Special relativity and temporal distortion

[kenshi]

I've always found relativity to be fascinating. I've done some research on it, but there is one thing that puzzles me. I haven't found a thorough explanation about this. It is stated that a moving clock experiences time slower than a stationary clock. A clock moving near the speed of light would hardly experience time at all from a stationary observer. But since it's all relative, the opposite would be true. The stationary clock would appear to travel slow to the traveller. That's where the confusion comes in. The twin paradox states that if a twin went out in space at near light speeds and returned, he would be younger than his sibling. This sounds good from the perspective of the stationary twin. But for the moving twin, the stationary twin is actually the one that's moving, so his clock should be the one that slows down. So theoretically the twin that went out in space should return to find a younger sibling, not an older one. They can't both be older at the same time, especially when they're standing beside each other. So what is it that these relativity tutorials are leaving out?

[PhysBrain]

I think the main thing that is left out in such tutorials is that the twin at home is assumed to be an inertial observer. That is, his frame of reference does not ever undergo any accelleration. Whereas the traveling twin must be accellerated at the departure point, again at the turnaround point, and finally at the rendevouz point.

If my understanding of this is correct, it is the act of accellerating which alters the rate at which the traveling clock ticks by distorting its reference frame. This site has a nifty little Java applet and a decent description of the Twin Paradox: http://physics.syr.edu/courses/modules/LIGHTCONE/java/TwinParadox.html

If I get some time, I'll try to look into exactly how the non-inertial observers are treated within the context of special relativity.

[kenshi]

Interesting. I hadn't realized acceleration could play such a great part on time dilation. Java isn't working in my browser but the right frame of that page was still helpful. I tried to find a book on relativity at the library but the only general one was checked out.

[Franks]

I've a theary,
That times stops on a clock is because the clock moves so fast (speed of light) that the light that the clock reflects (so you can see it) is moving as fast as the clock (the light "sticks" on the clock), that's why you see the last reflection of the clock (when you are stationary and the clock moves toward you) But because the clock's has changed, but the picture isn't. If this clock would suddenly stop, you would see the clock as suddenly go "foward in time". But the fact is that the clock's reflection starts to "get loss" of the clock and reaches your eye. If you would film that and play it REAL slow, you would find the clock standing still, going slowly faster, and faster, and faster, and faster until it suddenly stops at the real time.
This means that both of your twins have grown equaly old, but you wouldn't SEE the twin going with the speed of light growing old.
It's just a theary.

FRANK

[jason]

i would like to add that as far as i know there was an experiment that was conducted using two atomic clocks (the most acurate clocks that exist) one left on Earth, the other on a space shuttle or some space vehicle. The clocks were aligned before the experiment took place. After the space vehicle returned, the clock that was in space was found to be slower than the clock that was left on earth. If this is true then it would appear that either acceleration and/or velocity has an impact on the, for lack of a better more exact term, "time constant" of the space vehicle and the clock inside of it. Time, therefore, would be relative but not nessesarily as based on the location of one of the observers but on what occurs to the time constant of a said object as it accelerates, regardless of who is observing. NOw if one twin goes into space and accelerates they will find an older twin on earth because the acceleration of the vehicle has changed the time constant of the moving twin causing time for the ship and the traveler to slow down, but only for them in that specific situation, it will not effect the twin left on earth because that twin did not go anywhere.

jason

[PhysBrain]

Although Franks is still thinking in terms of special relativity and inertial reference frames, his assessment is almost correct. I'm reminded of the line from the movie Young Einstien:

"Light travels to us from the hands on the clock to tell us the time. If we could travel away from the clock at the speed of light, then the hands on the clock would appear to have stopped. This moment would last forever."

At the time, that was the first explanation of relativity that I actually really understood. However that description is not totally accurate. One would not actually be able to see the clock anymore since it's light would have been red-shifted so far that it's energy would be too feeble to detect. In addition the observer would be essentially "running along side" the wave front of the light from the clock. Thus any two objects moving away from each other at or exceeding the speed of light are essentially invisable to each other.

If the clock were traveling towards the observer at the speed of light, their would be no way to know what the clock read until it passed the observer. Then, the entire time-history of the clock would arrive at the observer in the form of ultra-high frequency gamma rays nearly simultaneously. Again, not a physically realistic scenario.

But these situations are still well covered in the context of special relativity with only inertial reference frames. The thought experiment I'd be interested to hear about is the following:

Imagine twin A stays behind and lives his life in the 1G gravity well of Earth, while his brother twin B is placed on a rocket ship which is throttled up slowly so that as it leaves the Earth's orbit, the force on the occupants is also a continuous 1G. Due to the equivalence principle, both twins should age identically since a gravitational accelleration is indistinguishable from any other form of accelleration. I think it would be interesting to see how the two clocks would compare if it were possible to bring them back together again in the same reference frame by tailoring the rocket's trajectory so that it is always exerting a 1G force on twin B.

