Relativity

Hi, I'm getting a bit giddy thinking about how to determine whether something has experienced an acceleration or not. eg. General Relativity has some examples.. how free falling in elevator is the same as floating in space, and standing in elevator same as rockets moving spaceship in space. But in all these examples couldn't you just say that the person never experienced any acceleration, that they were always perfectly stationary, and everything else just moved all funny. In fact couldn't you even stretch, twist and tie it to a yoyo, and yet it could still stay "hey, I never moved" everything else is just moving a bit crazy. If you treated an object a…

Hi. I read how to calculate time dilation (here's my version): I am stationary and I shine my torch up and find it takes 1 second to travel 300,000 kms. My co-star is moving to my "left" at speed v, and when they shine their torch up, I will find that it takes longer than 1 second to reach 300,000 kms. This is because light has to travel up 300,000 kms plus it also travels a bit to my left (vt). When I do the calculations I get the usual t' = t / sqrt(1 - v*v / c * c). But.. it doesn't work if we shine our torches sideways, ie. to my "left". When I do those calculations, I get t' = t / (1 - v / c). Anyone know why it only seems to work if we say light is travellin…

I wonder if this one interests anyone: When an object moves at a high speed, it contracts in the direction of motion right? Well, what if the object is actually a donut, spinning at a high velocity. How can each segment of the donut contract? Does this mean the donut would shrink, ie. radius reduces to zero.

I have a question about faster than light speed. For what i understood of relativity, it is impossible for anything to have a speed faster than light in a local frame, but the thing i dont understand is how does that make faster than light speed impossible globally ? I hope i posed the question clearly ? Mandrake

Einstein had a question when he was 14. That question was "When I fly (in vacuum and without gravity) towards in space with light speed (30km/s), then I take my mirror in front of me, will I see my mirror((in terms of physical words, his face emits light and strike the mirror and then back into his eye))?" After some periods of time, he got the answer, that is yes. Until now , I still don't know why it is possible. Relativity stated that nothing is faster than light, then what makes the lights from his face are fast enough to reach the mirror moving with light speed? I beg experts can help me solve it.

Does nature act on an other point of view or do you only experience it different from an other point of view. I assume nature never acts on a point of view and every point of view is different and all equally true. but if nature never acts on a point of view then how can the twin age be different at the end? There is no point of view to give them an equal age again. (twin age: about the twin paradox)

Can you say that nature doesn't make a difference between the two only that they orbit/accelerate each other. Because the decision which object is orbiting which object is based on a third reference (frame). (that is obvioulsy a free choice of the observer) Is it possible to say that object A orbits object B more than the other way around? (assuming a reference frame was choosen)

WHICH one of these is right 1) its not possible to travel at speed of light 2)its not possible to travel at or greater than speed of light if 1) is right. then does that mean theoretically u can travel greater than speed of light dont laugh at me pls. i am a mathematics student and i haven't done anything of relativity.

Thought you might like a little relief after discussing all the really complicated problems on this topic! If you looked at a realitivistic dice travelling really fast in some frame with it's '3 face' facing in the direction of motion (along the x axis say), what would it look like to a (distant) observer in the same frame who's looking up at the dice ( so looking at the underside or '6 face' ) as it shoots past (at right angles to) them. By 'see' I mean you take a photograph of the dice by having a photographic plate along the x axis that receives parallel light from the dice - this way you don't have to worry about a lens or crap like that. Think about the effe…

Everybody knows when one twin is traveling fast and comes back he/she will be younger that the one that stayed home. BUT something I don't understand: imagine an emty universe with only two twins each with their spaceship. Now the distance between the two is increasing with almost licht speed and after a while they found notting and come back and meet again. now the question: which of the two twins is older than the other ? if there is a planet hanging on one of the twins feed then they say its the one on the planet. what is it I'm missing ? Does that planet make so much difference ?

WHAT IF ???? What if science has gotten it all wrong ? What if science and the principles it is based on are all wrong ? What if there is another possibility that the science community has not grasped ? A collection of good questions, but how do we answer them ? Simple, I just tell you what I think, it will probably not make alot of sense because it comes from my mind and not yours, or it may make alot of sense because you think in a similar fashion to me. So here goes - The diagram used to explain Einstien's theory of relativity is a two-dimensional field with objects within the field creating a depression and therefore creating gravity, but I have a big problem …

Black holes (BH from hereon) are curious objects. The curious thing about them is that if you could watch something falling towards a BH you would never see it cross the event horizon (EH from hereon). For example, if I was watching a clock fall toward a BH, I would notice that it slows down more and more as it gets closer to the EH (it also would get dimmer and dimmer). This will always be the case from any view outside the EH no matter how long you wait. The clock will never be seen to cross the EH. It will slow down and then appear to be frozen (it won't be frozen but will be moving imperceptably). So does the clock ever actually cross the EH of a BH? I …

