madmac

swansont. I think the answer in my special case of identical opposite free-fall (inertial) orbits is that the twin's 2 pix would show equal times (eg 9:00 & 9:00 in both pix), ie showing zero relative time dilation. Whereas i think that the/a previous answer was that the 2 pix (for the case of the original OP) would show equal relative time dilations. Although, it seems to me that this wordage is ambiguous. It could mean that the 2 pix showed identical times for both clocks (ie say tower-clock=9:01 & plane-clock=9:00 in both pix) -- or it could mean that the 2 pix showed different times but equal dilations (ie tower-clock=9:01 & plane-clock=9:00 taken by tower-twin, & tower-clock=9:00 & plane-clock=9:01 taken by plane-twin). I am thinking that my answer in my special case might be ok, & different answers in other cases might also be ok, the (perhaps only) problem being that the original OP wrongly (i think) insinuated that only one correct answer was possible (in accordance with SR & GR).

I don't understand much of these explanations. How about this special case of the OP. The tower-twin is on Earth's equator & the tower is so hi that he is in circular free orbit. The plane-twin is also in circular free orbit, "flying" the other way. This setup fits inside the OP -- but the answer is not the same as any given here to date. Why??? A slight difference to the OP. In my special case the pix could not be dropped to the tower base -- if dropped they would collect at the tower top (ok i think).

I like this thought experiment. DanMP mentions only 2 or 3 or 4 possible results (not sure which). But i see a total of 9 simple possible results (am i correct).

I thought that Einstein belatedly invoked the moving twin's acceleration-deceleration-(turnabout)-acceleration-deceleration as being the key to explaining why the paradox wasn't a paradox at all. But those links above dismiss the need to invoke any acceleration (& deceleration). I guess that the above links dismiss acceleration (& deceleration) to counter the more modern example of the paradox (this might be the third twin referred to). If i remember aright the modern form uses a third clock C (heading towards the stationary twin-clock A) which passes the outgoing twin-clock B, & the 2 clocks C & B instantly synchronise (thusly eliminating the deceleration-acceleration at the turn point). Perhaps they also eliminate the initial acceleration by having twin B already moving when A & B first meet (at the start), & then eliminate the deceleration at the end by simply comparing clocks C & A as they pass. I would be surprised if the above links satisfactorily explain that the paradox doesn't exist (without invoking acceleration). Einstein had to invoke acceleration.

Censorship makes sense -- this (relativity) forum mainly sticks to mainstream, ie Einsteinian stuff -- & there are anti-relativity forums out there that likewise tend to censor pro-Einsteinian stuff. Arguing re who is correct might be ok in theory, but does little good, a 90% waste of time -- i reckon that not one argumentator changes his-her philosophy in a years worth of arguments. Perhaps one or two disinterested persons (readers) change their mind. U learn lots here -- lots of links to scientists & papers etc that u have never heard of. Re lying to the public -- i think it is mainly a case of scientists lying to themselfs & themselves. Someone said that science changes one funeral at a time. I aint that optimistic. Einsteinians own the universities, & the money & the Nobels. However, us aetherists have one thing on our side -- ultra accurate clocks -- these will prove STR & GTR wrong in every instance. And Einsteinians cant wave away the results for ever.

A general observation. Surely we all agree that there is no such thing as time dilation -- it is merely a change or difference in ticking. I think that Einstein goes one step further -- i think he says there is no such thing as time -- hencely no such thing as time dilation. Surely we all agree that time passes at the same rate for all, all the time. We all sense that our inner clocks tick at the same rate, all the time, no matter what is happening to our wrist watches. If u whirl your wristwatch around & around (in the vert plane say), Einsteinians would say that it ticks slower. But time must surely seem to pass at the same rate for all of us, no matter whether our watch is good or slow or fast, no matter whether we whirl our arms (with the wristwatch), no matter which twin we are. But getting back to JohnLesser's OP. Would it be true that the present only exists locally because of the nature of light and its finite speed only allowing delayed images of observation? I reckon that this question could be well debated by a deaf person (or not deaf) & a blind person. Also, imagine how our world would look (& the effect on the present) if sound travelled at c, & light travelled at Mach1.

