Explain the Theory Of Relativity

[Markxxx]

I know something about it, but is there a more or less simplified explination somewhere on the "net" I could read. Or someone explain it here. I know you can't really "simply" explain something that complex but can someone help?

[EnigmaOne]

AltaVista: Simple Query "The Theory of Relativity" (http://www.altavista.com/cgi-bin/query?pg=q&kl=XX&stype=stext&q=The+Theory+of+Relativity&search.x=40&search.y=5)

That should get you started.

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--Kalél
(The Original EnigmaOne)
Common ¢ for all ages.

[jayron 32]

OK, here's the shortest I can explain a part of the theory of relativity:

Item 1: Speed of light

1) Light moves at an absolute velocity. The velocity of light in a vacuum is a constant.

2) Speed=distance divided by time, or v=d/t.

3) In a function like v=d/t, variables behave in a similar manner (a strange way of putting it, but trying to stay non-mathematical). Thus, if v has a maximum limit, then as v approaches that limit, d must become infinitely large, and t infinitely small to compensate.

4) Thus, when it comes to traveling in the universe, since at some point velocity becomes constant, the rate at which time passes as you approach that maximum speed becomes smaller and the distance between where you are and where you are going becomes smaller.

Item 2: Non-identifiabilty of moving source

1) There is no way to tell, when two objects move past one another, which is moving and which is standing still.

2) Look at item 1, #4 again. As you approach the velocity of light, your time speeds up and distances become smaller, so light always appears to be moving the same speed regardless of what your absolute velocity is.

3) Since the only constant velocity is that of light, and no matter what speed you are moving "light speed" is always the same for you, you have no way of telling if you are really moving, or if everything else is moving instead.

4) Thus all motion is relative and there can be no defined absolute motion.

Item #3) "Infinte" speed of energy

1) Pure energy, in a "frictionless" environment, travels at maximum speed, the speed of light.

2) Think of a line of soldiers marching. If the all take a step with their right foot at the same instant, the whole line can move forward at once, with the back person moving at the same time as the front one. This is an "ideal" situation.

3) Energy is the same way. Imagine a pulse of energy like the soldier at the front of the line. As soon as he starts his step, everyone else is starting their step, and so there is no time difference between when the first soldier steps and the last soldier steps. The time it took this "energy" to travel down the line was zero (since the whole line moved at once) so the velocity was infinite (or light speed, the maximum velocity).

4) Now, imagine your average untrained people in a line. The first person takes a step. The second person realizes that they have taken a step, and themselves take a step, and so on down the line. This is a "real" situation.

5) Eneregy that has to travel through matter is like this too. Since not everyone steps at once, it takes time for everyone to move forward a step. The last guy moves forward some time after the first guy finished his step. This is what happens to energy when it has to travel through matter. Thus, light, "pure energy" travels at its maximum in a vacuum. If there's any matter in the way, it behaves like the second line of people, and it takes time for light to travel from point a to point b, and so light in a non-vacuum travels slower than the speed of light.

Item 4) E=mc^2

1) The calculus for this is really astronomical, so please forgive me.

2) See point #1. This is not what really complete, but it may help you keep this straight, and it's almost close to the truth.

3) Since energy could move along at the speed of light if it wasn't for matter getting in the way, we can look at matter as a sort of "slowed down" energy; if we could travel at the speed of light we wouldn't be getting in the way of the rest of the energy, we'd actually "be" that energy. So really, matter is energy, and energy is matter. Energy is merely the "limiting case" of matter, or if you prefer, matter is merely the "general case" of what energy is. They're the same thing, just behaving in a different way.

4) We need a mathematical way to relate these things. Since matter and energy are the same thing, there should be a direct, linear relationship between the mass of something (how much stuff is there) and its energy if it were traveling the speed of light (since at that point it would be pure energy). A linear relationship is always in the form y=ax+b, where a and b are constant. Let Energy(E)=y and mass(m)=x. E=am+b. Since at zero mass, there is no possible energy, (plug zero into the above equation for both m and E) then b must also equal 0. So now we've got E=am, or energy is equivalent to mass times some constant. Einstein, in an elaborate proof that is quite above even my head, showed that indeed, a=the velocity of light squared. We use "c" to represent the velocity of light. So E=mc^2.

All of this is a part of Einstein's theory of "special relativity" Just as he tackled the speed of light in "special relativity" he tackles gravity and a whole other bunch of stuff in "special" relativity, when he proved, among other things, that it is impossible to determine whether the source of an acceleration is due to gravity or thrust (i.e. if something is falling or is being pushed or pulled).

