Time dilation

[Nuri]

Alex,

We can't prove or disprove that "nothing" existed before the bang. However, we do have cosmic radiation measurements of a big bang 13.7 billion years ago, and other physical evidence that supports expansion. But we cannot (currently) measure what existed before the big bang. Sure, we can argue what "was" or "wasn't", but it would all be pure speculation. Given that most of what we DO know about the universe is less than 50 years old and that we are regularly discovering that we actually know bugger all (eg. "event horizons"), it's safe to say we've probably discovered only a fraction anyway

Re: "perception" vs. "real" time dilation, the view that makes the most sense to me in this thread is this by AGarvin on the previous page :

Basically, it centres around the fact that the speed of light is the same for all observers. The stationary observer will see the light travel further than the person in the ship will for the same event. If the distance is further, but the velocity is the same, then the time taken must be 'longer', or dilated.

To me, this is not a perception. Assuming that C is definitely constant, the observer will actually live longer than the traveller during the period of the experiment. But if nothing can move faster than C, then we get the paradoxes mentioned earlier, like not being able to "see" your hand in front of you travelling at C.

... As I said, we know bugger all... but tallking about it is a *great* way to produce sparks!

[mickoking]

IMHO I belive something did exist before the Big Bang. It makes no sense to say something (the universe) was born from nothing. Cause and effect.

[xelasnave]

I am not unaware of the background radiation data, what if that is missinterpreted data... maybe its the radiation from beyond what we call our observable Universe or something else... however it fits the expectations of an extrapolation to a point drawn backwards from the observation of an expanding Universe.Now although totally against the grain expansion to me does not add up... the question "into what medium does it expand into" until answered in my mind will leave me at that point.
The two alternatives..firstly that the Universe has always been and always will be and the second that the Universe started at a point smaller than a grain of sand and within the grain of sand all was contained all to build todays Universe..either is not easy to accept.
Our time at the problem is miniscule to the enormity of what we seek to know as you have observed.
Thank you for your input and statement of your understandings and belief
alex

[Doug]

Pardon me chiming in rather late in the piece, but I have issues with time dilation, and the experiments that are supposed to 'prove' same.
I have been informed of two different experiments, both of which are supposed to support time dilation, but (I think) neither results agree on degree.
The first experiment involved Jet setting one clock around the world and noting a slight dfference in their time readings. The second test involve taking one of two synched clocks from Greenwich and leaving it atop a rather high mountain for a year, then comparing the two.
The first test was acclaimed a sucsessful demo of time dilation due to V.
The second test was aclaimed as proof of time dilation as a direct result of G. Which test is really demonstrating time dilation if indeed either?
Just how scientific are those tests?

If velocity causes Time dilation, the many cycles (East to West orbits) would be necessary in order to produce a statistically unblemished result. For example 500 East to West orbits in a satelite, would tend to reduce any effect of delta v and delta g on the data collected. It is not that these factors I mention must have any effect on time, but they very well might exert influences on the atomic resonance frequency, possibly due to minute changes in the physical size of the cesium chamber, or maybe even on the resonance behaviour of the cesium atoms themselves.

If Gravity caused time dilation, then to be statistically certain of the accuracy of the data, perhaps many tests at various levels of G would be required. But as Earth bound altitude increases, so does V, so this test could become rather messy by its very nature. Perhaps a clock left on the Moon (West to East orbit) for a few decades might be statistically pure enough for such determinations.

So I think time dilation is as yet unproven scientifically, unless statistically sound tests similar to what I have suggested have indeed been carried out, and I haven't heard of any such.

