Relativity

Hi guys, in most relativity articles on the internet, and in books, relative simultaneity is always mentioned in the context of special relativity, and that it depends on the state of motion of the intertial reference frame (or observer). But curiosity has brought me another question, which is related to general relativity, and its take on the relativity of simultaneity. The most known effect on time which is related to GR is gravitational time dilation which is mostly discussed when people talk about GR, but does GR change anything (or add anything) to the definition of relative simultaneity in special relativity. By this, I mean any new criteria or conditions wh…

If you are in empty space, nothing around. Just a waste space of nothingness. You could be traveling at the speed of light, casue you don't have anything relative to you. How would you know? If 1000 people without the knowledge of time or clocks ended up on, say a space station without anything relative to them, how would time look like to them? How would time evolve?

An analogy used to describe relativity doesn't make sense to me. The clock analogy. Where you have a man, at rest, holding a clock on earth. And you have another man holding a clock in a rocket blasting away from the earth at ?thousand Mph. From the perspective of the man on earth, the rocketman's clock would slow down in comparison with his own clock, at rest on earth.??? Isn't it true that there would be no change in time due to the perspective of the man on the rocket? To himself he is the one at rest and it is the clock wielding earthman, who is blasting away from him at ?thousand Mph. Taking in the perspectives of both men, wouldn't the supposed change in the eac…

I am looking for modern science fiction films (1995-today) that use aspects of the relativity theory. Interstellar is already in my list. I am thankful for every recommendation.

Hi everyone, Suppose that there's an electron at rest removed from all gravitational sources and any other fundamental particles. There's an observer who is revolving around the electron at a distance of [math]d[/math]. But, due to lack of reference points, the observer cannot say with certainty that he is revolving or the electron is. He assumes that the electron is revolving. According to the Larmor's Formula, the observer will find energy being radiated out by the electron since he observes it revolving. But, how can the electron radiate out energy if it's not revolving? So, will the observer record no energy?

I know I might sound stupid, but I'd wanted to know if anyone knows an author who has written a hypothetical mathematical formalism for speeds greater than that of light as an extension of the ideas of Einstein special relativity. If so please share links, 📚 or references of such ideas.

Imagine observers A & B are in uniform motion in freespace and seperated by 1 lightsecond which is d = 299,792,458 m But if we transmit a clock signal with a funtamental frequency of 300MHz for exactly 1 second: f = 300,000,000 Hz λ = 1.0m exactly another words, in 1 second we transmit 300,000,000 lightwaves so the speed of light tells us the wave front traveled a distance of: d = 299,792,458 m but the sum of the wavelengths add up to d = 300,000,000 m So either light is blueshifted at v=0 or 415,084 bits of information was destroyed. So what's wrong with this picture?

Hi everyone. As this is my first post, I should say I am a retired non-scientist/mathematician, so I appreciate reasonably non-technical responses, please. Richard Muller, “Now” (P.169) says: “In the initial Big Bang, before the appearance of the Higgs, all particles were massless.” 1. Is this the generally accepted view? 2. What about mass that is not dependent on the Higgs, would that have been negated by the extreme temperature? 3. I assume he is referring to a quark-gluon plasma. My understanding is that gluons are massless, but quarks have mass. Would that not apply in a plasma?

Suppose there is a wheel that is revolving upon its axis and we imagine that it is made up of very many electro magnets(like a leggo construction). Its shape is that of a conventional wheel with perhaps 20 spokes and a circumference -all made out of the same material , these very small electro magnets which are all the same size and shape so far as is possible. As the wheel turns it maintains its shape , held together by the magnetic force between its components. What happens when the electricity is cut ? I am wondering what shape the wheel adopts as it starts to disintegrate? Do the spokes arc in the direction of the previous (before the power was…

Am I correct in saying that as you approach the speed of light distance contracts? If this is true then at the speed of light the length of a finite universe would be zero and light would be instant. I do have a theoretical solution to this dilemma which also explains the dual nature of light as both a wave and a particle but would appreciate learned comments first. Thank you.

I have heard that intrinsic curvature does not require a manifold (is that the correct term?) to be embedded in another dimension for its curvature to be apparent ( and calculable ) to an observer inhabitant. Parallel Transport on a globe is adduced as an example whereby a dweller on the surface can test for intrinsic curvature. How can this be the case if as is described the vector which is being transported lies in the "tangent plane". ? Does this tangent plane not lie in a higher dimension ? How is it possible to have a tangent plane on the surface of a globe that does not presupppose the existence of an embedding 3rd dimension? To carry on …

This news just in from a Feynman lecture http://www.feynmanlectures.caltech.edu/II_42.html "Suppose we take the earth as an example and forget that the density varies from point to point—so we won’t have to do any integrals. Suppose we were to measure the surface of the earth very carefully, and then dig a hole to the center and measure the radius. From the surface area we could calculate the predicted radius we would get from setting the area equal to 4πr24πr2. When we compared the predicted radius with the actual radius, we would find that the actual radius exceeded the predicted radius by the amount given in Eq. (42.3). The constant G/3c2G/3c2 is about 2.5×1…

We have time dilatation caused by simple relative movement where each observer views the other's clock as moving more slowly. Then we have time which is altered by acceleration or gravity where one observer sees the other's clock as moving slower and the other sees the opposite effect. Are these the only two processes* where observers see each other's clocks move at different rates? Another question : when 2 objects separate and after a period of time are brought together ,is the degree of difference in the reading of their clocks dependent on their respective velocities over the course of the round journey? If acceleration is employed over the…

Just a thought from one of today's bottom science fiction authors: We are mid-inner-sphere of the cosmic microwave background, as is our neighbor four point nine billion light years away. being inside we both see everything that was ever created since the big bang. Yeah, you might want to read that again and let it soak in a sec. . . From you're perspective, You are the center of the observable universe, because you are the one observing it. Take a big step in any direction and the universe will expand in the directions needed to accommodate the new position. To understand this is the beginning of time travel and an understanding of dark energy.