Just something to ponder when you have nothing better to do with your time.

[timeshifter]

i have nothing better to do in my time so i will post this..


einstein's theory of relativity works only up to the speed of light. it has no laws about once you reach the speed of light. in fact, einstein's laws say that faster-than-light travel is impossible.
but, if it is possible, does the theory of relativity is now worth nothing or worth even more?

to continue the theory, once you pass the speed of light, time would start going backwards in time.therefore, consider the following:


twin A stays on earth while twin B takes a high-speed spin around the solar system.
twin A would age at normal speed. twin B would grow older at a slower and slower rate until he hit the speed of light. then he would not grow at all.
now, suppose that twin B managed to go faster than light.
he would start growing younger at a faster rate the faster he is travelling.
does this not say that person B could go back in time far enough as to meet twin A before twin B left? i realize that this proposition is messed up a little, but i need to go and like now. any input would be more than welcome.

[irizarry]

In relativity faster than light velocities (grater than c) are allowed by particles with imaginary mass (tachyons). Also note that particle reactions in relativity are usually discussed either inside the light cone or on the surface of the light cone. Reactions outside the time cone are not ruled out. Also the time cone can be warped and twisted allowing for alternate particle interactions. All theoretically of coarse!

Irizarry
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[budcamp]

Is it not also true that space can expand at at a rate beyond the speed of light? That means objects within space can move apart at faster than the speed of light. They just can't move through space at faster than light.

Bud

[timeshifter]

my last statement was made before I had any knowledge of string theory. yes, it is possible that the universe is expanding faster than light. However, gravity would still have an effect on it. a person moving at faster-than-light speeds would sustain feelings that we currently have no knowledge about, due to our inability to travel that fast. So, to answer your question, it is all theoretical right now.

[Skatta]

I think there's a fairly simple way to explain time distortions based on everyone's common knowledge and it is in fact intuitive if you think about it. the reason it seems really alien to us is that ever since we were little time was explained to us as a constant. here's what i mean. i think everybody would agree that freezing a body freezes it in time, the body no longer ages. cold isn't a thing it's just a lack of heat and heat is just moving particles so a completely frozen body is a body in which all of its molecules relative to each other are stationnary. thinking in this way one would need to also assume that if all motion in the universe ceased (all large bodies all molecules everything) then so would all time, if you disagree already think about it, you can't make a clock, your brain is frozen your body is frozen nothing is moving anywhere in the universe. looking at it this way it seems natural that time and motion are correlated just by looking at that extreme because once one thing moves then there is time for that thing. however this way of thinking leads to conclude that "no motion=no time" and "some motion=some time" not that "more motion=more time" but it does make that third statement easier to swallow, to prove it is a little more complicated because you need first to prove that speed of light is constant and then use that to prove that third equality i mentionned. but here is a way to look at it to help you understand without technically proving it.

imagine for a moment that the number of steps a man takes represents his age if he walks 5 steps he ages a value of five (i would say five years but when time shifts years kinda loses its meaning and will end up just being too confusing). the number of steps represent how your body ages because of the relative speeds of the workings of your body. (like the rate at which cells die the speed the atoms in your body are moving relative to each other stuff like that.) now imagine that there are two men like this and they both take the same size steps so they both age at the same speed. now imagine there are two treadmills parallel to each other but one is slower than the other. these treadmills represent for example two spaceships one that moves really really fast and the other one that's pretty slow. it is also important to mention that in this analogy the total distance travelled by a man represents their location in time so if one man is behind the other then he is in the past and if they are standing next to each they are at the same point in time and so they can meet up and have a coffee or whatever. now imagine that both men climb on their respective treadmilll and start walking. since one treadmill is moving faster than the other one guy will be gaining more ground so will be moving through time faster. for the men to be standing together side by side the man on the slower treadmill would have to take many more steps than the other guy to get to the same point in time, or to have covered the same amount of ground. so this means that for them to meet at the same point in time the slower guy would have aged alot more. and so if they ever did decide to meet up for a coffee when they did meet it would have to be at the same point in time because they are meeting, and the slow treadmill guy would be alot older because he had some time to make up. if you were in a spaceship moving really fast the relative speed of all the molecules in your body would be the same as if you remained on earth just like the relative speeds of things inside a train aren't different when it is stationnary then when it is moving. so your body ages at the same rate whether the spaceship you're in is moving fast or slow but if your body is in a very fast spaceship that spaceship is moving through time faster and so carried you to a farther point in time than your natural aging would have brought you, and that's why if you leave earth and move really fast in a spaceship for a while when you come back everyone else aged much more than you.