Cheers,
Doug

[xelasnave]

I have yet to do more on this but I am confident I will get to the bottom of it.
The weight of opinion that it exists as a real thing is overpowering it is a pity that hte experiments can not provide more samples... I am prepared to conceed (and I have) that the "unsatisfyingly small measurements" involved are suitable and sufficient for physists who are more capable of assessing the data... however the sample issue or the lack of suitable samples to me is unscientific... the experiments of which we speak would carry more weight for me if we had say 100 clocks on the mountains of the world and a clock in every aircraft ... who will be the first to say that is an unreasonable expectation. I look all the time on the net re this stuff and you either get the for or against, if you are for you will only support the proposition if you are against you are outside mainstream and that puts you (and I must say usually correctly so) in the fringe where no one wants to say they are your friend.
The issue is important to me and has assumed obsessional proportions (as has gravity, the Universe nature and the line up of gallaxies) but I feel I can still give something fair scrutiny without bias.
I welcome your late entry and input your views are of interest to me and I thank you for taking the time to share them. This is an easy area to avoid because to offer counter views brings the glance of folk who will instanly believe they know more than you possibly could on the matter, and I know there is a tendancy to "look down" upon one who does not buy the proposition as if one were uninformed and bordering on crack pot.
Fortunately to be called acrack pot is a step up for me, thats higher recognition than I am used to so I really dont care if I anm labled such.
alex

[Doug]

I should have discussed the possibility of the frailty of Atomic clocks with a tad more clarity.
I suspect that "Elastic Inertial Compression and Rarefaction" due to delta v, will very likely be present, and its effects will also probably be as statistically uncertain of proof as are current time dilation tests themselves.

Cheers,
Doug

[AGarvin]

http://math.ucr.edu/home/baez/physic...periments.html

[xelasnave]

Great stuff . I have been there before refferred for help with my nonbeliever ways. I thought I recognised the name (Baez) you may like this .
http://math.ucr.edu/home/baez/crackpot.html
I failed it first time but I have been studying and will be trying for a higher score next time
Thanks for posting that link there is not much missing there.
alex

[xelasnave]

Hey should I take this personally??? (from the index)

"20 points for naming something after yourself. (E.g., talking about the "The Evans Field Equation" when your name happens to be Evans.)"
So the gravity rain thing has to be renamed "the xelasnave theory of UNIVERSAL PRESSURE"
(you get more point the more capitals one uses so I am catching on ) I found it (the index) personally helpful as I thought my symtoms were simple cabin madness but it was grander than that it seems .
Hope you get a laugh going thru it (the crack pot index) .
There is also a description for my problem "morosophic" where one sees every piece of new information that presents as being supportive of ones ideas. Hence my Professor Morosopher title in the gravity thing at astronomydaily.
All of this helps keep things for me where they should be but it does not frighten me from enquirey and objection I enjoy the area too much to be frightened away. Time for another quote from the Doctor and what Stephen Hawkins said about black hole radiation .
alex

[Doug]

Good Grief man! I glad you posted that last link. I was begining to think I would have to take him seriously. The mind that would revel in such basic ridicule is not a mind to be trusted.

I found this staement on his previous page of signal interest.

"They flew atomic clocks on commercial airliners around the world in both directions, and compared the time elapsed on the airborne clocks with the time elapsed on an earthbound clock (USNO). Their eastbound clock lost 59 ns on the USNO clock; their westbound clock gained 273 ns; these agree with GR predictions to well within their experimental resolution and uncertainties (which total about 25 ns)."

I think this above contribution by Baez justifies skeptical reception of much so called scientific proof by honest enquirers.

Let us assume that these flites were both non stop global circuits (which they very likely were not).
Let us assume that the East bound clock did in fact loose 59ns. and let us assume that there was neither head wind nor tail wind(since no data is cited) Let us further assume that the flight took place at near enough to zero latitude and that the airspeed hence ground speed was 500km/hour.
Further, let us assume an equatorial circumference for the Earth of 42,000km and this figure including the increased circumpherence due to the flight altitude.
So after a flight time of 80 hours our east bound clock will have travelled the 40,000 km circuit required to bring it back to its point of origen.
And so after 3 1/3 days it has lost 59ns.