Hmmm... This is just a thought i had the other day, and there must be something wrong in my reasoning, but I can't seem to figure out why this wouldn't work: Say you had a HUGE train moving along the earth with a constant velocity of c/10 in reference to the earth. Inside this train you had a smaller train moving with a constant velocity of c/10 in reference to the larger train. Inside this you had yet another train (even smaller) moving at c/10 in reference to the small train. This train would then be moving at 3*c/10 in reference to the earth. Would it not then be possible to have 11 such trains in the same way as described above where the innermost train was…

Assume that I have a giant stick in space... | | | x | | | Now, lets assume I start spinning that stick clockwise around its axis in the middle. What happens when the outside edges of the stick start moving faster than light, but closer to the middle of the stick its still subliminal? Whats the effect on the geometry? [i tried to make beautiful stick diagrams out of text, but it didn't work ]

I read an article about SR, and after alot of re-reading, I still don't comprehend. My first question, it states that while moving at high speeds, time slows, but it doesn't say how or why, could someone please explain? Secondly, it states that when you view something in motion from a reference fram in rest, it becomes contracted in the direction of the motion, but again, it doesn't really say how or why. Finally, about the Twin Paradox. The article states that if two people, one standing on earth, the other flying away at 60% lightspeed, where the one flying away sends a message every hour, the one standing on earth receives a message every 2 hours. (I don't …

> The Ghost In The Machine Sayeth; > ------------------------------------------- > Of course it depends on the distance between masses. F=Gm1m2/r^2 Only if outside of atom, however inside of atom; .~ THE "NEW" UNIVERSAL LAWS OF FORCE 1) Newton...F=Gm1m2/r^2 for each particle inside atom. 2) Franklin...F=Gm^2/r^2 for each particle in atom. 3) Franklin...F=Gm^2/w^2 for each wave in and out of atom. 4) Franklin...F=Gm^2/rw for each particle wave in atom. Split particle of atom Key; m1=halfmass of same particle inside atom. m2=halfmass of same particle inside atom. .~ Newton's force equation; "For all people for a…

Say we have a spacestation and a rocket. The spacestation has a docking port, but at rest, the rocket is too long to fit into the docking port. However, at 90% the speed of light, the rocket will fit inside. When the rocket is traveiling at 90% speed of light the space station appears contracted (from the rocket's point of view), thus making even less room in the docking port for the rocket to fit. So, will the rocket fit?

We know the temperature and hence the frequency of radiation energy in the universe at quark confinement. The radiation from that moment of quark confinement is stretchd a million-millionfold. Its redshift is observed at 10^12. In other words, relative to our time, one million million of our seconds pass for one "universal second" to have passed. Is it possible that time on earth traveled faster than cosmic universe time? Say for us 15 billion years have passed, but on a cosmic scale, only a handful of days have passed?

If time realy stops at the speed of light then theres no time and if theres no time theres no space. So if theres no space and time evrything stops to exist. If what I said is true theres nothing that reches the speed of light not even light itself (sounds stupid, i know!) because then it would not exist?! we should then rename "speed of light" into "terminal velocity" or something like that (ahh, forget what i just said!)

Highly technical, but interesting. Post questions or comments. Alot of people like to argue about the theories based on this stuff, but hopefully this will elucidate how very unlikely it is they know what they're talking about Note: In PS format, get GSView here if you don't already have a program to read this filetype. general relativity.zip

Just wondering, i thought it was in a post somewhere but i cant find it :/ If you travelled at the speed of light for ten minute somewhere or over the speed of light, then came back, what would be the effect on time in earth? Does traveling at that speed do anything with time, like make it go back or forward ?

Lets say I make a conduit that is the length that light takes to travel in a minute. I then stuff it full of tennis balls so there are no gaps and all the balls are touching each other. I then push on the first ball. Instantaneously, the end ball falls out of the conduit. Is this not faster than light motion? I understand that each ball only moves the length of one ball, but all balls move together at the same time. Lets say someone is on the end of the conduit and waiting for you to perform the action. You shine a light towards the observer, but the ball would fall out before the light gets to their eye? I am sure this is not the first time you…

Is there a way to figure out the escape velocity of virtual particles? What causes them to surpass their escape velocity?why? What exactly are virtual particles? I started a thread on this same subject on another forum, but no one seemed to know what exactly virtual particles are. I learned that they were involved in quantum field theory, and they were mathematical solutions for something. :help: :feedback:

Is time quantized? In other words, is there a smallest unit of time that could not be divided into a smaller unit? Kind of like the atom used to be considered the most elementary fundemental particle, does time have a fundemental counterpart? Faf, any comments?

What do people like me do at 1:40AM? Read science articles of course! While browsing a collection of old physics articles Nature had a special on, I came across one of particular interest. http://www.nature.com/physics/lookingback/einstein/einstein.pdf Einstein himself explains how he came up with general relativity.