Pete and Anna both have a spaceship and wants to test relativity. So they both rig a transmitter with which they will send a beep to each other once a second. Pete starts flying off in some direction and swiftly reaches a very high speed. Anna seems to be getting the beeps once every two seconds, time must be flowing half as fast for Pete. Pete recieves Annas beeps once every two seconds so from Pete's point of view Anna is ageing half as fast. Now Pete turns back and approach Anna with the same speed as before. Now they both think the other one is ageing twice as fast. When they get back together the effects cancel out, when they meet up they will see that them both have aged as much.

There was a test with two airplanes with atomic clocks on board. One took off in the same direction that the earth rotates and the other one took off in the other direction. How can the effects not cancel out? Consider this: They both spend half the time travelling AWAY from ground base and half the time travelling TOWARDS it, flying around the globe. The planes do the same in respect to each other. So tell me, in the end, how can the time dilation effects not cancel out?

Time dilation calculations are not affected if the object travelling towards or away from you. It is only yhe magnitude of the velocity in your line of sight that matters.
Also the observer in the rocket will age less, since it is him that experiences acceleration of the rocket.

Of course it matters if they're travelling towards or away from each other. In one case there will be a redshift and time will appear to run slower. In the other case there will be a blueshift and time will appear to run faster.

No, No,No

In the time dialtion formula, the velocity is squared, and thus only its magnitude matters, not its direction.

So if someone is coming towards me very fast. It will seem like he is ageing faster but he is really ageing slower? Looks like a contradiction to me!

Originally posted by AndersHermansson
So if someone is coming towards me very fast. It will seem like he is ageing faster but he is really ageing slower? Looks like a contradiction to me!

No, we are talking about two different effects. One is the Doppler effect (where time appears to move slower when the object moves away and faster when approaching) and time dilation (Where an time moves more slowly due to velocity alone and is independant of direction). What you would see is a combination of both or "Relativistic Doppler" shift.

Ok, thanks for clearing that up.

Time is ultimatly a concept of man... its not something you can dilate or bend. (my theory has it that way anyway) Do you (meaning anyone reading this) believe everything you hear only because "the smart scientist with a Phd" said so? Have you done experiments yourself? And I know it sounds like I'm going against alot of what Einstine has said... but alot of the things he has said.. sounds more like "religious science." (or in other words.. "you must believe my radical theory only because I said it was right") Just an interesting thought.. for thoughs whos thoughts aren't "Tv dinners that have been pre-cooked pre-spiced" and all else, something you keep eating so you will never discover the real food for thought".

ManmadeUFOs:

<i>Time is ultimatly a concept of man... its not something you can dilate or bend. (my theory has it that way anyway)</i>

Please post your theory here, with supporting evidence.

<i>Do you (meaning anyone reading this) believe everything you hear only because "the smart scientist with a Phd" said so?</i>

No. Do you believe everything you read on crackpot websites?

<i>Have you done experiments yourself?</i>

Yep. Have you?

<i>And I know it sounds like I'm going against alot of what Einstine has said... but alot of the things he has said.. sounds more like "religious science."</i>

Experimental evidence supports relativity.

<i>(or in other words.. "you must believe my radical theory only because I said it was right") </i>

Do you really think a theory would stand for 100 years against all challenges if it was based only on some kind of aura of authority? For that matter, why do you think people believed Einstein after he first published his theory? He was only a patent clerk at the time.

Lets step back and "look at time". We see time as the movement of the planets, clocks and the like... it doesn't matter how fast you go,(even the speed of light) the bloody clocks and the planets are going to go the same speed. All you've done when you've travelled at the speed of light is increase the effiency in which you use your "time." And I know my explanation sounds extremely elementary, but isn't it the simple truth?
Well.. you tell me to do an experiment. Tell me then, how does one go about that? (doing some sort of time experiment like Einstine) Well?

Oh and let us not look at how crapy you or I may be at arguing in the forums, let us address the point. (tell me why time dilation is possible...then perhaps you will have a new believer)

James R,

I really can't believe that you actually think this sort of thing is appropriate in your physics forum. Quite a while ago, the members on this board voted, and came to a conlusion that a theory development forum was in order. This clearly belong there. Why have you not done what the membership wanted done?

- Warren

Originally posted by ManmadeUFOs
tell me why time dilation is possible...then perhaps you will have a new believer Time dilation has been measured and observed, it is therefore possible.

ManmadeUFOs:

<i>Lets step back and "look at time". We see time as the movement of the planets, clocks and the like... it doesn't matter how fast you go,(even the speed of light) the bloody clocks and the planets are going to go the same speed.</i>

Not true. You need to study relativity.

<i>All you've done when you've travelled at the speed of light is increase the effiency in which you use your "time."</i>

What do you mean by that?

<i>Well.. you tell me to do an experiment. Tell me then, how does one go about that? (doing some sort of time experiment like Einstine) Well?</i>

Do a Google search for "Experimental basis of relativity". You'll find all kinds of real experiments which back up Einstein's theory.


chroot:

<i>I really can't believe that you actually think this sort of thing is appropriate in your physics forum.</i>

Part of the purpose of this forum is to educate.