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Jason R Remy

"One pill makes you taller, and one pill makes you small, but the ones that mother gives you don't do anything at all"
-- Jefferson Airplane White Rabbit (Slick, G. 1966)

[jayron 32]

Oops, the gravity and thrust stuff is in, as I should have said, the theory of "general relativity" which extends special relativity to accelerating objects as well as constantly moving ones. Remember: constant speed = special relativity. All motion, including acceleration = general relativity.

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Jason R Remy

"One pill makes you taller, and one pill makes you small, but the ones that mother gives you don't do anything at all"
-- Jefferson Airplane White Rabbit (Slick, G. 1966)

[GOD]

Relatively simple stuff.

[Nickrz]

Easy for you to say.

[Czarcasm]

Alternate Theory of Relativity:
If your parents didn't have any children, there's a good chance you won't either.

[handy]

It's only a *theory*

In other words, not a law.

In other words, always trying to be dis-proven.

Whew. No use trying to memorize theories, shoot, I have enuff to do with just the truth.

The TRUTH? You can't HANDLE the truth!

[jayron 32]

Urgh, once again educating the minds of people who refuse to listen...

It's only a *theory*

In other words, not a law.

In other words, always trying to be dis-proven.

Theories are no less truthful than laws. The two serve different purposes, and are entirely different ways of explaining the world. Theories don't become laws when they are "proven," theories aren't just guess waiting to be proven or disproven. No one is trying to disprove relativity. They may be disagreeing on why the things relativity is describing happen, but that doesn't mean that what relativity describes doesn't really happen. Theories don't have less "facts" to back them up than laws do, theories are different from laws... Read the thread Evolutionists are wrong! The earth is young. ("http://www.straightdope.com/ubb/Forum7/HTML/000214.html)

Theories are supported by every bit of evidence that points to them. Both time contraction and distance contraction, things predicted by relativity, are readily observable, as well as energy-mass equivalency (atomic bomb, the sun, etc. etc.) and gravitational effects on light. Theories don't become accepted theories unless they are completely supported by evidence. Now, that also doesn't mean that everything that Einstein said is still accepted as correct (he once said of quantum mechanics "God soesn't play dice with the universe." but later himself recanted and came to accept QM as a valid means of explaining some very bizzare behaviors) but the general ideas of what the theory tells us (about energy and matter, etc. etc.) are still observably accurate.

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Jason R Remy

"One pill makes you taller, and one pill makes you small, but the ones that mother gives you don't do anything at all"
-- Jefferson Airplane White Rabbit (Slick, G. 1966)

[Undead Dude]

I'd like to commend jayron 32 for his bravery in trying to summarize that so concisely. It an ain't easy task to do that. :)

It's only a *theory* -- handy
Yeah, and it's only a theory that the universe exists too. :)
Relavitity is a very well established, well proven concept. At a future date, it my be updated and improved (in the same way that Einstein updated Newton's ideas), but it isn't going to be shown to be "wrong". All of the effects associated with special relativity have been observed over and over again. Most of the effects of general relativity have also been observed frequently.

1) Light moves at an absolute velocity. The velocity of light in a vacuum is a constant. -- jayron 32

Let me clarify this by saying that light moves at the exact same velocity in a vacuum for all observers regardless of their motion. That was the initial assumption that led Einstien to all of the cool fireworks in special relativity.

But you actually do make this point later on.


so light always appears to be moving the same speed regardless of what your absolute velocity is. -- jayron32
I know you are simplifiying, but I just felt the need to say that there ain't no such animal as "absolute velocity". There is only velocity relative to something else. But again, you do make this same point later on in the summary.

[Markxxx]

Thank you Jayron 32. IT was most helpful. So was the other alta vista link.

I guess the thing that I'm now wondering is if you were to get into some kind of, for lack of better word, spaceship, and travel near the speed of light. And come back to earth your body would age X years but everybody on earth would age Y years. Thus you'd in effect put yourself in some sort of time machine, putting yourself in what now looks like to you the future.

Also on another note, if you could, somehow disprove the speed of light is a constant, you'd pretty much destroy all the physics we now know, right?

[Czarcasm]

Causation of Big Bang-someone or something reaching the speed of light. Possible?

