Relativity

I finally figured out why faster-than-light speed travel isn't possible. Go me.

Is it possible that the speed of light (in vacuum) is 0.999999999c (or some other number of 9's after zero) rather than 1c? Here I define "c" as the universal "speed limit", and obviously not as the speed of light itself. I know that it would have to be so close to c that we would (at least currently) be unable to measure any difference. But by my understanding, something accelerating very close to c (relative to us) would eventually move fast enought that it would seem to move at c from all reference frames, as far as we would be able to measure it.

The proof of the absolute zero velocity inertial frame is focused on the simple statement that the inertial frame should be proved invariant in absolute space and time for some delta t > 0. This proof is not subject to agreement by any number of scientific thinkers as the proof is transcendent to the mental dynamic of the signifcance of any "acceptance" protocol. The use of two widely understood postulates of light iare incorporated in the proof First is the postulate that the motion of light is independent of any motion of the soutrce of the light and second, the speed of light is a constant c measured form any inertal frame of reference,and included in t…

The EEP assumes the complete physical equivalence of a gravitational field and a corresponding acceleration of the reference system. I know this principle is supported by many experiments. But recently i read an unknown article which seems to contradict the equivalence principle. I don't know how seriously to take it. You can read the entire book here.

So it seems to me that relativity of simultaneity in GR really speaks to the irrelevance of actual simultaneity as opposed to a true sense of events occuring simultaneously as the causal structure of reality, at least within GR models, is bounded by the speed of light. But the immeasurability of simultaneity aside, haven't things like quantum entanglement and the Aspect experiment shown us that through non-locality things can be causally linked which aren't bound by the speed of light? Wouldn't that paint a picture of a universal 'now' in which events are truly simultaneous throughout all frames of reference, and that the apparent effect of relative simultaneity is m…

I'm trying to weave my way through General Relativity, but I find difficult to learn the concept of Christoffel symbols of the second kind. They are defined as [tex] \Gamma^l_{ki} = \frac{1}{2} g^{lj} (\partial_k g_{ij} + \partial_i g_{jk} - \partial_j g_{ki}) [/tex] However I really don't know how to do the partial derivative of the metric tensor; I do know how to do partial derivarives of 0-rank tensor fields and 1-rank tensor fields, but I'd be very happy if someone could explain me how to do partial derivatives of 2-rank tensor fields. A link to a page explaining how to do this kind of derivative would also be welcome Edit:It seems that latex is down,…

This came up in post 12 of this thread, and rather than having the topic there branch, I thought i just might move my question to another post. Here is what arose in the other thread: Here is what i would ask you about. You say that if special relativity holds then you are not in an accelerating frame. Here is my question. Could you run through an explanation of the time dilation formula of SR for me. Specifically, I want to see how you explain each of the letters in the formula, be they constants, or variables. I suppose I am most focused on v. Dt` = Dt (1-v^2/c^2)^(-1/2)

Thought experiment: You stare at a clock, and nothing else is moving, nothing changing, no internal clocks either (or imagine all you have is your internal clock). The clock ticks once, and then again but the second time a longer amount of time passes before it ticks. Would you have any way to tell that the second tick took longer before it happened? How could you? Whats the point? The subconsious definition of time is something like the difference between events. The smallest possible unit of time is the smallest amount of time in between two events. The smallest possible unit of time recognizable by a human depends on the physical nature of the mind (refres…

Johnny brought up a point about synchronizing clocks in relativity. There is a difference between synchronization and syntonization. The former means that the clocks read the same, the latter means they have the same frequency but no effort has necessarily been made to make them read the same. You can do one without doing the other. There is also possibly an issue about how one does the synchronization of a clock. To be a valid application of special relativity you have to use relativity principles, and know when they apply.

hello if im going at a reltavistic speed, .9c, and im travelling towards point A, does pt A become a shorter distance for me due to length contraction. i see that it cant because the distance isnt moving, but im unsure about what this person would see outside. .e.g length contraction of pt A which lets say is a sun. if the sun would contract doesnt this make the distance even longer. thanks

1- Is an object in geostationary orbit, pointing in a steady direction toward the Earth (not rotating) considered to be at rest WRT the Earth? 2- If X and Y are at rest WRT eachother, and Z and Y are at rest WRT eachother, then Z and X must be at rest WRT eachother. True or False? Thanks.