[Skatta]

my last statement was made before I had any knowledge of string theory. yes, it is possible that the universe is expanding faster than light. However, gravity would still have an effect on it. a person moving at faster-than-light speeds would sustain feelings that we currently have no knowledge about, due to our inability to travel that fast. So, to answer your question, it is all theoretical right now.


i'm not certain exactly how much i would trust string theory and alot of contemporary quantum physics just because alot of it is derived from mathematics and sometimes only because giving something a certain value makes the math easier. and even if it weren't for that though i believe that mathematics are the only truth about the universe but they can be misinterpereted when they are explained in terms of reality for example if you look at a 4 dimensional object and graph it out so that it does from 3 to 4 dimensions what a topographical map does from 2 to 3 dimensions you get a bunch of 3 dimensional shapes this says nothing about reality and you could speculate many things to explain the 4th dimension based on that graph but it wouldn't tell you that the 4th dimension is time and that what you graphed was a moving 3 dimensional object freeze framed at different times just like a topographical map freeze frames heights. i am no quantum physicist so i don't know exactly how string theory was made but if i'm not mistaken it is based on some mathematical assumption i just forget which one. if you are looking for a description of really small things and of what atoms and whatnot are made of i guess go with that but i wouldn't use anything from string theory to disprove einstein because what you are most likely doing in that case is disproving string theory. Einstein was about much more than just the math. Stephen hawkings is much better at math but perhaps less good at philosophy. i'm not saying the universe can't expand faster than light because what is outside the universe is outside of space-time (but still i'm skeptical i would like to read more about that wherever you got it) but there's no way you're going to get a human being to move at lightspeed, even more so if the universe is expanding faster than or even equal to the speed of light cause you could never get out of the universe in that case.

[ad infinitum]

In response to Skatta - I would like to contribute my thoughts regarding time; and toss out some food for thought. Time(t) has more than one manifestation to consider.

The Physical (external) - Time(t), in our purest mechanical understanding should be considered 'the energy in the system', the system being the known Universe. Take away all motion; remove every observable characteristic of the passage of time, even the observer... and time continues to march on as long as matter or energy exist. From any coordinate plane, time exists as long as electrons keep orbiting nuclei, or energies keep radiating.

The Psychological (internal) - Additionally, time(t) also needs to be recognized and treated as the by-product of a self aware system; necessitated by our own consciousness for sequencing, perceiving and assimilating common events such as walking or watching a bird fly. Because it is REQUIRED for day to day living, it is so ubiquitous to our nature that we have to be extremely sensitive to which manifestation of time we are observing or discussing. This second quality of the passage of time only exists because the first one does, and it can get in the way of our understanding of the first manifestation.

These are two very different functions that need to be treated as unrelated. Unlike the first manifestation of time, our perception of the passage of time doesn’t actually exist as any more than an arbitrary point of reference created by our mind as a product of our nature for the purpose of survival.

It’s interesting to note at this point that we can even understand ‘omnipresence’ from this second manifestation as an infinite amount of time to get from point (a) to point (b).

Ok - fire away... don’t beat me up too bad here!

[bryce]

You can visualize time dialation using light clocks (http://www.phy.syr.edu/courses/modules/LIGHTCONE/LightClock/) (or, at least you can *try*!)

I learned recently that that old mantra (even my 9, 6 & 5 year old kids know this by heart!!!) "Nothing can travel faster than the speed of light!" isn't quite accurate....

Apparently, the c speed limit in special relativity (or is it general? Darnit I always get those two confused!) really the speed of light limit only applies to flat space (or space with a curvature so small as to be insignificant). When space is curved, the speed of light limit is only "local". (http://sciam.com/askexpert_question.cfm?articleID=000B02DD-3A2D-1C71-84A9809EC588EF21&catID=3&topicID=13)

Then there is the whole thing reveled by inflationary cosmology, about how space itself can stretch faster than light, so that you can have two galaxies on opposite sides of the universe traveling away from each other (realitive to each other) at the speed of light.

This has led physicist to speculate on how you could build an actual Alcubierre warp drive (http://en.wikipedia.org/wiki/Alcubierre_Warp_Drive) using micro warp bubbles (http://www.analogsf.com/0002/av0002.html)

It's not impossible, just hugely impractical.

But, a universe that would allow for FTL travel, would also allow for causality violation. You could send a FTL signal to a reciever somewhere out in space, and they could send a signal back to you (perhaps saying "Don't send us a signal!") that would arrive *before* you sent your first signal!

That all has something to do with the way Lorentz contractions skew light cones, and that whole "speed of light is a local limit" thing and "planes of simultaneity"...but don't ask my to explain it any better, I have been trying to visualize it all since I read "Singularity Sky (http://www.amazon.com/exec/obidos/tg/detail/-/0441011799/qid=1105600615/sr=8-1/ref=pd_csp_1/104-0399150-9472750?v=glance&s=books&n=507846) " and it just gives me a frackin' headache.

http://www.phy.syr.edu/courses/modules/LIGHTCONE/pics/mink-1.gif

There is a website that explains it here (http://www.theculture.org/rich/sharpblue/archives/000089.html) and another here (http://encyclopedia.thefreedictionary.com/speed%20of%20light)

And something about using FTL travel to travel in time here (http://www.zamandayolculuk.com/cetinbal/TimeTravelWarpDrive.htm)

And, of couse, physicist Ron Mallett's attempt to harness frame dragging (google it yourself, darnit!) to make time-like paths through space (you can also have space-like paths through time) to built a time machine (http://www.walterzeichner.com/thezfiles/timetravel.html)...

