Relativity

Hi everybody! I am new here and my mother tongue is not english, so please dont kick me if make spelling mistakes Now, to the topic: With the recent news about the finding of gravitational waves there will be plenty of discussions about it. I have a very specific question, that why I am not making it on other threads about it. I just have a very small idea about the Theory of Relativity (the kind of things that a common person will learn if read some book about that), so my question may look like silly: didnt we already had a proof about gravitational waves with the Gravitational Lens effect? I tought that gravitational lens already was a proof about the exist…

I was looking at the way they draw BHs merging and I think are they drawing it wrong. If things orbit along a geodesic how can they draw the spacetime curvature as two pits. Do the BHs have a common center of mass (the barycenter) and shouldn't that point be the deepest part of the warp?

Force without acceleration in S.R. & acceleration without force in S.R. & applied force is less than acting force in S.R. STEP 1:-This problem can easily be understood by following paradox. {Before starting this paradox, I want to put some relativity formulae’s In any frame for force in X-direction Fx = d/dt( y. mo. ux) where y=(1-u2/c2)-0.5 After differentiation, we get So, Fx=y. mo. ax+y3 mo. (ux/c2} (ux ax+uy ay+az az) ------(1)} Now, Paradox:- On frictionless platform, object is moving with constant velocity ux in X-direction & only magnetic force is acting in Y-direction & there is acceleration in Y-direction only & Fz=0 If we…

I'm aware, (or at least it's my layman's understanding), that there is no such thing as a universally agreed point in time known as the present between any number of independent observers. However, is it correct to say that any observer has a current point in space time, which could be marked as the present, by which the distance to all other points in space time could be measured against? Is this still allowed if the observer moves in space-time himself, or doesn't it matter since in the relativistic sense he isn't moving, but everything else is? If someone defined the point in space time as the present, being centered on the self, does that point then become th…

This is probably going to be a bit controversial, but I find this a great forum so I am hoping things go well. Fifteen years ago I had a profound realisation about the nature of reality, this realisation is basically a theory of everything (actually its just a space/time theory). Now I realise what I am saying here and it is either one of two things: 1 - I am insane (most likely). 2 - I am proper genius (highly unlikely). Now if its the first one, there might be a few laughs and that will be the end of it. Not very interesting outcome. However, if its the second one, then this is not only good for me, its good for all mankind. Very interesting outcome…

Specifically these Minkowski diagrams. It has taken me a (long) time to realise that these are actually"correct" models of "reality". (I thought they looked too "childish" to be for real) but I have since come to understand that they are fully predictive (am I right now?) Anyway I have a specific question about them. Are there any circumstances when these diagrams do not "work" (within the theory of Special Relativity) ? In other words is their applicability fully co-extensive with that theory?

Could the principle of equivalence explain the apparent rate of expansion in the universe so that we don't need DE? I'm not a physicist but I'm good with logical constructs. The equivalence model for a body at rest on the surface of the Earth is a body accelerating at 1g through inertial free space. The property of equivalence has proven to hold up well under GR, so let's assume for now that it's true. I think it's easier to see if we just use equivalence to model gravity as the acceleration of local spacetime in towards the planet, as opposed to curved spacetime. We have always just thought of the inertial free space equivalence model as a hypothetical an…

Fizeau experiment and Sagnac effect are explained completely and correctly only using special relativity (Lorentz transformations), although the speeds involved are far smaller than c (the speed of light in vacuum). Don't you think that we should have a "classical" explanation for them? Do you know any? As I wrote here, Sagnac effect is explained in a classical way only when light is travelling through vacuum or air. When the refractive index is greater than 1, SR is used.

Can we define speed of nonsimultaneity stream so?: t'=(t-v*dx/c2)gamma vn=gamma(0 -v(v*dt))/(c2dt) vn=gamma*v2/c2 vn is speed of nonsimultaneity stream

One of the citied proofs of relativity is an experiement using atomic clocks to prove time dialation. My question is, how do scientists know this is time dialation and not the atom simply raising or lowering the speed of their 'tick'?