Now what about the west bound clock? The aircraft carrying this second cloch also has an air speed of 500km/h, hence a ground speed the same.
But because the second clock is being flown in a direction 180d opposed to the point of origen, the overall flight time will be shorter than it was for the East bound clock. therefore any hypothetical time dilation will be of lesser extent than for the east bound flight. Since 'sence' is missing from the GR equations, if this test had indeed agreed with the theory of GR, the west bound clock would surely have lost some time, but not as much as the 59ns lost by the east bound clock.

You see this so called experiment has introduced direction into the arguement, such that the best match to it would be that if a space ship travelled to aCentauri, on board time would be compressed, but on the return flight, time would be stretched back again, but by a greater amount. ;that is if aCentauri lies to our east??
That is where the data supplied by Baez leads us. But don't worry, you can go as far as you like at light speed, just don't think of comming back!

So the data supplied taken at face value, suggests that a space craft travelling east, then returning would actually return before it left................I think not!

Maybe time dilation only exists on planets?? after all, east and west have no meaning in space.

I remain very much unconvinced of time dilation not only by the appauling lack of statistically compelling data, but also by the tawdry attitude presented by one of its cheif appologists as shown by the link you supplied Alex.

cheers,
Doug

[Shawn]

Time dilation is something we say that happens under certain circumstances, so that we dont contradict the c=constant that underpins our understanding of the universe. and upset a whole bunch of genies arses to boot. Where as c being constant contradicts our obervations under certain circumstances. since we base our measurement of time on c being constant, this discussion could go on forever, ie time dilated ...all of the anomolies and paradoxes could be explained if c is not constant. It really couldnt be any simpler could it..... That should stir things up a bit, hey what old chap... .

[Shawn]

I guess what Im saying here is that light obeyes the same laws of physics than everything else, tho limited by its infinitesimally small mass" and there is another subject of debate" take for example gravitational lensing, or even chromatic abberation,,a bit extreme...but yes different distances same time..if you could ever measure it,, its all relevant..we measure huge distances by red shift. is it not possible that light does gradually slow down and that these objects are not as far away as we measure them to be. the distances are overwhelming, we cannot expect to get an accurate picture in our tiny neck of the woods...

Ive repeated myself somewhere Im sure, Id like to know just how many others think that just maybe, what we think we know is based on a theory that is fundamentally flawed..

[Doug]

I'll put my hand up .
But wait..........Gravitational lensing?? Now see here, we have sent out interstellar SOHOs to accurately analyse and measure the exact composition and density, refractive index and countless other properties of distant stellar atmospheres. We know to a high degree of accuracy just how much light from a more distant occulted star will be refractd and this just does not account for the observed shift. This clearly proves gravitational lensing, which of course proves beyond reasonable doubt that gravity interacts with light..................I think not.

Eric Von Danekin (sp) astounded a fact starved world with the cosmically important revelation that the hight of some Pyramid or other was some fraction or other of the distance from it to the Sun. Wow!
And these observed stellar shifts agree (within experemental limits of course) with relativity predictions of gravitational effect on light; so Q.E.D.?? talk about clutching at straws.

[AGarvin]

Now what about the west bound clock? The aircraft carrying this second cloch also has an air speed of 500km/h, hence a ground speed the same.
But because the second clock is being flown in a direction 180d opposed to the point of origen, the overall flight time will be shorter than it was for the East bound clock. therefore any hypothetical time dilation will be of lesser extent than for the east bound flight. Since 'sence' is missing from the GR equations, if this test had indeed agreed with the theory of GR, the west bound clock would surely have lost some time, but not as much as the 59ns lost by the east bound clock.

You see this so called experiment has introduced direction into the arguement,

Um, not quite correct, actually. Your assuming that the earth bound clock is an absolute frame of reference but relativity doesn't work that way. The west bound clock should gain time according to relativity not because it is moving west, but because its flightline (which just happens to be "west") is counteracting the rotation of the earth. In other words, the west bound clock is decelerating to a slower frame of reference relative to the earth bound clock. Since the earth bound clock is now moving faster than the westbound clock, it time dilates relative to the westbound clock. In other words, the west bound clock should be running faster (ie gaining time) than the earth bound clock.

