Simultaneity Definition and 298 Threads

All of the statements of Heisenberg's uncertainty principle that I've read seem to state that there is a fundamental limit on the precision to which you can measure the values of conjugate pairs (like position and momentum) at the same time. So is this simultaneity necessary? I ask because...

Hello, I was wondering if the following idea had been proposed in one form or another within a scientific community. Provided that the space within the singularity is dimensionless, that being 0 in length on all the axes (is it?) the following is in order. From this follows that the Planck's...

The thought experiment starts with the basic experiment shown here: http://en.wikipedia.org/wiki/Relativity_of_simultaneity "A flash of light is given off at the center of the traincar just as the two observers pass each other. The observer on board the train sees the front and back of the...

i have a question about chapter 37.2 relativity of simultaneity (pearsons international edition university physics, 12th edition) . the text besides image b sais: inside the train, mavis moves toward the light coming from the front of the train and away from the light coming from the back of...

Problem deriving "failure of simultaneity at a distance" Homework Statement I'm trying to derive the failure of simultaneity at a distance from the spatial part of the Lorentz transformation. In his treatment of the subject, Feynman glosses over the algebra/derivation and produces the...

I read some articles on relativity of simultaneity which said that the concept is a result of ONLY the finite speed of light and does not necessarily follow from the principle of relativity. I however was not convinced with the explanation. Could someone justify if it's true?

Hi All, I think that I understand (as far as you can!) the ideas behind explaining why two twins have different ages if one travels at near light speed away for a time and then returns to his twin on Earth (the return journey changing the inertial reference frame). I have a related...

While simultaneity conventions for inertial frames in flat spacetime (SR) are non-controversial, numerous questions, discussions, and debates in this forum indicate how confusing and controversial notions of simultaneity can be for more general cases. A couple of formal and true answers are...

I am trying to understand what 'violation of simultaneity' really means, and whether it has any real importance (i.e. why was it introduced?). The Wikipedia note on this (Topic: Relativity of Simultaneity): "... the relativity of simultaneity is the concept that simultaneity–whether two...

This looks more like a relativity question, so let's post it here. I try to keep it short. Alice and Bob approach each other, synchronize their clocks when they meet, then drift away from each other with relative speed 0.8c. No acceleration involved here. There is an entangled particle, Alice...

Could someone explain how the relativity of simultaneity and the doppler effect are different?

I am having a variation of the classic simultaneity experiment (Explained in http://en.wikipedia.org/wiki/Relativity_of_simultaneity#The_train-and-platform_thought_experiment) From the midpoint of a train 2 laser beams are sent to both sides of the train. The beams reach the 2 end-points of...

Relativity -- problem of simultaneity I wrote a basic outline of relativity on my blog. I think I got it right, as far as it goes: wp.me/p2ukOd-D --As I understand it, relativity says there is no *preferred* sequencing of events. Two events can be considered to be simultaneous, or one...

All, I am having a problem resolving the common examples that are used to explain time dilation as a consequence of the constancy of the speed of light. I can't help but assume that there is something simple and fundamental that I'm missing here. I apologize in advance for forcing you to use...

Chapter 9 on the theory of relativity discusses a thought experiment (http://www.bartleby.com/173/9.html) about a passenger on a train that claims that it is impossible to say in an absolute sense whether two events occur at the same time if those events are separated in space. I have...

Suppose two spaceships A (at rest) and B(moving right with velocity v relative to A) one above the other with observer X in A and Y in B,both at the middle of the their spaceship.Let two events event RED and event BLUE strike at the edges(RED at left edge) of the both spaceship when Y is just...

Einstein in his "Relativity: The Special and General Theory" ch.VIII explains that simultaneity between events placed in two predetermined places A and B can be asserted if an observer in the mid-point M sees the light coming from the two events places in the same time. In ch.VII he says that...

The common example demonstrating relativity of simultaneity is something like this: Say there is Person #1 and #2, each on their own train, in the middle of the train from both ends. #1 thinks #2 is moving, but #2 thinks #1 is moving. Lightning hits both ends of the trains. In #1's...

Ok, I want to make sure I understand this correctly. Let's say I'm moving at 90% c and pass a light bulb that is at rest with another light bulb in the distance. In the frame of reference of an observer equidistant from the light bulbs, they flash at the same time that I my distance from each...

I'm a newbie, and I've got some questions that are raised by Leonard Susskind's "The Black Hole War," a fascinating non-technical book about his argument with Stephen Hawking about whether or not information is conserved even if it is dropped into a black hole. I've read several threads and the...

Hello, There are two observers. A is stationary and B is on train. Train is moving. B is at middle of train. If B flashes a beam to front and back, and at the both end there are detectors, then what does B measure one way speed of light in both direction? Thanks.

Hi all, I'm trying to understand relativity for the first time. First of all I'm sorry for my bad English, I'll try to be as clear as possible. My doubt is the following: In my books and on many web sites I have red the thought experiment of the train and the two bolts of lightning to explain...

Say there are two observer S and S'. Let's assume that their frames coincide at the instant t=0 and that observer S' is moving to the right at a speed 'v' with respect to the observer S along the X axis. Two lightning strikes occurs at the points A and B in the S frame at t=0. The corresponding...

Hey guys, this might seem like yet another basic question, but I was wondering about RoS. The impression that I got from reading about relativity was that relativity of simultaneity was a consequence of Lorentz contractions, primarily time dilation. Someone else made the point [emphasis is...

Homework Statement Two students on the ground, separated 100m from each other, launch one rocket each vertically. The rocket explode at the same time for an observer, on the ground, that's midway between the rocket explosion. At the exact time the observer sees the rockets exploding a...

