Relativity

if space ship travels faster then light but because relativity it moves at certain speed then compare its speed at any object moving so u notice in theory it just travels at relativity theory so time stops for him and clocks run slower compared toout side time from out side looker it seems he is traveligfaster then ligt but in reality he just bends nature law of c as fastest speed so space ship is c and observer is another c and then all variables how u measure ship speed is allways c

imagine a man in a vehicle moving with a speed near the speed of light ,if he looked through the window ,he would see things with smaller dimensions, at the same time the window's area will not change (it is moving with him) . now, what will the man see in the remaining area of the window ?

I'm reading a paper and the author uses some "Lagrangian techniques" to go from ds^2 = -(1-\frac{2M}{r})dt^2 + (1-\frac{2M}{r})^{-1} dr^2 + r^2(d\theta^2 + sin^2\theta d\phi^2) to 2L = -(1-\frac{2M}{r})\dot{t^2} + (1-\frac{2M}{r})^{-1} \dot{r^2} + r^2(\dot{\theta^2} + sin^2\theta \dot{\phi^2}), where L is the Lagrangian. Can someone explain what the step between these two equations? PS: I don't know how to make the latex code work here.

So I was thinking: you have one measuring device "A" which contains an entangled particle, another measuring device "B" which contains a particle entangled with that of A and C, and of course the implied third measuring device which contains entangled particle "C". A is kept on Earth, B is in the vacuum of space, and C is put near the event horizon of a black hole with at least 5 solar masses A measurement is made, technically the disentanglement is "instantaneous", but you can't have a universal "time" that something happens, so how do we get around this dilemma? Let's say device B made the measurement. Could device B say that it happened at the same time both on Eart…

We see only 3 dimensions because we live in a 3 brane world. What is a 3 brane world?

Guys, does anyone know which affine parameter should I use to study spacelike geodesics? I mean, for timelike curves we use the proper time. I've read somewhere that I should use the proper distance. Is it correct? And why (or why not)? Thanks to all.

canu think first traveling at certain speed any speed and then consider whats physic equation for it then thinkof traveling faster then light and do equation for it WITHOUT comparing it to c or e=mc^2 so u just think it solely as travelinng at certain speed without comparing it to c

first thinkof what happens if u ride a beam of light then think of what happens to other light beams aroud it then think ofout planet and how far are other solar systems and how long does light take to travel from them to here? and then opposite from here to there and ?dont it mean that we are center of univer ? cant be right ?

1. Hi ! , tI If, according to General Relativity, bodiesfall ( or,rather,move ) towards the Earth not due to a “ force” of gravity pulling down on them but simply because they naturally follow the geodesics of curved space-time and can therefore be viewed( I suppose) as moving in uniform motion, how come they are still seen as moving ( falling) at an acceleratingrate? Indeed their acceleration rate ( in the sense of an increase in velocity) is accurately measured at 9.8 m/s/s. My question may sound naïve to some, but may be I have reached the limits of conceptual understanding, without using maths, in which I have little familiarity beyond college algebra,…

In a specular, read in a newspaper, written was about an explorer of a new element that confirms Mandaleef Table more and more .. 2 months ago. He added it's half-life time reveals properties from the past. I wonder; "Are they still trying to acquire positions and minds like that?". Thanks not to answer. Welcome for any side notations Amr Morsi.

So I was looking through Wald when I noticed his definition of the stress-energy for an arbitrary matter field: [math]T_{ab}=-\frac{\alpha_M}{8\pi} \frac{1}{ \sqrt{-g}} \frac{\delta S_M}{\delta g^{ab}}[/math] where [math]S_M[/math] is the action for the particular type of matter field being considered, and [math]\alpha_M[/math] is some constant that determines the form of the Lagrangian for the coupled Einstein-matter field equations: [math]\mathcal{L}=R\sqrt{-g}+\alpha_M \mathcal{L}_M[/math] For example, for a Klein-Gordon field we take [math]\alpha_{KG}=16\pi [/math], and for an EM field we take [math]\alpha_{EM}=4[/math]. Now, my question is whether or …

If two objects are zooming past each other in opposite directions at the speed of light are their combined speeds not 2 x the speed of light? I mean forget transformation of coordinates and all that. Just thinking physically about two objects travelling past each other.

When mass is added to a black hole, by the consequences of mass being added, the shape of the event horizon changes with a small bulge then eventually levels off to form a perfect sphere again as the mass approaches the singularity inside the black hole. However, from outside a black hole, theoretically time is stopped at the event horizon. So, a problem I have is how do we measure the mass of a black hole changing when theoretically we would never measure mass entering a black hole due to the effects of time dilation? How could the change in it's gravitational field be measured by an outside observer as soon as a piece of matter entered the black hole from its own frame…

