Relativity

Hardly news shattering that there is a mass -energy "equivalence". Was Einstein the first person to show this ? Can someone perhaps give a little detail (or a rough resume) of how the two are connected? Is it interesting that c ,which is described as a "conversion factor" between space and time (have I got that right?) appears to fill the same or a similar role between mass and energy?

But Einstein told us that x=0, then Who can help me explain where he was wrong? I am in a perplexity. https://www.scienceforums.net/topic/113238-whether-the-special-theory-of-relativity-needs-space-time/

Whether the special theory of relativity needs space-time First, the space-time here refers to the space of the t moment, because the quality will distort the space, and the space at different times is different. Common view: Both the special theory of relativity and the general relativity are verified by experiments and are correct theories. Different views: Your mainstream view is that it is only necessary for AB to refer to each other to explain physical phenomena with relativity theory. My point is that it is necessary to use SPACE-TIME as a reference to explain physical phenomena in relativity theory. Present si…

- Yes, because.... - No, because.... Can mass fundamentally impact space and time itself?

The Alcubierre Warp Bubble Drive works on the idea of expanding space behind the ship and compreesing it in front of it, performing a sort of "Space Surfing", to trick the light speed barrier and relativistic field. Even though the ship doesn't move by itself, it only manipulates the spacetime around it, isn't that the same as moving fast, what makes this system still prone to time dilation? Even it's updated version, where instead of warping just an area around it it compreeses all spacetime in front of it till the destination local in space and expands everything behind it till it's original location, thus creating a wormhole and all the ship has to do is cro…

Excuse my ignorance first of all. I'm just a guy who never really paid attention in any science class, but now, a bit later in life, I've become very interested. So, (and I may even be starting from a poor understanding) but from what I get, speed, especially light speed, if you're travelling at that speed, has an impact upon your experience of time. Before I go any further, just want to be sure I have that right!

To overthrow a wrong theory, its difficulty lies not in logical reasoning and mathematical calculations, but in the fact that you have moved their cakes.

Let‘s see the essence of things. What is speed? Firstly speed is a relative value which can only be described by reference to something. For example: Tom and jerry run race, TOM faster than JERRY 2 m / sec. How does this figure come up? TOM speed-JERRY speed = 2 m / sec, their speed reference is runway. If the race field is in space without any other reference point, including space itself. TOM's reference is only JERRY . Then you will never know how fast TOM JERRY is. Because you don't know their speed, you don't know how much time they expand relative to our planet, and you don't know who TOM and JERRY are fast or slow, you can only observe them aw…

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The derivation of the special theory of relativity and all the conclusions imply a reference object, which is space. The twin paradox is very easy to explain. Why don't everyone see the existence of space? The special theory of relativity is originally a paper that the middle school students can see, but many scholars who specialize in physics are unable to explain it. Why? Because everyone ignores the existence of space…

Above is the Wikipedia Drawing for the Ives-Stilwell test. (I assume there is no copyright problems with taking stuff from Wikipedia.) I have seen a few (five or six) videos on the Michelson-Morley test that explained the basics either in graphical or simple word form. (I think one of them was by Neil Degrasse Tyson.) Easy to understand. And so, I think I understand the physical makeup of the Michelson-Morley apparatus. I haven’t had so much luck when looking for easy to understand videos (graphical or verbal) on the physical makeup of the Ives-Stilwell apparatus. Does anyone here know of one? Can anyone here make one? (There is a gap in content on the Inte…

http://www.bbc.co.uk/news/science-environment-42655685

When is it flat ? Is it when two observers are at mutual rest or is it when there is no presence of mass-energy ? Is flat spactime an idealization (a limit as curvature tends to zero for the two above reasons) and is curvature the "default" description? Is the universal speed limit "responsible" for spacetime curvature or are they separate phenomena? Do we need to specify "spacetime" curvature or does "curvature" or can we refer to it simply as "curvature" ?

https://phys.org/news/2018-01-space.html By shining a laser along the inside shell of an incandescent light bulb, physicists have performed the first experimental demonstration of an accelerating light beam in curved space. Rather than moving along a geodesic trajectory (the shortest path on a curved surface), the accelerating beam bends away from the geodesic trajectory as a result of its acceleration. Read more at: https://phys.org/news/2018-01-space.html#jCp :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: the paper: https://journals.aps.org/prx/abstract/1…