Can you give me some "real life" examples of simultaneity? For instance I know the one about the train and the lighting strikes but I was under the impression that this only holds up if the train is moving close to the speed of light. Thanks.

Here is a question which can seem stupid to a lot but it has stuck it my mind and i can not move forward. There are two points to it. 1 - The speed of light is same in all inertial frame of references. So if an observer is moving with a relative velocity 'v' withrespect to another stationary...

Homework Statement We have an observer moving along a moving train car with speed v (assumed to be relative velocity between observer and car). Two light signals are emitted from each end of the car. a)Where is the observer if he sees both signals simultaneously? b)From his point of view...

As time-dilation is stated in STR, 1.) it is an intrinsic decrease in rate of passing of time, with relative motion(radioactivity half-life change). 2.) it is non-directional, that is, time-dilation depends only on the magnitude of relative speed. Now, please consider the following...

Hi! This is the definition of simultaneity I was taught: Two events that are simultaneous in one frame of reference need not be simultaneous in a frame moving relative to the first frame. I'm wondering if this concept only applies to relativistic phenomenon, and if not, would you happen...

All the events that are connected with a particular "Event 1" by spacelike intervals lie outside the past and future light cones of Event 1. But in some other frame of reference these events which are connected to Event 1 by spacelike intervals can appear to occur simultaneously with Event 1...

in einstein train thought experiment, if two bulbs were placed, in the front and rear of a moving train. And a person A with a single switch for the two bulbs stands in the middle of the train. Near the lights are clocks which register current time, when the light glows. would the person A...

I have seemed to confuse myself after watching this video: Everything makes sense except for the bit where the video says the passenger sees the bolts at different times. How can this be justified and how do we know the passenger doesn't see them at the same time from his frame of reference?

The example our lecturer uses to illustrate the relativity of simultaneity is a light clock, where a photon is bounced between a reflector and a detector. a tick in the clock means the light has made a round trip in the clock. There are two clocks, one is orientated perpendicular to the...

Homework Statement Homework Equations http://upload.wikimedia.org/math/7/8/1/78195e8f63116bf11b2bbef574fbcc25.png The Attempt at a Solution I'm not entirely sure how to use the equations; a worked example would be very helpful!

Hi. The concept of relativity is that the laws of physics are the same in all inertial frames of reference. As a result of relativity we have the relativity of simultaneity, which says that two events that are simultaneous in one inertial frame are not simultaneous in other frames. Now...

Feynman makes an example (15-6 in his lectures) about failure of simultaneity at a distance, using the Lorentz's transformation of time. A man moving in a spaceship (system S') synchronizes two clocks, placing them at each end of the ship, by a light signal sent from the middle of the ship, and...

There are two space stations A and B which are at rest wrt to each other and separated by some distance x. Each space station has a light that randomly flashes. I am in a third space station, somewhere in the middle of A and B and at rest wrt to the other two stations. I see Station A’s...

A previous question that I asked got me thinking about simultaneity, and I have a couple of questions on the subject. Concerning the Einstein's train thought experiment. The observer on the train perceives the lightning to strike the front of the train first. So in his reference frame he does...

Hi, I was reading the book "Spacetime Physics" by Taylor/Wheeler. In their discourse on the relativity of simultaneity, the example they have used is Einstein's Train Paradox. See and also the attachment for the Train Paradox. My question is this: The analysis of what the train observer(TO)...

I have think I might have a feeble grasp on the idea that simultaneity of events at different points of space depends on the reference frame. However I was having a conversation with my friend and we were trying to figure out if there would be a reference frame where our whole life happened...

Homework Statement There's a train traveling at 0.5c when a light at the center of the train flashes. When the light reaches the front, it rings a bell. Light reaching the back rings a siren. Question is: are the bell and siren simultaneous events for a train passenger? are the bell and...

Hi there, Physics lovers. I'm studying "The Classical Theory of Fields" from the "Course of Theoretical Physics" book series by Lev D. Landau, and I'm stuck with simultaneity in General Relativity. In page 251 of the Fourth "revised" english edition, by Butterworth Heinemann, There begins the...

I am going to talk about the famous train-platform experiment where two lightnings strike both ends of the platform and the observer on the platform is in the midpoint of the two events. From the frame of reference of the platform, the light from event A (the one the train is moving towards)...

In special relativity the relativity of simultaneity is explained with the following example. We have one frame of reference - a train moving from left to right with constant speed v relatively to the embankment, and second frame of reference - the embankment itself. On the embankment there are...

Many people have difficulties to understand how time dilation can be consistent with he special relativity principle: "According to the observer on the Earth, the observer at the spaceship is aging slower, but according to the observer at the space ship, the observer on the Earth is aging...

According to SR relativity of simultaneity, the temporal order of events depends on the frame of reference from which the observer watches the events and different observers with a spacelike separation between them or at relativistic speeds won't agree in the order of events. Now , in...

Why is it that the relativity of simultaneity isn't used to explain wave/particle duality? RoS requires that matter be in different places according to the speed of the observer. All observers are equally correct. This would seem to require that particles posses a wave characteristic...

let's say a train is traveling at relativistic speed along a straight line to right, and a man is standing in the middle of the train. Both end of the train was installed a gun which aims at the man. The right-ward gun aims at the man's leg and the left-ward gun aims at the man's head. In...

Hi, I'm stuck on a couple problems from my Mastering Physics homework. #1 There are three space ships (each 10m in length,) each traveling 90m apart from the center spaceship while traveling at a constant speed of .9c. They're entering into an asteroid (215m in length) where some people hope...