[Undead Dude]

I guess the thing that I'm now wondering is if you were to get into some kind of, for lack of better word, spaceship, and travel near the speed of light. And come back to earth your body would age X years but everybody on earth would age Y years. Thus you'd in effect put yourself in some sort of time machine, putting yourself in what now looks like to you the future. -- Markxxx
Yes, this effect can happen. It's commonly called the "twins paradox". The validity of this idea has been demonstrated by radioactive materials in cosmic rays and particle accelerators, which end up having an extended half-life due to fast motion.

Also on another note, if you could, somehow disprove the speed of light is a constant, you'd pretty much destroy all the physics we now know, right? -- Markxxx
Well, I'm assuming that you are specifically referring to the speed of light in a vacuum.

It probably would not destroy existing physics. It would need to be some bizarrely unusual case that allowed for the change, because in all of our observations of the universe, we have yet to see such a case. Such an idea would probably "update" our current view rather than destroy it.

[Undead Dude]

Causation of Big Bang-someone or something reaching the speed of light. Possible? -- slythe
Two probs with that.

First of all, reaching the speed of light really is impossible for a massive body. Conceptually, to the traveller, reaching the speed of light would be like reaching infinite speed. It is just as impossible.

Second, it is hard to talk about causes to the big bang, as cause implies the prior existence of an event, and the big bang is literally the beginning of time.

[Markxxx]

Time being an abstract thing. The big bang would be the beggining of time as we know it. How do we know that the universe, or matter that came from the big band didn't exist for millions of years prior to the big bang?

Secondly, you can probably guess where my next question is going...
It seems we could theoretically, use relativity to explain a form of time travel into the future. Is there anything on a parallel note that would let us, theoretically travel back in time.

Thanks for the answers guys. You have not only explained this stuff simple but you make it interesting too.

[Undead Dude]

Time being an abstract thing. The big bang would be the beggining of time as we know it. How do we know that the universe, or matter that came from the big band didn't exist for millions of years prior to the big bang? -- Markxxx
Well, time isn't that abstract. It is just as quantifiable as distance. As the big bang story goes, time and space were created as part of the big bang, so it's kinda hard to say "prior" when there is no time to be prior in.

It seems we could theoretically, use relativity to explain a form of time travel into the future. Is there anything on a parallel note that would let us, theoretically travel back in time. -- Markxxx
With relativity, travel forwards in time is a clear possibility. As far as travelling backwards in time, there are is a very unlikely senario involving a rapidly moving wormhole, but that assumes that wormholes really exist, and that it is possible to travel trough one. Surviving a trip through a wormhole looks about as likely as surviving the decent into a blak hole.

Of course then there is the problem of causality violation (the whole killing-your-parents-before-you-were-born thing), which leads most physicists to believe that travel backwards in time is almost certainly impossible, even if we have yet to prove it impossible.

[Markxxx]

Ok please explain what a wormhole is?

I heard the time travel problem explained as You could, but you won't cause you didn't. In other words you could kill your mother, but you won't kill your mother because you didn't kill your mother. Kinda a life is predestined thing.

Or another explains it as parallel universes. Or the second you kill your mother you would cease to exist

[EvilGhandi]

Jayron,
Kudos for your compressed version of realitivity. It has been some time since I have seen someone put it in laymans terms so succintcly. FYI for all your trouble it seems that mark is yanking your chain. Advise him to open a book.

[AWB]

Simplified Theory of Relativity: Time move slower when you're with your relatives. :)

[jayron 32]

Jayron,
Kudos for your compressed version of realitivity. It has been some time since I have
seen someone put it in laymans terms so succintcly. FYI for all your trouble it
seems that mark is yanking your chain. Advise him to open a book.

Thanks... I guess that's why I am in training to be a teacher.

But it really seems to me that Mark was genuinely interested in this stuff. As for a book to read, I HIGHLY recomend a book called "The Six Roads from Newton" by an author who I believe was Edward Spenser, but I could be wrong on the author. It is by far the best layman's explanation of advanced physics I have ever read. It covers both general and special relativity, quantum physics, probability, field theory, and the sixth one escapes me, but it is a very good book for introducing the non-mathematically inclined to some really neat physics. For the non-scientifically trained, this stuff can be confusing, since advanced physics (relativity and QM and probability physics and all that jazz) runs somewhat counter to experience, atleast somewhat counter to the aristotelian-newtonian physics that fits quite well with our experiential paradigm.