I was thinking of the hypothetical situation of someone going away from Earth on a spaceship travelling close to the speed of light. Are there any simple formulas for calculating the time dilation of their trip? For example, say the ship is going away at 1 c for 2 days (ship time), then comes back. Is it possible to calculate how much time has passed on Earth? If we stay on Earth and watch the ship go away, and it comes back after exactly five years, is it possible to know how much time has passed aboard the ship? If such formulas (intelligible for a layman not too well versed in heavy physics) exist, I'm assuming they'd include the speed of light? If so, what…

photon A<----[light source]---->photon B Two photons are ejected from a light source at the same time, in opposite linear directions, in a vacuum. They are named photon A and photon B. The light source is stationary and Photon A travels at c in a westerly direction and photon B travels at c in an easterly direction. Question A: Immediately after being emitted from the light source, is photon A travelling at two times c relative to photon B? In regards to question A: If the light source is stationary, then relative to the light source then the answer should be yes(Photon A is travelling at 2 times c relative to photon B from the light sources point of v…

Hi all, I was just was wondering how relativity would view a system consisting of a massive, large radius, rotating solid. Now I'm ignoring the possibility of gravitational collapse, and I'm unsure if doing so affects this thought experiment. Anyway, as we increase the rotational speed of the object, the matter at the "equator" of the sphere would approach the speed of light much faster then the matter on the interior of the sphere. And as we know, the closer you get to c, the more time dilation you get between the center and surface of the object. Would this cause a "swirl" effect within the structure of the object, due to the dilation of time between the center…

I must admit my understanding of relativity is not great but here are a couple of ideas that have been puzzling me lately. A)If I build a particle accelerator in the shape of an oval. At one side the plasma is accelerated to near the speed of light and on the opposite side the plasma is decelerated back down to less weird speeds and fed back into the accelerator. If these components are efficient most of the energy I put in is the accelerator on one side is recovered in the decelerator on the other side and recycled. But the plasma is going at different speeds at the two curved ends of the oval, according to Relativity the protons traveling near the speed of light have…

According to the relativity, when you travel around 99.999999...% of the speed of light, you would be a Black Hole. V------------->C mrelative------>infinite Fg------------>infinite Fast moving Black Hole. At the fast moving state, this gravity force relationship, Fg=mrelative g is uncertain. But, the high energy density (energy/volume) can make the object to be a Black Hole.

As I understand it, as an object approaches the speed of light, time relative to the near-luminal object is said to slow down, but at a speed near the speed of light, the speed of light must still be the speed of light to any observer! As I understand it, somehow for some random reason, the relative distance between two objects increases the more you travel near the speed of light as to cause light to always be measures as traveling at the speed of light. What exactly causes this distance increase? The kinetic energy to accelerate something to near the speed of light has relative mass and therefore distorts the local fabric of space in such a way that 4 dimensional model …

The light-clock thought problem is used to demonstrate time-dilation. From the diagrams, in addition to the accepted assumptions, we can derive the time transform. Here's a typical diagram: http://galileo.phys.virginia.edu/classes/252/srelwhat_files/image017.gif It has always bothered me that it assumes we, as observers in the moving frame, actually see the beam bouncing between mirrors, but we don't. Neither the relative position of the observer nor the process by which we observe the beam are ever clear. Also, the diagrams seem to conflate an observer at the origin of a moving frame with an absolute frame in relative motion - the aether. Let's assume the l…

The Bianchi identities along with the EFE's with zero CC imply: [math]\nabla_{\nu} G^{\mu \nu} = \nabla_{\nu} T^{\mu \nu}=0[/math] This implies that, for arbitrary [math]\xi_\mu[/math], the following holds true: [math]\xi_\mu \nabla_{\nu} T^{\mu \nu}=0[/math]. Therefore: [math]\nabla_{\nu}(\xi_\mu T^{\mu \nu}) = T^{\mu \nu} \nabla_{\nu} \xi_\mu[/math] Now let's say we're considering a free point particle traveling along some worldline with stress-energy given by: [math]T^{\mu \nu} (s) = m \frac{dx^\mu}{ds} \frac{dx^\nu}{ds}[/math] If we integrate both sides over some region containing the worldline and allow [math]\xi_\mu[/math] to vanish a…

Hello! I have Christmas present to you: on-line Special Relativity Mass Calculator http://www.ultimate-theory.com/en/2012/12/26/special-relativity-mass-calculator It takes rest mass m0, velocity and speed of light as parameters, in units you want, and calculates final mass. It's working with floating point precision of web browser - it's using JavaScript to calculate mass. ps. It appears that the latest version of Chrome is buggy and there is need to click Calculate button. In Firefox it's immediately calculating after change of value.

Isn't matter simply highly condensed space? It seems a lot of people describe them as separate phenomena.

Are two photons generated in a hypothetical accelerated relativistic reference frame still touching due to Lorenz contraction despite being separated by large distances.?

We have three Mass m-M-m 1 distance m-M = 150 000 000 km (Earth - SUN) 2 M>>>m mean that big mass M is main gravitation wave source 3 mass m speed V=220 km/s 4 mass M speed V = 220 km/s Why gravitation waves will first hit mass m left not mass right ? ( what is the reason different distance for gravitation waves between mass m left and M or m right and M ) Why when I'm pushing my finger mass m left and mass m right my finger not feel the same Inertia ? TWINS BROTHERS we have two atomic clocks one is near mass m Left and next is near mass m right TWO BROTHERS THAT KEEP ATOMIC CLOCKS TRAVEL WITH THE SAM…