[Skatta]

just in response to ad infinitum, orbiting electrons and radiating energy is still motion. when ALL things stop time must stop, it is not simply the appearance of stopped time but time is in fact stopped, frozen bodies don't age, the relative movement of their parts have stopped though the planet and universe they are in still move, and so also through time and thus they can be revived at a later date. when all things, all atoms when all energy ceases to travel through space then time is no longer. Time is motion. when you think about it you can't have negative motion, there is stop and there are many speeds of go, there is no negative go, you can't be more stopped than stopped, there's no slower than stationnary, and same for time, time can go, fast or slow, or it can stop, it cannot go in reverse, though some will say that by warping the fabric of space time that you can go backwards in time because all of this speed of light stuff and whatnot is all relative to the fabric of space time (so essentially you could go faster than light becasue speed of light is relative to space so you can move space to get a treadmill effect). but i have yet to understand exactly how this could plausibly cause reverse time travel. But ya i know what you mean about how we arbitralily define time via our brain configuration. maybe we perceive time differently and some which seem to have good reflexes actually experience a sort of slow motion matrix effect because they are aware of more frames per second of time. Many other things are confused by our perception as well, like hot and cold and rough and smooth and colour and sound. I guess that's why it's taking us so many generations of intellectual development to get as far as we've gotten, as yoda says " you must unlearn what you have learned" but on the other hand without them we'd would not have progressed at all.... perception.... can't live with it can't live without it. :rolleyes:

[Kink]

Einstein came up in an age with no tv or radio. Entertainment was sitting around a parlor discussing ideas. To make people think, he came up with mind puzzles. The current mental scenarios are teasers, and have no realistic ways of scientific proof-how do you expect to see anything traveling that fast? But think, what the heck is red shift, but light traveling at a different speed from blue! Everybody is so scared to defy the Big E., but that's what he wanted, scientific discussion that would open new frontiers.

[timeshifter]

But, a universe that would allow for FTL travel, would also allow for causality violation. You could send a FTL signal to a reciever somewhere out in space, and they could send a signal back to you (perhaps saying "Don't send us a signal!") that would arrive *before* you sent your first signal!


I think that may be a little off... If you stop for a minute and think of c merely as a speed without noticable side effects, then the conversation simply happens very quickly. But, since we don't know what happens to time when the speed of light is exceeded, it's all up for speculation. However: if time slows down as velocity increases, then maybe it just stops when it hits c? And doesn't do anything beyond c? If that is the case, then faster-than-light anything becomes a worthless idea, as time will have stopped...

[timeshifter]

Einstein came up in an age with no tv or radio. Entertainment was sitting around a parlor discussing ideas. To make people think, he came up with mind puzzles. The current mental scenarios are teasers, and have no realistic ways of scientific proof-how do you expect to see anything traveling that fast? But think, what the heck is red shift, but light traveling at a different speed from blue! Everybody is so scared to defy the Big E., but that's what he wanted, scientific discussion that would open new frontiers.

"Red shift", in layman's terms, can be described as the object in question moving away from you, relative to your frame of existence. An object in a red shift is receding... R&R is how I remember it. But It also has to do with the frequency of the light emitted. If it's receding, then the wavelengths are farther apart, which is what shifts it into the red spectrum. Blue is just the opposite of red.

[Skatta]

I think that may be a little off... If you stop for a minute and think of c merely as a speed without noticable side effects, then the conversation simply happens very quickly. But, since we don't know what happens to time when the speed of light is exceeded, it's all up for speculation. However: if time slows down as velocity increases, then maybe it just stops when it hits c? And doesn't do anything beyond c? If that is the case, then faster-than-light anything becomes a worthless idea, as time will have stopped...

time does not slow down as you approach the speed of light. you merely become carried through time at a faster rate. In order for time for you, being carried , to be frozen you would need to be travelling infinitely fast so that in an instant you end up at the end of time or at a preselected point in time. this speed is not possible and neither is travelling faster than c. for you to be frozen in time, the relative speeds of all of the parts of your body must have speed zero, not unlike cryogenically freezing yourself, this way you don't age and can move through time at any rate, for you it's all an instant anyways.

[irizarry]

Time does not slow down for a person traveling at the speed of light. It “tics off” at the same rate for all inertial frames for individuals inside their respective inertial frames. Only the relative view between frames by individuals outside (observers) see different time lapses.

There is some non-relativisticl reasons time stays constant inside the individuals inertial frames:

(1) Our perception of where we are going in time (always progressing into the future) is defined by the second law of thermodynamics and the arrow of time (not just convention).