If you watch PBS or Discovery science shows, you see stuff like this thrown around all the time, but often it is either glazed over or so poorly explained that it leads to incomplete conclusions about the operation of the universe. Mark's questions are the exact sort of stuff that people tend to ask when confronted with this stuff.

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Jason R Remy

"One pill makes you taller, and one pill makes you small, but the ones that mother gives you don't do anything at all"
-- Jefferson Airplane White Rabbit (Slick, G. 1966)

[jayron 32]

I guess the thing that I'm now wondering is if you were to get into some kind of, for
lack of better word, spaceship, and travel near the speed of light. And come back to
earth your body would age X years but everybody on earth would age Y years. Thus
you'd in effect put yourself in some sort of time machine, putting yourself in what now
looks like to you the future.

Again, not exactly. Since velocity is the constant in our equations, rather than your velocity depending on the time and distance you travel, it works the other way around. The time and distance you travel is variable and dependant on the velocity you use to get around. Your "frame of reference," which is defined as you and all of the stuff moving at your speed, will "age" (or advance through time) at the same rate, while everything else moving a different speed will "age" at a different rate. Thus, you don't actually "travel into the future" when you move faster, you experience the same stuff as everyone else, you just experience it faster (if it's in the "slower" frame of reference) or just like you weren't moving (if it is in your frame of reference). BTW, don't think by running down the street you can lengthen your life by increasing your time contraction (Jim Fixx proved us wrong on this one, hardy har har.) In order to witness time contraction on a level that would make a difference, you'd have to travel millions of miles per hour faster than everyone else. The phenonmenon has been witnessed on supersonic flights (~800 mph) but only on the order of nanoseconds per hour of flight time.

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Jason R Remy

"One pill makes you taller, and one pill makes you small, but the ones that mother gives you don't do anything at all"
-- Jefferson Airplane White Rabbit (Slick, G. 1966)

[jayron 32]

Time being an abstract thing. The big bang would be the beggining of time as we know
it. How do we know that the universe, or matter that came from the big band didn't
exist for millions of years prior to the big bang?


Actually, time is a very real thing. You can look at time as "the rate at which things in your frame of reference do stuff" You can observe, for instance, that it takes so long for a ball to roll down an inclined plane. The units for measuring time are quite man-made, but in so far as events occur in order, and have a causal relationship ("A" must occur before "B" can) time is a real thing. At least in the macrophysical world. Particle physicists have a different idea about time and causality all together, but they're a weird crowd anyways.

Since, before the big bang, there wasn't anything to happen, there was also no "time" for it to occur in. Time and space are, as one way to put it, a symptom of the same property... Since there is a place to go, it takes time to get there...

Oh, and as to moving backwards through time, there is one theory that states that anti-matter (which is quite a real thing and can be observed right here on earth) is simply matter moving backwards through time. Suffice it to say that such a statement simply relies on the creative placement of a floating negative sign. I told you that particle physics crowd was a hoot.

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Jason R Remy

"One pill makes you taller, and one pill makes you small, but the ones that mother gives you don't do anything at all"
-- Jefferson Airplane White Rabbit (Slick, G. 1966)

[Markxxx]

Hey guys now c'mon

First of all I did look on the "net" that is why I asked in the orginal question could you put a more simplified version. I had looked but only found versions that were textbooked or really so far off beat they didn't appear to be true.

Second I thanked both the orginal two people providing me with a link and explination

Third, that ask a question link is really no better than your average search engin. I know about it.

Lastly, it is important to ask questions because you get things explained to you and if you are wrong you are shown the error of your reasoning. For a good example on my question on time travel I was told one thing by one reply, and later was advised that is essentially NOT correct. So if I had mearly gone to a link I may get one answer that agrees with my logic and never be shown it is faulty. Remember anyone can put any misinformtion or garbage on the net.

Now this brings me to this question. Could some sort of universe existed spead out, collapsed and then we have a big bang from that collapsed matter? Thus there would be a "Time" frame during that period where nothing would exist.

[Undead Dude]

Thus, you don't actually "travel into the future" when you move faster, you experience the same stuff as everyone else, you just experience it faster (if it's in the "slower" frame of reference) or just like you weren't moving (if it is in your frame of reference). -- jayron 32
Well, there is no need to define time travel into the future as a teleporting leap. It could be a smooth process, just as in The Time Machine by H.G. Welles. I think it is perfectly reasonable to call the "twins paradox" effect time travel into the future.