I understand how in free space, c is constant. And if I travel at let's say 0.5c and turn on a flash light I will record that the light is traveling away from me at c. I was hoping you could clear up the scenario that I was thinking of below Let's say we have two stationary satellites that are located exactly 1 light hour away from each other and they exactly 1 light hour away at all times. Satellite 2 starts shooting a light beam once every minute directly towards Satellite 1. A rocket starts traveling at a constant 0.6c (let's say) from Satellite 1 directly towards Satellite 2. Would the rocket also record the "frequency" of the light beam signal once ev…

This is potentially really dumb, especially the way that I am going to formulate it but please go along with me. I was reading a different thread (Time and speed and how speed impacts time) and I have a basic understanding of concepts like the Twin Paradox but was wondering if let's say Taz would spin on the same spot on the ground at a respectable speed close to c for a few minutes, would it have the same effect as if he would travel in a rocket in space and he would have basically traveled in the future when he stops? (I mean if his twin that did not perform the spin motion age more?)

I found one meter is equal to second ^4 can anyone explain what does this mean?

In the experiment by Hafele & Keating to prove time dilation the frame of reference for the tests was assumed to be connected to the center of the Earth but I assume it was not rotating with the Earth. Why not assume it was connected and rotating with the Earth?

If we set an observer at the centre of a massive body** ,how will that observer create a geometry so as model potential events? Is this even a valid thought experiment? Suppose the observer (call him O ?) wants to draw a circle or the surface of a sphere from his stand point the relationship of pi to the radius will not be Euclidean ,will it and depending of the ratio of the mass concentration to (what?) that ratio will approach or depart from that Euclidean ratio. Can a complete geometry be created for O and will it be easy for him to understand or is Euclidean geometry the only easy geometry? Apologies in advance as per usual f…

On the radio I heard the explanation of a scientific writer about measuring gravity waves (or better: space waves). He told that in principle one could not measure these with a ruler, because this would follow the wave (therefore it is measured with light). However I also read that while the universe (space) is expandig, that matter does not expand in the same way because the forces between atoms is much larger then the expension forces of space. But to my understanding a gravitation wave is an expension/shrinking of space in sinusform. So why would a mechanical ruler follow these waves?

Lately I've been interested in investigating the more intricate parts of special relativity beyond what is readily apparent on wikipedia or physics 101 videos. So, besides mathematical treatments, I want to investigate the extensive experimental support that has been built up for special relativity over the 20th and 21st centuries. I have had my eyes on Y.Z. Zhang's Special relativity and its experimental foundation seen here on amazon. Does anyone else have any other suggestions on further choices (Books and Papers alike) or comments on the viability or quality of the book above?

Does anyone know any evidence besides time dilation and Lorentz transformation that support the correctness of the Minkowski spacetime model? Thanks!

https://www.math.ku.edu/~lerner/GR/Geodesics.pdf A nice paper, on the dynamics of the geodesic in relativity.

General relativity describes gravity as a curve in space-time. In a curved space-time, an object moving in a straight line and at constant speed will, in normal space, appear to accelerate along a curved path. So curved space-time is equivalent to the accelerated shrinking of normal space over time. How then can an object have a constant volume while the space it's in is constantly shrinking? In order for matter to keep it's volume, either: 1. space is flat and gravity is the curving or shrinking of something other than space. ...or 2. all matter is expanding at precisely the same rate as the space around it is shrinking. …

I think I may have heard that Special Relativity is able to cope with accelerating frames of reference. If this is correct is it also possible for Special Relativity ,allied simply to the Newtonian formula for gravity -as being inversely proportional to the square of the distance between centres of mass of 2 objects -to actually make predictions that are as good as GR? Suppose the internal mass density distributions of Mercury , the Sun and the other bodies were known accurately enough could the predictions of Mercury's perihelion precession be calculated as accurately as was done by GR ? Since Special Relativity would be applicab…

Very detailed, very good paper. It even goes into some detail why gravity is classed as a pseudoforce, something a bit rare these days but pertinent to unification attempts, or failure, using a better word. http://www.blau.itp.unibe.ch/newlecturesGR.pdf