(2) We still have to operate with in the constraints of Planck time (Quantum Physics).


(3) Biologically we have a time established by our DNA. It says growing hair, digesting food, and oxygen exchange in the blood takes some reasonable amount of time. If these processes go to fast or to slow we are in big trouble. This third point is really based on the first two.

(4) Neurologically and Psychologically our brains can perceive time the way it does. There is limit to the speed at which the synapses can transfer information (some Information Theory in there). The limit is in milliseconds I think. Otherwise our senses just wont get it! So slowing down or speeding up time inside our reference frame as observed by ourselves would probably be detrimental. This point includes the previous three.

Imagine if time sped up so fast in our own inertial frame as viewed by ourselves that charge attraction out paced the ability of atoms and molecules to combine and separate. Matter would be out of whack and basically be a chaotic soup.

So one might say this is not testable. But it is! Suppose you passed a planet at the speed of light. To you the planet whipped by the window at the speed of light. On the planet some kid who stole his big sister’s telescope sees you whip by at the speed of light. Is something like this going on for us. Yes. Each instant in time subatomic particles whip by us at speed “c”. Yet we do not turn into mush! Why? Because time in our inertial frame has not changed.

Next issue: Faster than light travel.

Other than relativity is there some other physical theory that suggests this is possible?
Actually there is. Einstein attempted to include it into both relativities but failed. So what is it? Mach’s Principle. It implies faster than light speeds. There are some dimensional theories like parallel universe theories that suggest time is no big deal anyway.

Irizarry

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[Skatta]

Is mach's principle the one where they think faster than light travel is possible by moving the fabric of space and then moving through that, and thus be travelling faster than light?

[irizarry]

To answer Skatta.....

I think its similar to what you mention except velocity is illusionary in this case. There is no technology to exploit this just many very interesting papers.

In fact Einstein tried to incorporate the principle into relativity but failed to do so. This was just recently (with in the last 7 or so years) sucessfully incorporated into relativity.

Right now I'm still trying to understand the principle myself. Some theories require a leap of faith to jump a hurdle so that one can contemplate the whole theory. Quantum is like that. My leaps of faith are little low on inventory but this is more of a personal problem. If I'm going to press on I'm going to have to evolve or I'll continue to be stuck in the theory were I am now.

Irizarry

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[PhysBrain]

There's nothing too complicated about Mach's principle. Although a little background may be in order to properly understand what it means.

Since Galileo and Newton first began codifying the laws of motion, it was always assumed that there was some fundamental reference frame or absolute space in which all matter moved. In the mid-1800's, Maxwell unified electricity and magnetism and discovered electromagnetic waves. This prompted scientists to begin searching for the etherial medium through which the waves were propagating. For many, the reference frame in which this ether was at rest could be naturally interpreted as Newton's absolute space. By 1887, Michaelson and Morely had shown fairly conclusively that there was no ether wind to be measured. So, what did this mean for the absolute space? If there was no ether, then what else could we possibly use to define a fixed reference frame from which to measure all motion?

In 1893, Mach first put forth his idea that the only reference frame which made any sense was that which was defined by the "fixed stars". That is pick any star and you've determined a preferred direction in space. Pick any two stars, and you've established a preferred orientation. I don't think he ever really developed this notion into a rigorous physical theory, but as has been mentioned, it did have some influence on Einstein when he began formulating his theory of relativity. In my mind, I put Mach's principle on the same shelf as Schroedinger's cat. It's more of a Gedankenexperiment.

What is most notable about Mach's principle is that it was the first time someone attempted to link the inertia of a body to that of very distant matter. In effect, it was the first time that someone thought that the way we percieve our reality is in fact dependent on the overall distribution of matter in the universe rather than on the fundamental essence of space itself as everyone before him had. Space and the matter residing within it were somehow linked together. This has huge implications, many of which were eventually realized by Einstein.

[Adrian]

Reflecting back on some things that were mentioned regarding the various comments that have been made about time variances due to acceleration of matter. There have been a number of comments made suggesting things such that the "apparent" slowing of time, or time dilation, as velocity increased, was relative to the point of the observer versus the traveler. According to Einstein's twin paradox theory, the actual slowing of time wasn't truely perceived by the traveler, instead, the traveler experienced normal passage of time. The trip, to the traveler was all of an hour, but upon returning, his twin brother was an old man. This suggests that time's movement is absolutely relative to both the observer & the traveler. If you think about it, the traveler would never know of his twin brother's advanced aging, while that aging twin, would think his twin was never going to return. Interestingly, time was very much moving as normal to each party. This now suggests that the very fabric of time & space itself is what is actually changing relative to traveler.

Take, for instance, traveling to a distant star, whose distance is 1 light year away. This would be how much time would pass for the person observing the ship as it made it's way to it's destination, but to the traveler, the trip would be instantaneous. According to Einstein, this would be due to the fact that as matter aproaches the speed of light, time continues to slow, proportional to the velocity, but not to the traveler. Again, the trip would be instantaneous to the traveler.