Ok, I can't keep this straight in my mind. When an object accelerates close to c, does its gravity increase, or is it just inertial mass that increases? I dont think that gravity increases, but I want to make sure on this. (you can explain your answer if you feel like it, but really just saying which is correct would be fine)

in the sense of mv, it would be. in qm would it be? i think it would, because the difference in time would make a period longer/shorter which would change the wavelength thereby changing the momentum. in your frame of reference, do you have momentum? in classical physics, i would say no, but in qm, i would say yes. if momentum is relative, does that make energy relative? wait, thats a stupid question: m=m/(1-(v^2)/(c^2)).

I'm curious, what math and physics materials are you working through?

how do you deal with an object that has imaginary energy (a particle moving faster than light) in the theoretical context of course

Einstein said we are all traveling through the time dimension at C....can we feasibly say that one second equals to around 3 times [math]10^8[/math]?

What is the maximum theoretical rate, (speed), of time relative ours here on Earth ? If motion through space and gravity changes the rate of Time and both velocity and gravity has limits, thus should also Time rate have an upper limit.

I love the word and all it pertains to. But does the word relavitist have anything to do with relativity? I keep hearing it. I agree with the word tho need more information about the meaning. Paul/pljames

There is a theory in physics stating that all possible outcomes that do not happen do happen. Except in an ifinite number of parallel universes. Based on this assumption, one can arguably say that every time me make a choice with two possible out comes, we create two new universes. In example, say (you) decide to make a sandwich. However, you are perplexed as to what you want to make...(don't worry, this happens to me often too... ) Finally, you are able to narrow it down to two possible choices of food. A peanut butter and jelly sandwich, or ham on rye. In htis universe, lets say you picked ham on rye. However, at the very moment that you decided to make ham on r…

When you are in freefall or in orbit around a planet, you no longer feel gravity... you become weightless. Do you still experience time dilation at the same rate as you would if you could feel gravity. For clarity.... John is standing on a platform on the moon. Jane is orbiting the moon at the same height as the platform that John is standing on. Does time pass at the same rate for both Jane and John? Damn... I can see I'm going to get into some trouble with the fact that Jane and John are moving WRT one another... hopefully you know what it is I am asking.

OK, I have a question here. If getting close to the speed of light distorts how time is percieved(slows time down), then what about not moving at all, compaired to how we perceive time. We are moving. Exactly how fast can be up for debate. Studies have shown the milky way is moving at 370 miles per second(Relative to other galaxies). The solar system, is also moving within that system, and the earth is moving there within. I see that it could be also possible that all of the galaxies we know of are moving at a rate, relative to something else we are not aware of, and therefore cannot calculate that speed. So my question is, ... if we are moving so fast, how wo…

The figure shows a simple linear "Sagnac" arrangement where photons emitted from the moving (moving to the right with velocity v wrt the emission point of the photons) M midpoint of L and R clock/mirrors directed at the L and R clocks. Clearly, the photons arrive at the clocks sequentially. What is not so obvious perhaps is that the lp and rp photons arrive at the moved midpoint simultaneously. The dashed lines show the movement of the frame in increments of 'vt', the time it takes the lp to arrive at L and reflect back to the original emission point. The delta symbol is the distance the frame moves when the photons move to the L and R clocks when located a distance 2vt f…

Is the existence of the graviton particle really neccessary? If gravity is merely a side-effect of mass in the space/time universe, why is it regarded as a 'force' such as electromagnetic, weak and strong? I don't believe it requires a specific entity to transmit this force, as gravitational influence is just an inherent property of the universe, caused by the pressure of matter in space/time. Oh wait... darn it. *ahem* If pressure causes friction, gravitons could be what are generated by that 'friction'. I was all convinced, then I had to go and re-confuse myself by writing it down using pressure as an analogy.

Can somebody tell me where I went wrong? Here's the scenario.... I'm standing outside looking up into the night sky. Unbeknownst to me there is a spacecraft travelling towards me at 90% c. Ten light seconds from Earth's frame of reference the pilot turns on the headlights. I will eventually see the headlights, determine them to be 10 light seconds away. After I first see the lights come on shouldn't I see the spaceship go by 1 second later? Will this create an illusion that the spacecraft is travelling faster than c? Will my eyes be absorbing photons at a higher than normal rate? Ok guys and gals...where am I going wrong? I dreamed of this one night after thinking abo…