Relativity

I know that this is probably me not knowing enough about the theory but I have noticed a seeming inconsistency in the theory. It follows thus: 1. Nothing can move faster than light. 2. Mass distorts the curvature of spacetime. 3. A change in an object's position changes the distortion. 4. This distortion would either have to travel, causing strange effects with the gravity of the universe and moving high-mass objects, or be instantaneous, thus in violation of one of the theory's postulates. Can anybody help me with this? I'm kinda stuck on this one.

If [math]\vec{p}_{tot} = \gamma m \vec{v} + e \vec{A}[/math], what value of the momentum, [math]\vec{p}_{tot}[/math] or [math]\vec{p}_{conventional}[/math], is used in [math]E^2 = E_0^2 + (c p)^2[/math] ? And, what if there is also an electro-static potential, too ? For small electro-static & electro-dynamic potentials, the formula [math](E - V)^2 = E_0^2 + (\vec{p}_{tot} - e \vec{A})^2[/math] seems to correspond to the classical limit.

I'm reading Leornard Susskind's book, The Black Hole War, and I came across something that contradicts everything I've heard about black holes. Can someone explain what Susskind means by the paragraph on page 151-152 of his book? In general, this section of the book is about how Beckenstein calculated the entropy of a black hole. "Recall from chapter 4 that the resolving power of a light beam is no better than its wavelength. Now in this particular case, Beckenstein did not want to resolve a spot on the horizon; he wanted to be as fuzzy as possible. The trick was to use a photon of such long wavelength that it would be spread out over the entire horizon. In other wor…

I have learned from physics articles that the speed of gravity is equal to the speed of light. I'm just curious.., could light be the reason for gravity? If not, what is the reason for gravity? Just asking... If my lack of knowledge is causing me to ask or say something stupid, I apologize in advanced.

I've enjoyed reading books by Stephen Hawking, Leonard Susskind, etc., but my lack of formal, methodical physics education has left me with a big gap in my understanding of relativity. I'd really appreciate it if you can educate me on the following... Do the relativistic effects (time dilation, length compression, mass & gravity increases) that occur when an object approaches the speed of light affect just the quarks and electrons that the object is made of or is there a region of spacetime around the entire object that has a gradient of effects applied to it? If it's a region, which I suspect because of the mass increase and therefore a gravitational field, what …

stationary charge produces electric field Constantly moving charge produces electric+ magnetic field accelerated charge produces electric+magnetic+radiation(photons) CASE 1:- Two charged masses A and B are put side by side and an observer too. All being stationary. Observer will only detect electric field from two masses. Case 2:- One Mass A starts moving at constant velocity away from observer while other mass B is stationary on the side of observer. Observer will detect electric and magnetic fields from moving mass A, and only electric field from stationary mass B. If observer starts moving at same velocity as that of A, magnetic fiel…

Hi All, I am new to this forum. I watched s Stephen Hawking episode on Nat Geo last night 04/24/2010. It was about time travel. He said "my simple translation here" that if one could travel in space close to the speed of light that one could travel into the future. For example, If you were able to travel close to the speed of light in a space ship around the Earth for lets say 1 week, then 100 years could pass on Earth from the time when you left. My question is: If this could happen some day wouldn't the space traveler who comes back to Earth be of no real use to Earth's work force since He/She would know nothing about all the new technology from the time…

CONDITION:- If a torch emits a photon with high frequency( high energy "E") another torch emits a photon with very low frequency ( very low energy "e"). Question:- Which torch will get bigger thrust in opposite direction? My Perspective:- According to newtons 3rd law both should get equal thrust because speed of light is constant no matter what the energy. <<<<Please answer>>>>>

If relativity treats time more or less as a dimension, must it then also treat the world as deterministic?

Hello everyone, welcome Consider a straight long tube CD which on conduction electro-deposition of copper takes place at the cathode (-). The cathode is in contact with a long piece of wire AB (as shown in fig 3) which is connected to the negative terminal of the battery and the anode is connected to the positive terminal. PQRS is a piece of wire or a metal plate shaped as shown and is placed near this (AB – CD) arrangement. We all agree with relativity, its two postulates and we all agree with the effects of Lorentz contraction on things moving with respect to us. but why is the effect of Lorentz contraction on moving electrons in a wire…

Excuse me as my understanding of this level of physics is not my area of expertise. It is my hope someone will be able to satisfy me with an explanation. According to Einstein's theory of relativity time slows down as you approach the speed of light relative to a stationary body. The protons in the LHC are traveling close to that velocity. So the accelerated protons will experience time differently to 'stationary' proton outside the accelerator. So how long will pass for the accelerated proton in one of our 'stationary' seconds? And is there a simple equation for calculating this effect?

The Schwarzschild Radius of an electron is ~10-57 m, whist that of ("bare", "undressed") u & d quarks is about 10x larger. Never-the-less, a pure point particle has zero radius, and, so, R = 0 < RS. Wouldn't, therefore, demanding that all particles be treated as classical pure point particles imply, that all matter is made up of mini-Black-Holes ? And, such mini-Black-Holes would evaporate by Hawking Radiation in ~10-98s. How could matter, made up of mini-Black-Holes, which evaporate in less than a Planck Time, make up (stable) matter ? (Doesn't the "smeared out" distribution of matter, in the Wave Functions of quantum theory, 'neatly circumvent such is…

In a vacuum environment where does the force come from that is exerted to fill that void. If there isn't anything there why would there be a force, or should I say energy present. It is exerted on surrounding elements, all driven to the center. It doesn't work like gravitational pull, the heavier elements sink to the bottom. In a vacuum that is filled It will tend towards equilibrium. I think I posted this in the right section.