It seems to me (a very recent realization ) that simple relative movement causes observers to view the clocks in relatively moving frames to run slower. I had (wrongly?) assumed that this property was a function of speed but I now think that relative speed merely increases the magnitude of the effect-it does not cause it. It is simply enough for bodies or frames to be in relative motion for time dilation to be the "order of the day". Since I would argue that everything is of necessity in relative motion ,is it fair to say that clocks will never agree but it is only the degree to which they disagree that can be determined? Is this simply a philosophic…

Suppose we have a medium which limits the speed of light to some constant speed -a fraction of c ,10% as an example.(ie c/10) Will any observer in this medium ,in any inertial frame of reference see light in this medium moving at this same speed? Is it possible to extend the question to an observer outside the medium -an observer in a vacuum for example ,again moving wrt the light source at a constant rate?. As usual ,I hope my question "makes sense" and is interesting.

Are there examples of Negative Spacetime Curvature? Is it a term that only applies to the universe as a whole or are there local regions when spacetime curvature is negative (I think there are local regions where it is positive -such as planetary systems and galaxies?) Might it apply to the interior space left behind by an explosion such as a supernova ?

I think I have heard that it takes aeons for light to progress from the centre of the Sun to reach the surface. At that point I imagine it moves instantaneously at the speed c Are we talking about an expanding sphere at this point? Countless billions of expanding spheres of light ? Are these spheres perfectly symmetrical or are they "oblong" at the point where they emerge from the medium of the Sun into the vacuum of Space? Can I take it that the spheres do no interact with each other? Is the picture I have in my mind of porridge bubbling any help at all? Or the Icelandic hot springs/geysers perhaps. I hope I posted in the right s…

Do you have an images of what a light cone of a particle B might look like, when measured in the frame of another particle, A such that A and B are in substantial relative motion?

So i have an interest in information from mediums, whether you believe mediums are real or not is not up for debate, the information presented though is. That's why i felt it best to bring it here and see if you guys with the scientific backgrounds can make sense of it and actually get some new ideas from this or if it's just complete crap. Please don't respond with, 'it's spirituality so it's bs, im not even reading it' Just take a look and tell me what you think. Thanks. This is a question and answer transcription between spirit in the afterlife and medium. ST: I mentioned spirituality as the environment of beings in non physical matter compared to e…

What is the relationship between these two concepts? The former seems to be made up of lines and intervals along the 3 spatial and 1 time axes. When all the lines are drawn in, it gives a 4D ""grid" which can be as finely defined as you like (so long as you stay in the macro level) As I see it the volume demarcated can (should?) be a finite volume . At intersections along the grid there are points where a spacetime event may take place but I think that these points may also be "empty" The spacetime manifold seem to me to represent the same volume but it only contains the points of intersection of the "grid". It is as if these intersectio…

Let us think of an observation that is similar to that seen as the outcome of the Hafele–Keating experiment. https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment Imagine you had two very very very very long trains, trains A and B, and that they are positioned closely side by side. Located at each window of each section of each train, is a clock. All the clocks have been synchronized. Those inside train A can look out a window and see clocks that are located in train B, and vice versa. Now imagine that one of the two trains, train A, rapidly accelerated up to a high velocity and then maintains that very same high velocity for a significant time period…

https://www.youtube.com/watch?v=tJ2AJJMcQXs I was watching this lecture by a MIT professor, and something didn’t seem quite right to me. Perhaps someone here can set me straight. If a light source and an observer are moving away from one another, the flash of light will be redshifted. If the light source is considered to be in motion and the observer is considered to be at rest, or if the observer is considered to be in motion and the light source is considered to be at rest, either way, the same redshift logically occurs. Conceptionally, it’s either drawn out as it leaves the light source or its drawn out as it’s being perceived. He then goes on to say tha…

i understand that the Gravity Field is static and not to be confused with Gravitational Waves which are dynamic. Gravitational waves are created when there is a change in mass-energy distribution and propagate at light speed (correct?). Do they have any effect on the static Gravity Field? Does the energy in these Gravitational waves get distributed throughout the Gravity Field it propagates through and so do these Gravitational waves get "converted" into a new Gravity Field?

In the thought experiments relativity says that my twin will age differently if he is traveling at eighty seven percent of the speed of light relative to me among other things. If, when he is moving at eighty seven percent of the speed of light, I can measure his vehicle, length,speed, etc. Then I assume he can measure things that pertain to me. My assumption is that he will view me as moving at eighty seven percent of the speed if light. His measurements might mirror my own. Is this asumtion right? Also let's say that before the vast difference in velocity we had agreed to communicate on a specific frequency, so that we can compare our measurements. W…