<i>Quite a while ago, the members on this board voted, and came to a conlusion that a theory development forum was in order.</i>

Yes. See my response in the "Alternative theories policy" thread.

<i>Why have you not done what the membership wanted done?</i>

I am not empowered to create new forums, even if I thought that was appropriate.

But why does any of this concern you, chroot? Didn't you say there was nothing here for you and therefore you were moving to physicsforums.com and leaving sciforums behind? Why are you back?

So James,

You've asked us to vote on things you don't even have the power to enforce? What's the point?

Also, are you really saying that you'd rather have people like ManmadeUFO here than people like me? That's laughable. This is a SCIENCE website. Not pseudoscience, not quackery.

I understand and appreciate that indeed, much of the purpose of this site is for those who have knowledge to pass it on to others. In fact, I think I've done that quite well many times in the past. However, I don't see that arrangement working too well with some of the resident crackpots -- do you?

Essentially, I'm asking you directly -- what do you feel MacM does to benefit this community? You yourself have gotten passive-aggressive with him many times for his habit of demanding a response, ignoring it, and continuing to claim victory. Virtually all that happens on this forum is about five people arguing what is obviously a hopeless case -- MacM. The same exact arguments and responses have been given half a dozen times now. Is this really the sort of thing you want on your message board?

Does the website have a charter? If not, should it have one? If so, does (or would) MacM really meet the purposes of the charter?

- Warren

It's cool chroot. Mac actually makes me feel good because I realise how much I know compared to him. I think we just have to learn to ignore some of his more erroneous statements.

chroot:

<i>You've asked us to vote on things you don't even have the power to enforce? What's the point?</i>

I wanted to gauge the general feeling on the forum. I am just as justified in posting polls as anybody else here. I am a contributor to the forum as much as I am a moderator.

<i>Also, are you really saying that you'd rather have people like ManmadeUFO here than people like me? That's laughable. This is a SCIENCE website. Not pseudoscience, not quackery.</i>

I have never said that I do not want you here, chroot. Nor have I ever said that I'd rather have some other poster here. I do not play favorites. As I recall, <b>you</b> were the one who decided to leave for a while. But you came back. That suggests to me that there must be something here for you.

<i>I understand and appreciate that indeed, much of the purpose of this site is for those who have knowledge to pass it on to others. In fact, I think I've done that quite well many times in the past.</i>

Yes, you have. I appreciate your knowledge and your input.

<i>However, I don't see that arrangement working too well with some of the resident crackpots -- do you?</i>

No. Some people you'll never convince. So ask yourself - who are you writing for when you respond to a crackpot? For me, it's partly in the hope that I can change their mind. The other (usually more important) part is that many other people read these threads apart from the crackpots. They can learn things and judge for themselves.

<i>Essentially, I'm asking you directly -- what do you feel MacM does to benefit this community?</i>

Look at the history of MacM's threads. They have led to useful discussions of relativity, and have forced those who know relativity to seriously consider some hypothetical scenarios. Hopefully, this has help them to solidify their understanding of the subject. Hopefully, it has also helped observers learn a bit about relativity which they may not have known before.

I am still waiting for a really good explanation of MacM's merry-go-round problem. That discussion seems to have descended to "I'm right." "Not you're not." "Yes I am. I posted the explanation before." "No you didn't." "Yes I did." etc. The relativity crowd should be able to do better than this. (I might eventually have a go at it myself.)

<i>You yourself have gotten passive-aggressive with him many times for his habit of demanding a response, ignoring it, and continuing to claim victory. Virtually all that happens on this forum is about five people arguing what is obviously a hopeless case -- MacM. The same exact arguments and responses have been given half a dozen times now.</i>

Yes. It's a bit wasteful, isn't it? Those who have posted correct and complete answers should be content to move on. Of course, it's entirely up to them as to when they feel they've said enough.

<i>Is this really the sort of thing you want on your message board?</i>

Informative discussion and clarification of concepts from people who know what they're talking about? Of course.

<i>Does the website have a charter?</i>

I don't think so. Not a specific one.

<i>If not, should it have one? If so, does (or would) MacM really meet the purposes of the charter?</i>

Good questions. Perhaps you could suggest a charter...

James R.,

I am still waiting for a really good explanation of MacM's merry-go-round problem. That discussion seems to have descended to "I'm right." "Not you're not." "Yes I am. I posted the explanation before." "No you didn't." "Yes I did." etc. The relativity crowd should be able to do better than this. (I might eventually have a go at it myself.)


ANS:Good show. I have posted something on this issue under topic "MacM's Claims". Think you all might just want a read.