And also, while you are travelling at high speeds relative to your friends, you actually see their actions going slower rather than faster. The net effect of you observing their events going faster happens in a sudden burst when you decelerate down from your fast speed.


Now this brings me to this question. Could some sort of universe existed spead out, collapsed and then we have a big bang from that collapsed matter? Thus there would be a "Time" frame during that period where nothing would exist. -- Markxxx
This idea has often been thrown around, but it is really beyond the perview of physics to tackle that. That is more of an issue for philosophy. It is inherently impossible for us to attempt to detect such a possibility. My personal feeling is that the idea is just a natural trap of the mind-- that we find it hard to accept that there could be a beginning or end of time itself. Of course the idea that the universe might collapse is on the wane right now. Discoveries in recent years have brought the vast majority of cosmologists and astronomers to believe that the universe will expand forever.

[Undead Dude]

Oh, and as to moving backwards through time, there is one theory that states that anti-matter (which is quite a real thing and can be observed right here on earth) is simply matter moving backwards through time. -- jayron 32
Yeah, that is a kinda goofy, fanciful idea that largely results from the time-symmetry of most interactions. I think this idea will be killed when we gain use of anti-matter sophisticated enough to demonstrate that the entropy of anti-matter increases in the same time direction as regular matter.

[Undead Dude]

Again, not exactly. Since velocity is the constant in our equations, rather than
your velocity depending on the time and distance you travel, it works the other way around. -- jayron 32

I'm a little bit confused by this correction.

Let me put forth an example that is possible within relativity, which I think fairly well matches what Markxxx is saying.


Joe and Bob are on Earth together. Joe leaves the Earth, reaching the point that he is travelling very, very close to the speed of light from Bob's (the Earth's) perspective. Joe continues his voyage for 6 months, and when he returns to Earth, Bob is dead because 100 years have passed on Earth.

Is this different from what Markxxx was asking? By my definition of time travel, this is time travel into the future.

[jayron 32]

s this different from what Markxxx was asking? By my definition of time travel, this is time travel into
the future.

Well, again it depends on whether you define time-travel as simply progressing through a frame of reference that is moving at a different rate OR actually skipping a period of time and reappearing in a future time. If you wish to define it however you feel makes it most convenient for you to convince youself it can occur, go ahead.

I'm a little bit confused by this correction.

OK, try it this way: At speeds near the speed of light, the time of your frame of reference slows down and the distance between where you are and where you are going shrinks. The result is two fold: Nothing happens to the stuff in your frame of reference, and the rest of the world whizzes by at a much faster rate of time. If this is time travel, so be it. But you haven't jumped through time, you've just moved faster than everyone else. "Travel" implies reversablity; if you can get there you can get back. So far, there is no way I know of to go "backwards" through time. The near-lightspeed "time travel" is no different than the kind of time travel we commit now, that is always forward, at a rate that is determined by the relative difference in speed between us and something else.

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Jason R Remy

"One pill makes you taller, and one pill makes you small, but the ones that mother gives you don't do anything at all"
-- Jefferson Airplane White Rabbit (Slick, G. 1966)

[Undead Dude]

Clearly this is primarily a difference in definitions of what time travel is. Few comments here tho...

Nothing happens to the stuff in your frame of reference, and the rest of the world whizzes by at a much faster rate of time. -- jayron 32
Unless I am misinterpreting what you are saying, this is wrong.

While you are whizzing away from Earth at close to the speed of light, you do not see events on Earth going faster. As a matter of fact, you see them to go slower. Likewise, observers on Earth see that time for you is going slower.


If this is time travel, so be it. But you haven't jumped through time, you've just moved faster than everyone else. -- jayron 32
Agreed here.

"Travel" implies reversablity; -- jayron 32
I'm not sure why you place this restriction on the definition of travel. It isn't an implication I feel in the definition, and that implication doesn't seem to be reflected in my dictionaries.

[handy]

Mark, whenever you have a question just ask
at www.ask.com (http://www.ask.com) You'll find the answer, its a pretty spiffy search engine, I use it all the time.

Let's all try to disprove the 'Special Theory of Relativity':
The Special Theory has withstood the scrutiny of countless
investigators over the past ninety years and has become one
of the intellectual cornerstones of modern physics. Despite
this, it is contended that the kinematic aspects of the theory
contain a number of serious philosophical and logical
inconsistencies which effectively nullify it as a basis for
dynamic considerations.