This actually makes perfect sense to me. What doesn't make any sense according to Einstein's theory is that he caps velocity as terminal at the speed of light, but I can't help thinking that that limit is more a result of mathmatics having viced any further probabilities that would extend beyond the speed of light. I can't help but feel that this velocity limit was the result of his energy conversion formulations, but I tend to challenge that energy and matter are far too removed from each other for there to be such a limit...I just think that because matter is "bound" by energy, it's composition can be potentially compressed, possibly through acceleration, but the idea that matter would totally convert to pure energy as it approaches the speed of light seems a bit more like one of a very large number of mathmatical products rather than the somewhat finite and seemingly conclusive predictions that only one man's calculations could produce. I have the feeling that Einstein was a bit less broad and more focused on a series of topical analogies than the all too evidently endless variables that the universe actually introduces into the extreme myriad of possibilities.

[Skatta]

but the idea that matter would totally convert to pure energy as it approaches the speed of light seems a bit more like one of a very large number of mathmatical products rather than the somewhat finite and seemingly conclusive predictions that only one man's calculations could produce.

I think the whole deal is that matter IS energy. This greek dude i think, a philosopher from back around aristotle's time called Parmenides i feel discovered this before einstein did with a simple argument that goes something like this if i remember: What is is. What is not is not. there is no in between state. therefore, change is an illusion and the universe is a solid block. This seems so wrong at first but it makes sense. it is saying that you cannot make something from nothing. things can either exist or not exist but you can't make something exist from a non exist state. because nothing is nothing. so everything that exists must be the same thing but in different forms.. the fact they seem different is an illusion. This to me seems like a perfect argument even though it was discredited by the atomists (wrongly so in my opinion) and seemingly forgotten forever because Parmenides isn't a household name and i think should be. If you think about it everything is energy. he was right. the universe is a solid block of energy. all mater is energy and that's what e=mc^2 means. it quantifies how much energy a unit of mass is. that's why atomic bombs are so crazy because they are transforming mass into explosive energy, both are energy in different forms. all "things" in the universe are merely different manifestations of the same thing, energy.

so, then, my question is... if you have a mass... and a contained equivalent measure of energy... would they both equally bend the fabric of space? I would think they must. and if they do then mass being the source of gravitationnal influence must be imprecise and it is instead the effect of energy, it simply seems to be mass because mass is such a highly concentrated and localized source of energy. I know gravity affects light and light has no mass,, that's why it moves so fast.

[solar_system]

The solar system is not flat shape, it is a spring shape, why do you think the space is flat?

[time&space]

I think to tell who is older you should decide who are u staying with or how hast are u traveling first,that makes your time different from others!
for example,if twin A is traveling at near light speeds.and u are staying with tiwn B.then you can see twin A is younger.because his time moves slower in your time coordinatel. And if you are relativily quiescence with twin A,twin B is younger. everyone has their own clock,or time coordinates!!!
you needn't worry about diffenent clocks.becaus to each one,every thing is moving equally faster or slower compared to another one.thus all the rules are the same to anyone and the universe appears the same to anyone.you will never tell the difference because you just have one&independent clock.
universe is universe but it appears different to different people .

CONTACT ME AT space_time_sp@yahoo.com.cn:)

[time&space]

I think to tell who is older you should decide who are u staying with or how hast are u traveling first,that makes your time different from others!
for example,if twin A is traveling at near light speeds.and u are staying with tiwn B.then you can see twin A is younger.because his time moves slower in your time coordinatel. And if you are relativily quiescence with twin A,twin B is younger. everyone has their own clock,or time coordinates!!!
you needn't worry about diffenent clocks.becaus to each one,every thing is moving equally faster or slower compared to another one.thus all the rules are the same to anyone and the universe appears the same to anyone.you will never tell the difference because you just have one&independent clock.
universe is universe but it appears different to different people

contact me at space_time_sp@yahoo.com.cn

[tempest97]

I contribute this 2-page treatment of the twin paradox. (http://www.sysmatrix.net/~kavs/kjs/addend4.html)

[Skatta]

The solar system is not flat shape, it is a spring shape, why do you think the space is flat?
I don't know if this is in response to my post... but i don't think the universe is flat. so far, i am conviced it is in 4 dimensions though string theory suggests more. and so i can't think of the name that "shape" would be or rather i think the universe isn't a shape at all since shapes are 3 or less dimensional things. why do you think the universe is a spring shape?

[aristagon]

this isn't really helpfull as far as answering anyone's questions but I thought it would be interesting to discuss.

Skatta was mentioning that the arresting of an objects motion would stop time and/or aging and I'm inclined to agree. Since we all agree that motion is energy, wouldn't our quickest course to acheiving efficient space travel lie in somehow sucking this "energy of time" out of the ship and crew to be used as a means of propulsion - motion begets friction, friction begets heat, heat begets(it's like the bible!) a very common form of propulsion that we use today. Thus the trip would be instantaneous for the travellers and the vessel would not have aged, something no one else has touched upon when discussing the validation of the twin paradox theory. Just plain croygenics would leave travellers to awake in a decrepid, corroded ship in which systems like life support might have already failed.