Originally posted by James R
I do not play favorites.

not even me, james? hehe, just kidding.

but seriously:

<i>However, I don't see that arrangement working too well with some of the resident crackpots -- do you?</i>

No. Some people you'll never convince. So ask yourself - who are you writing for when you respond to a crackpot? For me, it's partly in the hope that I can change their mind. The other (usually more important) part is that many other people read these threads apart from the crackpots. They can learn things and judge for themselves.

this raises an interesting question. one of the problems with too much crackpottery on the boards, is that it floods the front page, to the exclusion of all legitimate threads. i have complained about this before, and when it happens, i get rather disgusted with this place, and stop coming as much.

but in a sense, are the people who cater to the crackpots as much to blame for the dilution of the board as the crackpots? if you keep arguing ad infinitum with the crackpots, instead of just letting his crackpottery fall on deaf ears, you too are contributing to that dilution.

personally, if you hate the crackpots, just ignore them. if enough people follow suit, they will all be gone, their threads will drop like rocks.


<i>Essentially, I'm asking you directly -- what do you feel MacM does to benefit this community?</i>

Look at the history of MacM's threads. They have led to useful discussions of relativity, and have forced those who know relativity to seriously consider some hypothetical scenarios. Hopefully, this has help them to solidify their understanding of the subject. Hopefully, it has also helped observers learn a bit about relativity which they may not have known before.

i consider this a weak argument. even if he has been the source of some fruitful discussions, his signal to noise ratio is horrible. he s almost at 1 000 posts now. how many fruitful discussions do you think have arisen since his arrival?

but, we ve been over this. i know how you feel about it: if the cost is the loss of one single fruitful post out of 1 000, then it is worth it. so let s move on.


I am still waiting for a really good explanation of MacM's merry-go-round problem.

all answers can be found on the physics FAQ (http://math.ucr.edu/home/baez/physics/). rotating disk here (http://math.ucr.edu/home/baez/physics/Relativity/SR/rigid_disk.html), turns out that it s actually a pretty difficult calculation in its full GR generality, but that page will give you the basic idea. feel free to read it and then do battle with Mac on the merry-go-round problem. he is positive that he won that argument. i ll be honest, i never even read that thread. those crackpot debates give me a headache when they get over 50 posts.

if i see anyone say that &pi; changes again, though, i m going to start ripping my hair out. GOT THAT PEOPLE! &pi; never changes! the ratio of a circumference to its diameter might change, but not &pi;, so please!

lethe,


his signal to noise ratio is horrible.

ANS: This comment did give me a chuckle.

Now to your post. I did find three things interesting here.

This is the opening statement of your link:


1 - "In this entry, I summarize what I know of the literature, and invite others to fill in the gaps. Surely such a celebrated problem should have found a definitive resolution by now. But the tale I have to tell ends on an incomplete note. We look at SR first, then GR."


ANS: Why would you think this link provides the answer when that author states it ends "incomplete"? And I did read the entire paper, not just the heading and conclusion, OK and it doesn't provide the answer.

Actually if it did, it wouldn't:D

I'll let that statement tantilize you for a while before I give you the answer (unless you have already read "MacM's Claims".

2 -Einstein's 1916 paper on GR [5] makes no mention of elevators; instead, the Equivalence Principle is introduced via the rotating disk


ANS: I used centrifugal force to illustrate the "Equivelence Principle" And most everyone, including you James, told me how dumb I was. Now lets go tell old dumb Al how he is screwed up.


3 - Somewhere back in this long series of strings I used the concept of a massless super solid rod as being an analogy to FTL in the issue of particle entanglement. Boy did that stir up the mob.

Old Crackpot MacM, at it again. "Claiming a massles , supersolid rod". Lets keep it at least plauseable eh?

Don't you find it strange that this is the very technique used in the m-g-r analysis? A solid massless disk where compression waves are ignored.

Doesn't that ring a bell back there somewhere? Did I not state the exact same conditions in my analogy of the solid rod theory of particle entanglement; which each of you objected to?

CONCLUSION:

Still think Old MacM is the Crackpot of all times?

Well stay tuned you are going to see many more foo-paaas you guys made because you thought you were dealing with an ignoramous.:D

I'm not angry. I'm having fun. How about you?

I'm not having fun, I'm bored. Is there any chance we could discuss something not related to relativity and quantum entanglement. This forum should be renamed

"Discussions on the misconceptions of individuals concerning relativity."

Originally posted by MacM

CONCLUSION:

Still think Old MacM is the Crackpot of all times?

Well stay tuned you are going to see many more foo-paaas you guys made because you thought you were dealing with an ignoramous.:D

I'm not angry. I'm having fun. How about you?

Mac, yes, i still think you re a crackpot. no, i don t find this debate fun at all. i am also not angry, just bored with the whole debate. i have no intention of addressing your points. maybe james has the wherewithal.

ryans & lethe,

Interesting responses. You see there really is no debate you have been chasing your tails for months. And I happen to agree with James R., and that is it hasn't been for naught.

I have caused you to do some digging and presenting points that otherwise would not have been done but primarily I hope you at least have learned that you shouldn't jump to conclusions so fast and should keep your arguements focused in the issues.

I do agree it is time to move on. Sorry you are pissed off ryans but it couldn't happen to a nicer guy, unless maybe ch:D

Me? I'm still going back and having a good laugh. I think it wqs great fun, just hope we don't have to do it all over again.