I remain very much unconvinced of time dilation not only by the appauling lack of statistically compelling data

Hmm, you might want to tell the US Department of Defence, since they did include error correction for time dilation in the global GPS satellite system. Maybe that's why my car has me turning into my neighbours drive .

But wait..........Gravitational lensing?? Now see here, we have sent out interstellar SOHOs to accurately analyse and measure the exact composition and density, refractive index and countless other properties of distant stellar atmospheres. We know to a high degree of accuracy just how much light from a more distant occulted star will be refractd and this just does not account for the observed shift. This clearly proves gravitational lensing, which of course proves beyond reasonable doubt that gravity interacts with light..................I think not.

Gravitational lensing is not refraction caused by light entering a different medium such as the atmospheres stars. It is simply light following a straight line through curved space .... according to General Relativity that is.

BTW, Eric Von Danekin also believes the earth was once visited by aliens. He also features under "Bad Astronomy".

Cheers,
Andrew.

[Starcrazzy]

yep..its the curvature of spacetime...spaceTIME..space and time...time and space....TIME and SPACE...its curved not flat...see...read up dudes...its all there for the learning....check out einsteins ring..http://www.universetoday.com/am/publ...tein_ring.html
there ya have it..a picture of relativity..

[Doug]

Um, wrong actually. Your assuming that the earth bound clock is an absolute frame of reference but relativity doesn't work that way. The west bound clock should gain time according to relativity because its flightline is counteracting the rotation of the earth. In other words, the west bound clock is decelerating to a slower frame of reference relative to the earth bound clock. Since the earth bound clock is now moving faster than the westbound clock, it time dilates relative to the westbound clock. In other words, the west bound clock should be running faster (ie gaining time) than the earth bound clock.

Um, No, I am not assuming the earth bound clock is an absolute frame of reference at all; I thought I carefully avoided that pitfall. perhaps I was a bit vague. But since you raise the point, though the Earth bound clock is not a fixed frame of reference, relative to both air borne clocks it is. The very experemental data declares it to be so, because the data quoted says that one clock lost 59ns, RELATIVE to the ground based clock, and the westward flyer gained 273ns RELATIVE to that same Earth bound clock. The net difference between the two flyers would not be a true relativistic difference, but I suggest that the argument for the westbound time difference is rather hollow because:: for nominally half the flight, both clocks reverse their direction relative to the ground gripper clock. I think you have tried to nullify this point by the consideration of acceleration , but that acceleration is never constant thoughout the test, nor is it even in play for a statistically significant time. Sure from a 3 dimentional consideration things are not so straight forward, but for the sake of reasonable simplicity, let the east bound clock travel east relative to the ground clock, but only till it rounds the Earth. Now as the east bound clock rounds the Earth, still travelling eastward relative to the earth,relative to the ground clock it is in fact travelling westward, until it again rounds the Earth and still travelling Eastward, catches up to the ground clock, so sinse the data is referenced to the ground clock, some of its travel is Eastward but some (nominally half) of its travel relative to the ground clock is infact westward. The same situation exists though in reverse and slightly modified for the Westbound clock. Some of its travel is westward and some of it is eastward relative to the ground based clock. It is not that the Ground based clock is withinn a fixed frame, the data offered is relative to that ground clock forcing upon it the status of a fixed datum point relative to the three clock universe, else why compare the ground clock at all?
After all a net difference of about 330 seconds should be proof enough.........but wait, we can't do that because we need a fixed frame, an absolute against which to measure relatively speaking that is . We need something to measure that is real. How big is the number i? Oh well if relativity doesn't work that way then maybe relativity doesn't really work in the really universe...who can say?

Gravitational lensing is not refraction caused by light entering a different medium such as the atmospheres stars. It is simply light following a straight line through curved space .... according to General Relativity that is.