Geodesics, free fall and the equivalence principle. How can I relate my Newtonian understanding of physics with the principles of general relativity? Is there no such thing as centripetal force, inertia and gravitational potential energy anymore? When I'm jumping in the air am I on a geodesic?

Is it possible to puncture the fabric of spacetime? In the demonstrations the ball rolls around the depressed well caused by the more massive weight, and you could imagine the rubber sheet tearing on occasions. Could such a thing happen in nature? What would be the consequence of a mass not following the geodesic? What made me ask this question was in elliptical orbits the object does not go around the circular sided well of the fabric of spacetime. Is it taking a sloped path then or does it puncture the fabric of spacetime?

Would hawking radiation preferentially select the opposite charged particle of a pair and gradually reduce the charge of the rare case of a charged black hole to neutral? For instance a positive black hole would preferentially emit positrons and consume electrons, and vice versa. Conversely could a statistical imbalance of absorption of electrons, since each pair creation event is an independent trial, lead to rather than black hole evaporation, black hole growth and the change over time from a non charged black hole to a negative black hole? Or would the law of large numbers forbid this? Isn't there still a possibility, given that there are probably billions upon bi…

Since the space is curved between the two black holes is the time that light takes to get by increased or does the equivalence concept mean that since the gravitational acceleration is zero there is no affect on the time the light takes?

It is written,(e.g. here), that the detected waves originated from a merger of two black holes, originally having masses of 29 and 36 sun-masses 1.3 billion years ago. I can imagine that the form of the signal shows what kind of event it was. But where I have difficulty is understanding how they know this moment and these masses. Would two lighter black holes closer by not give the same signal? If one compares this with all the difficulties one has to gauge the cosmic distance ladder, it is quite astonishing. Can somebody explain how they know this?

Is this theory described in this link Which is being removed due to a rules violation respects special relativity conditions.

Can anyone give us a quick reminder what happens to the conservation of energy in general relativity please? It might be worth exploring as a separate topic.

Can I go a little off topic? I have heard (if I recall correctly) that the effects of "gravity" can be derived simply using Special Relativity. If that is so , can Minkowski Space-time diagrams be roped in to illustrate how objects move in the vicinity of mass and energy?

I have seen this visualisation expressing the suns gravitational effect on our planet quite a bit: However, what I don't see, and what this question asks, is how does this work with the gravity and objects on the earth, me for example? I was hoping somebody could provide a link or explain this. Thanks.

Just curious what the time dilation and length contraction equations would look like in a system based on: v = c - vNormal for finding velocity. I was thinking along the lines of how we convert to Kelvins. Wondering how things would look if we did something similar with velocity.

i dont know much about science, but i remember reading something about atoms vibrating, i read that if atoms vibrate slower then the speed of light then they become physical and if they vibrate faster then light then they become un-physical is this true?i thought nothing can move faster then light. then i really thought about it and ran into a problem i cant figure out, and google doesnt have the answers either its hard for me to explain but here goes, okay,so imagine the earth and our sun, we know that light does infact take time to travel from the sun to earth.(not sure exactly how long, buts thats not important right now) so now imagine that your traveling at the sp…

I feel that this is a fairly common expression but what does it actually mean? If I write the phrase "The surface of spacetime" what does it describe? As far as I have been able to understand ,spacetime is a mathematical construct and consequently am I right to think that "the surface of spacetime" is also a mathematical construct and not a physical object as such? Is it a region where things happen? Is the event horizon of a BH such a region? Are there other examples? I think I have been told that you can make a surface mathematically in spacetime by holding one of the variables constant. Would this be right?

If special relativity is literally true one would be able to traverse the entire universe within a lifetime by travelling at less than the speed of light and return to find this galaxy long dead. If one could travel at the speed of light then the universe would not even exist. And if one could travel faster than the speed of light one would have returned to this galaxy before having actually set off

Either space is relative to time. Or time is relative to space. Now the Minkowski block universe model makes no distinction between past and present and future. This is why quantum mechanics makes no sense. But if space is made relative to time then it is at least being made relative to something that is actually known to be physical