Anyway, even if the ship took a long time to arrive at it's destination(based on the observer's perspective), time would not have passed for the ship or crew. Wouldn't this be a 99cent store version of the desired effects of travel at light speed?

[timeshifter]

How do you figure the ship would be corroded? It's space... there's nothing to oxidize the ship. And as for life support, ever heard of the idea of shutting it down until the planned time of arrival and bringing it online in time for the crew to wake up, thus saving most of the energy the ship had to begin with?

[aristagon]

I hadn't quite thought it through when I posted this comment. I was probably thinking about the interior of the ship needing to have atmosphere conditions similar to Earth and therefore having the ability to corrode just like everything does on this planet(except Twinkies and McDonalds styrofoam). I'll just insert my foot in my mouth.

However, unless cryosleep is perfected or we use something like what I suggested, life support would need to stay on in at least part of the ship or all you have is an intersteller exploring coffin seeking out new life and new civilizations...blah, blah. Anyway, I'm just saying that society still buys cars that don't last longer than 20,000 miles(like Kia's), so good luck on having any system run continuously for that long of a trip with any technology from the near future.

[iseason]

i would like to add that as far as i know there was an experiment that was conducted using two atomic clocks (the most acurate clocks that exist) one left on Earth, the other on a space shuttle or some space vehicle. The clocks were aligned before the experiment took place. After the space vehicle returned, the clock that was in space was found to be slower than the clock that was left on earth. If this is true then it would appear that either acceleration and/or velocity has an impact on the, for lack of a better more exact term, "time constant" of the space vehicle and the clock inside of it. Time, therefore, would be relative but not nessesarily as based on the location of one of the observers but on what occurs to the time constant of a said object as it accelerates, regardless of who is observing. NOw if one twin goes into space and accelerates they will find an older twin on earth because the acceleration of the vehicle has changed the time constant of the moving twin causing time for the ship and the traveler to slow down, but only for them in that specific situation, it will not effect the twin left on earth because that twin did not go anywhere.

jason

something that could be missing is the true relationship between time and space....
wouldn't the distance the object covered regardless of the speed create specific parameters...
for instance at atomic trillionths of a second is commonplace.....but the distances covered are tiny......in space or light speed the distances are vast....
if i travel at light speed but only create a small orbit.....or circle....... there is going to be a greater disruption of the environment than if i went from one side of a galaxy to another.
also the amount of time and therefore distance covered is directly relative to the "twin " left behind....if he follows at a slower speed , does he eat into my time...
or if he moves the other way , does he add to "my" light speed , since the whole experiment is based around my time verses his time.

if i am travelling at light speed i will necessarily be blind since the eyes i see with used light which has a constant speed . otherwise , i have a faster than light theory in the making.
if i look behind the same is true since no light could catch up with me... there is no chance of me seeing anything at all since the light must go faster than i in order to overtake me..
looking sideways the image could only survive within the band of a single photon since any deviation past this puts it thicker than light and slightly ahead or behind. travelling at equal speeds is an invalid arguement since a deviation thicker than one photon makes the travelling time to my eyes much too long to be credible. either way , i am seeing faster than light or light must catch up with me....

so in light travel ....i am blind....

cheers
iseason

[aristagon]

In response to iseason-

If you're moving on a train at speed and throw a ball forward, you add the ball's speed to the train's. So what if you had a light source inside of your ship, wouldn't that light be emitted at a speed where you might be able to see it still?

[timeshifter]

Nope. Do a bit of research... Light is supposedly a constant in all reference frames. Therefore, a light source inside of a ship moving at the speed of light still only moves at the speed of light.

[PhysBrain]

There seems to be some misconceptions floating about in this thread regarding the relativity of space and time. The most obvious is the "freezing stuff will make it age slower". I'll comment on this one now, and others later as I have time to go back and reread the thread.

Temperature is a measure of the average random kinetic energy of a collection of atoms and molecules. The more random movement, the higher the temperature. Theoretically if you could lower a body's temperature to absolute zero, then all of the atoms and molecules of the body would be locked together with no random motions allowed. Quantum mechanics actually forbids this state from occurring due to the Heisenburg uncertainty principle (because then we would know the exact positions and momentums of all of the particles which is not allowed). So, freezing something in the sense that you cool it as far as possible towards absolute zero would take away nearly all of the particles' translational motion.