BTW, Eric Von Danekin also believes the earth was once visited by aliens. He also features under "Bad Astronomy".

Hmmm I'll have to use simpler language I think.
The evidence for GL as I have read it was the measured shift in position of a close grazing or even occulted star as its light passed close to a large mass (a nearer star) This was the 'proof' of Gl that I first read of. This was the observation that I believe first gave GL its name. Since very little is known with any certainty about conditions close to distant stars, I consider it whistful thinking to claim proof of something when so little is really known or understood about the conditions prevailing. My reference to Eric Von was simply to point out the absolute ridiculousness of siezing on small values and claiming them as proof of something as Eric Von did, as many current researchers are still doing. In othere words, my thumb when multiplied by a suitable number would yield 93 million miles too; so what? That was the sort of nonesense Eric Von used to validate some of his myth. I was not holding Eric Von up as any sort of credible researcher.

Even the leading cosmologists can't agree on things relativistic. That should tell us something. They range from 'it was true along time ago in a galaxy far, far away', to 'it is only true for the first picosecond after the big bang..', to 'it isn't right now but it might be one day'. But of course openly refuting Einstein could see many a science world vendetta being issued against those scienific infidels.

But all this is not getting my pier poured.

I'm not saying Time dilation doesn't exist, I',m saying there is as yet no statistically compelling data that I am aware of to support the notion. Sending a clock across the solar system intercepting it six months after launch might tip the balance one way or the other, because gravitational influences and acceleration differentials would be a statistically small part of the overall time and velocity involved.

[AGarvin]

Whatever ... this will go around and around for ever and I have to say I'm over it.

Let's agree to disagree.

[Shawn]

Agreed

[xelasnave]

When one day a space craft returns from "deep space" and there are a few headed out there ..which will return someday..when we get one back we can "date" materials on board and see if the effect is real or imagined. I have done no work on the experiment or have I read the Doctors book again as I said I would.. been working on other stuff though. But it seems all have been worn out by the exercise but have we not some wonderful thinkers to engage these issues. But in respect of my example of the ships nothing alters if you reduce the speeds or the distances the effect I decribe is present. I will do more when I can turn up one of the Dr's mind exercises and see if I can see it different.
alex

[g__day (Matthew)]

Time diliation is one of Einsteins more profund insights and thought experiements. It was so radical at the time he didn't get his Nobel prize for it but for photoelectric effect showing light can exhibit the properties of both a wave and a particle (at the same time!). Time diliation took decades more to start proving experimentally and prove it we certainly do every day.

In the air plane example its altitude reached (effecting gravity) and whether you are travel with or against the Earths movement in space around the Sun that causes the variance between the clocks.

Global positioning satellites have to correct for time dialition every day (increased distance from Earth lessens gravity speeding its time relative to us whilst their up to 30km/sec ortibal velocity slows time relative to us (but these time diliations are unequal in magintude causing a net need to correct about 25 microseconds a day)). Without correction we lose about 10 yards per day in accuracy!

Atomic colliders see great evidence of time dialiation. CERN often produces collisons that produce exotic particles that have very short lives before they decay - between 1 to 0.1 millionith of a second. Yet these particles can exist relative to us for up to 1000 times longer - almost milliseconds when they are travelling at 99.98% of lightspeed due to time diliation.

There is now a vast amount of supporting evidence of time diliation, its one of Einstein's best proved theories.

Relativity shows us that our frame of reference is critical to our sense of reality. There is no absolute time. It changes as you move, it changes if you are close or further away from a heavy mass. Relativity shows us that energy and matter are equivalent, not just convertable but equivalent. Meaning they are two directly linked attributes of a deeper underlying reality; like each is just one face of a coin or a dice we can interact with. Relativity links time and space with matter or energy in it. Space tells matter how to move and matter tells space how to curve. Gravity is not a force, it is the curvature or the underlying topology of spacetime itself.