Among these are the unsatisfactory interpretation of the first
postulate, the arbitrary limitations imposed on the means to
determine synchronism and simultaneity, and the total
exclusion of one-dimensional aspects in the justification for,
and calculation of space-time modifications.

............ack

[Undead Dude]

Ok please explain what a wormhole is? -- Markxxx
First of all, I would like to say that the idea of a wormhole is extremely speculative. It is a valid use of general relativity on paper, but no real evidence is out there to support their existence, and finding such evidence would be very difficult, as they would resemble black holes.

A black hole can be described as being like a funnel in space-time. A wormhole would be like two of these funnels connecting at the bottom, resulting in a bridge between two points in space-time.

[Undead Dude]

In other words you could kill your mother, but you won't kill your mother because you didn't kill your mother. Kinda a life is predestined thing. -- Markxxx
Yes, this is a valid logical escape from causality violation. If it weren't for this escape, we could logically say that time travel was impossible in a proof by contradiction. The only problem is that it lacks any physical explanation as to why you wouldn't be able to commit the violation. Simply invoking predestination isn't very scientifically convincing.

Or another explains it as parallel universes. Or the second you kill your mother you would cease to exist -- Markxxx
AFAIK, this idea is based on nothing more than the fertile imaginations of science fiction writers. :)

[the first supraliminal]

Joe and Bob are on Earth together. Joe leaves the Earth, reaching the point that he is travelling very, very close to the speed of light from Bob's (the Earth's) perspective. Joe continues his voyage for 6 months, and when he returns to Earth, Bob is dead because 100 years have passed on Earth.


All things relative, it can just as easily be shown that Joe is stationary, and Bob and the Earth are travelling very, very close to the speed of light from Joe's perspective. And when Bob and the Earth return, Bob finds Joe dead because 100 years have passed with Joe.

According to relativity, both cases are true, when clearly they cannot be. Hence, the twin paradox.

There is something inherent in the nature of acceleration that chooses preference of one case over the other. We still don't know what it is. And the assumptions of relativity may be wrong, or incomplete.



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¾È ³ç, ÁÖ µ¿ ÀÏ

[Undead Dude]

According to relativity, both cases are true, when clearly they cannot be. Hence,
the twin paradox.

There is something inherent in the nature of acceleration that chooses preference of one case over the other. -- Beeruser
Hi, Beeruser! I've been looking for the convo we had about this in old posts but I can't find it. :)

There is no actual paradox. As with many paradoxes, there only seems to be a conflict on the surface. While acceleration is what makes the decision for us as to who ages and who doesn't age as much, it isn't a mystery. The only reason that acceleration is so special here is because acceleration is the process of changing reference frames. In relativity, it is fine to have two rates of time be in disagreement with each other in two different inertial reference frames. The disagreement only needs to be resolved if they both end up in the same reference frame. Since Joe ends up back in Bob's reference frame, then Bob's reference frame becomes the agreed result.

All things relative, it can just as easily be shown that Joe is stationary, and
Bob and the Earth are travelling very, very close to the speed of light from Joe's perspective. And when Bob and the Earth return, Bob finds Joe dead because 100 years have passed with Joe. -- Beeruser

In the example above, it is not valid to say that Bob finds Joe dead, because Bob has not changed reference frames. Bob and the Earth do not accelerate in this senario. While you cannot say that one inertial reference frame is absolutely moving while another reference frame is absolutely still, you most certainly can say that a given reference frame absolutely is accelerating or absolutely is not accelerating. This came up in the recent Relativity vs. Radial Motion thread.

[the first supraliminal]

Thanks, Undead Dude, howcome you didn't explain it before? :)

The last physics textbook I read called it a paradox, but that was ten years ago. I guess they resolved it? On second thought it may have been just pointing out how they resolved the paradox. But it did mention something inherent about acceleration that wasn't known yet.



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¾È ³ç, ÁÖ µ¿ ÀÏ

[Undead Dude]

Thanks, Undead Dude, howcome you didn't explain it before? -- Beeruser
LOL! I guess this context made it come out better. :) I think last time I was more obsessed with giving a visual picture of what was going on.

The last physics textbook I read called it a paradox, but that was ten years ago. I guess they resolved it? -- Beeruser
It was never truly a mystery. I think the concept of the twins paradox was devised as a way to explain the potentially wild implications of relativity, and the word paradox was used because it would certainly sound like a paradox to the listener. Seems like the word paradox is used like that a lot.