While in the chemical and biological sense, cooling of a system usually results in a substantial slowing of the rate at which the chemical and biological processes occur, in a relativistic sense the opposite effect is occuring. In relativity, the faster an object translates through space (i.e. moves from point A to point B), the slower it's internal clock is observed to advance from the reference frame where points A and B are stationary. In other words, faster objects appear to "age" at a slower rate than stationary or slow moving objects. The rate at which time progresses for an object at rest in a particular reference frame is referred to as the proper time for that frame. So, as the temperature of an object is reduced, the translational velocity of it's constituent particles is also reduced. As the particles get closer to being at rest in that reference frame, the rate at which their internal clocks are progressing actually begins to approach the proper time for that reference frame.

So, from a relativistic perspective, cooling an object will actually make it "age" faster in the reference frame in which the object appears to be stationary.

[Skatta]

So, then what you are saying is due to Heisenberg uncertainty principle that time must exist. since there must be motion of all particles in the universe, since having them stopped would mean to know both their location and momemtum. I'm not sure how heisenberg figured this out but.. if these are particles and they are moving then wouldn't it or couldn't it plausibly be possible to slow them down somehow? I think that freezing a body doesn't quite achieve the proper effect meaning to completely relativistically pause the body in time, but really,, relativistically or anything else should be the same. it's just the way the universe works. it's just that relativistic ways of working were hard to figure out, and came about from thinking about light. it is clear that if you freeze a body it ceases to age relative to itself, though it still exists in a time frame that is moving and so stuff can happen to it and should it be unfrozen it would end up in another time frame. it is also clear that should it be possible, and i think that if time had a beginning and will have end it must be, to stop the relative motion of all particles and everything in the universe time for the universe would need to stop. should nothing move there cannot be time. If there is time something must be moving. perhaps the only way to achieve this is with a big crunch.. but i can't see how time of the universe could have ceased without the momemtum of all particles relative to one another be zero and to simultaneously be able to know their location... that is if there was "time enough" so that we could walk around, think, and observe and somehow record their position and momemtum... except since all of our particles and everything would be just as stopped we would essentially have ceased to exist.. at least in the 4th dimension. Maybe heisenberg's principle can only be applied to 4 dimensional particles or something... do you know why the principle is that way? it seems to like it must have something to do with the sheer speed of the particles. they've never managed to slow a particle enough to know both the location and momemtum? i have a feeling that the explanation for the principle would be mathematical. is there another one?

[PhysBrain]

That's an interesting perspective on Heisenburg's uncertainty principle. I'm not sure if there is a causal relationship between the observations of perceived time and uncertainty in the measuring of position and momentum. I do remember reading once that space and time are created by the presence of matter.

Let's see if I remember correctly (I think this was in one of Brian Greene's books, probably The Fabric of the Cosmos). According to equations of general relativity, a single particle, alone in the universe, creates a tenuous space-time in it's vicinity. You can kind of think of it as a problem of measurement. How do you judge distances or durations when there is nothing else in the universe to measure with or against. Even something as simple as exchanging photons between two charged particles is not possible.

The more particles which are present, the more substantial space-time becomes. Individual particles may have no sense of time, but a group of particles exchanging photons back and forth will begin to develop the capacity to mark both distances and durations. Eventually, you get enough particles flying about to form atoms, then stars, then planets, then people whose photon and and particle exchanges are complex enough to not only directly experience space and time, but also to ponder the nature of its existence.

So, if space and time are ultimately percieved by the exchange of photons between charged particles, then one can begin to see the significance of relativity theory. If everything from particle motion to chemical reactions are governed by the interaction of electromagnetic waves and charged particles, then the specific interactions of the waves with particles in different states of motion becomes very important. Einstein developed special relativity by trying to reconsile how light would be obervered in different reference frames.

[Skatta]

do you mean that the exchange of photons are like a clock? a clock based on light speed? that's interesting because this clock would be the same no matter what speed it is moving at. like some sort of universal time... I think i understand what you mean by tenuous time. I think of time as the displacement of an object. the faster it moves the faster it passes through time. if it doesn't move, there is no time. but movement must occur in relation to something else. so i guess you need two units of energy minimum which move in relation to each other in order to have time. (unless there is some sort of ether or something acting like a stable point like a graph) but i would think any kind of motion whatsover would be sufficient to create time even the rotation of an object relative another. or actually.. if an "object" can be shaped like a wave it could exist in time by moving relative to itself i think, so maybe the most elemental of things which could form matter,. or energy itself in some raw form, would be a waveable thing.

I believe that rather than space and time being created by the presence of matter i think of it more like presence of 4d energy, and so that would include matter and everything else in the universe. i think i posted a thing once about parmenides and a pretty simple but inescapable argument of his. in it he basically said that the universe is all just one same "material". he got later rejected for it in his time because people couldn't fathom how stuff could move around without the existence of empty space. however, they thought probably that air was empty space when in fact there is gas, and empty space doesn't really exist. there is always something, light, gravity well, neutrinos, atoms all over the place. I can't think of a place void of energy. there is no nothing, the universe is one solid made of the same substance. and now much later einstein came along and called this substance energy, and said that matter consists of mc^2 amounts of this energy.