over again, I think I understand it now, this is my understanding. Since all particles are accelerated by gravity at the same rate, no matter what they're composition or mass are, only a frame free falling with...

Hello Forum, According to general relativity, objects in a gravitational field behave similarly to objects within an accelerating enclosure. For example, an observer will see a ball fall the same way in a rocket as it does on Earth, provided that the acceleration of the rocket provides the...

I'm having a little trouble understanding the equivalence principle explanation of the twin paradox. I understand that the resolution to the paradox according to the equivalence principle is that the non-traveling twin has a higher gravitational potential energy in the pseudo-gravitational...

I've seen a lot of statements regarding Einstein's equivalence principle. Many formulate it to say that no experiment can distinguish between a reference frame in a gravitational field and an accelerating reference frame. But - isn't is true that in a gravitational field, tidal effects are...

I had a physics test at school recently. One of the questions was based on the equivalence principle, going something like this: Two clocks in a spaceship that is accelerating. One at the bottom and one at the top of the space ship. Now think that the spaceship is so far away from any object in...

An accelerating elevator is locally equivalent to a gravitational field. When this is applied to light, it is seen that a horizontal beam of light in the accelerating frame curves and the effect is same in a gravitational field, but wouldn't this violate the constancy of the speed of light?

Why do we say that Galileo's experiment at Pisa is an illustration of Equivalence Principle? All we know is that G* (mass of earth)*(gravitational mass of object)/(R^2) = (intertial mass of object)*a Therefore, a=G* (mass of earth)*(gravitational mass of object)/(R^2 * (inertial mass of...

Hello, I'm having some issues with Love's equivalence principle. I'm studying Balanis' "Antenna theory" (1997), here's a (legal) fragment of the section in question: http://www.uniroma2.it/didattica/ap1/deposito/02_2-Balanis-Equivalence_Theorems.pdf I'm trying to understand the following...