Has anyone thought or tried an experiment with ants (or much smaller creatures) travelling at very high speed? Are they going to age slower or faster? Is it feasible? Would this be enough to prove Einstein right or wrong?

Assume the typical co-location of origins and a light pulse at the co-location with two frames in relative motion. The Relativity of Simultaneity contends if two points are simultaneous in the rest frame, then these points will not be simultaneous in the moving frame. Both postulates of SR contend light is always spherical from the light emission point in the moving frame and any point with the associated time value can be translated into the coordinates of the rest frame. So, here is the question. Just consider the x-axis. Say two points R1 and R2 are simultaneous in the rest frame. What two points in the moving frame when translated to the rest frame coo…

So this topic may be misleading... It is not as much whether the galaxies are getting further away from us at a faster rate.. it is more the question of why.. I have been watching Stephen Hawking's new documentary on the Discovery Channel and found some interesting things. First was the idea of a train moving at 99.9 percent the speed of light around the earth. If this were possible and was moving in the orbit of the earth, then if we could look inside the train the people would all be moving in extreme slow motion... to them we would be moving in extremely fast motion. For every 100 years that passed for those of us outside the train only one week would pass for …

OK I have just got a few questions. They have probably been asked before, but I have looked and can't find the answers... Question 1: I understand that if something is completely stationary, then it moves through the time dimension at the speed of light..? So if I was sitting stationary, at the centre of the universe (assuming that the universe is all that there is, and its not itself moving in some other body), then all I am traveling through time as fast as is possible? Now my question is, when I stand still on earth, I am no longer stationary relative to the universe (because of the earths movement/rotation). So what percentage of my speed of light "allocation"…

This is something that is starting to rankle my little Newtonian mind. If the universe is expanding in all directions at once like the surface of a balloon shouldn't everything in the universe be expanding as well? Therefore as the distance between stars, galaxies etc. becomes greater the stars and galaxies themselves (as well as atoms, electrons and photons inside them) become larger as well so proportionality is maintained and there is no Doppler effect? Or is it like tracing your hand, because everything expands at the same rate proportion is distorted? In other words because the distance between the stars and galaxies is so large the expansion between the objects in t…

I would like to begin this by first discussing this effect in terms of classical gravity and then move it to relativity. This will make it easier to see this very common gravity anomaly. Here is the scenario. We are in space at zero gravity. I have a closed beaker full of liquid water. I take a pipet and place a bead of oil at the bottom of the glass. Because of zero gravity the system remains that way. Next, I will add gravity. The gravity will induce the phenomena called density and cause the bead of oil to move upward, away from the center of the gravity. None of the other forces of nature, alone will cause this effect. Once we add gravity, gravity will make …

I was watching a show on PBS about the cosmos and they said that there was a particle that traveled and could only exist at speeds faster than the speed of light. I cannot for the life of me remember the name of this particle but I wonder if it is purely theoretical or there is more to it than that. How would such a particle be made and how would we detect it? thanks, Paul

i need examplees of spacetimes where the ricci scalar is constant but nonzero . Particulary i search examples of line element.

Hi. Im having troubles getting this concept, and it would be really useful if someone can help to clarify my understanding... Referring to Einsteins thought experiment involving the train and two flashes of lightning hitting the track: The reason for these events being simultaneous on the platform, but not on the train, is because the light takes a finite amount of time to reach the observation point. During this time the train has advanced towards one event and away from the other, therefore one flash will hit the observer on the train before the one chasing it. An explanation of this phenomenon introduced the relativistic length of the train, but this does n…

this whole thread assumes that momentum is the same as movement through space-time, please tell me if i am wrong. I was browsing around some articles on particle physics and relativity and the like, and I stumbled across a short article on Energy-Momentum Relation. It stated that mass and energy are proportional (which I already knew), but then that Energy, Mass and Momentum are also proportional. i found this intruiging, but didn't expect to discover anything exceptional. the equations stated that: (i can't use superscript characters in this, so ^ indicates superscript) E^2=m^2c^4+p^2c^2 where E is the total energy, m is the mass, p is the momentum and c is the …

Hi all, I've been thinking about this for a while and can't get it to add up in my head. I know that according to Mr Einstein, a jolly clever chap by all accounts, nothing can move faster than light. This includes information, as described by light cone diagrams. However, thinking way way back to school, I remember my physics teacher telling me that electricity actually travels instantaneously. The analogy he used was that an electric current in a wire is like a smarties tube full of marbles: If you push another marble in one end, a marble comes out at the other end. i.e. if you push electrons at a power station, the electrons in my kettle move instantly becau…

We all know that massive objects exert a gravitational influence on other nearby objects. This obviously means that gravity works across space. Should the same not be true of time? I've heard it said once that there's a principle that states that space and time are analogues of each other, meaning that whatever is true of the one is also true of the other. But what does it mean for an object to exert gravity across time? To me, it could mean nothing other than that an object exerts a gravitational force on itself in its future and past states. But what does that mean? To me, it seems it could only mean the same thing that it would mean in terms of space. In terms of s…