An observer & a hearer & a feeler go into a bar, & they ask the barman (a smeller) -- Hey, whats the time?????? The barman, can smell a ticking clock's ticking -- the observer can see the hands moving (this was many years ago) -- the hearer can hear the ticking -- the feeler feels the ticking. The guy playing pool, who is a taster, says -- Its sweet'o'clock. Who was correct. Well, on this forum Einstein is always correct. Luckily for this forum Einstein could see. If he couldn't see but could hear then E=mcc would be something else, but still wrong. According to Einstein if it were not for light, we wouldn't have time at all. And no length contraction, no time dilation. No present. No clocks. And no trains. But seriously, if light had infinite speed we would still have time & we would still have the present. What we wouldn't have is STR & GTR. But, hey, we don't have STR & GTR today, locally, at present, ie when light duznt have infinite speed, but don't tell.

zztop. Thanx very much for that, I also found a free read only copy on MyJSTOR of a book by Roberto Lalli -- Anti-Relativity In Action: The Scientific Activity of Herbert E Ives between 1937 and 1953. Which looks to answer my other wish re history papers in the wake of the experiment. These will take me a few days to digest. Thanx again.

zztop. Thales et al had trouble finding original info on Ives & Stilwell. So did i. Wiki stuff is Einsteinian propaganda, & heavily censored. If Ives & Stilwell were fully anointed & baptised apostles of Einstein, & if their experiment was a heavenly example of the truth of the SR, then why cant we find any of the original Gospel according to Ives & Stilwell? All we see is propaganda. Einsteinians have even used Ives & Stilwell to "prove" Einstein's transverse Doppler. I would love to see some or all of Ives & Stilwell's original paper. What was their intention -- theory & equations -- test results (in full) -- conclusions (as Thales et al says -- what were their claims). Also, any info on Ives or Stilwell in the wake of their experiment. Any history re papers leading up to or following the experiment, & how it all influenced their professional lives. If u google wiki for -- Herbert E Ives -- u will see some breathtakingly disgusting Einsteinian propaganda twisting Ives' beliefs.

Thales et al asks -- what is being claimed in this experiment.(???) TIME AND THE METAPHYSICS OF RELATIVITY -- WILLIAM LANE CRAIG -- 2001. Craig says.......... ...............Ives & Stilwell were themselves neo-Lorentzians & so interpreted their results as a vindication of clock retardation for inertial frames in motion relative to the aether frame. "The conclusion drawn from these experiments is that the change of frequency of a moving light source predicted by the Larmor-Lorentz theory is verified," they concluded. Einsteinian relativists point out, however, that the results can be equally interpreted as a verification of the Einsteinian interpretation of Special Relativity.......... Prof Reg Cahill shows that Ives & Stilwell were correct -- Einsteinians wrong -- the results do not equally verify Einstein. Simply google -- cahill ives stilwell. A wonderful paper by perhaps the most important scientist alive.

Perhaps a big clock feels time differently to a small clock, even though they tick at the same rate.

Time passes at the same rate for every person. Your watch ticks at the same rate, all the time (pun intended). This has to be so, if time dilation is true, & if not true. But the ticking of an animal's or insect's inner clock is probably a function of the distance tween eye & tickerthalamus & brain. This might be a direct proportion (D), or it might be related to D^2, or perhaps D^3 (ie proportional to mass). One year to an ant might seem like 100 of our years, or 10,000 years, or based on mass 1,000,000 years. I reckon 100 years. One year to a whale might feel like a few months to us. But anyhow i reckon that time passes at the same rate for every person & other animals & insects. But if it don't have a brain, then u don't have a memory, & u don't have any awareness of time. Do bacteria feel time?? Do trees feel time?? Re imaginary time, all time is imaginary. Time doesn't exist, it is an illusion.

SFNQuestions -- post#1. Like if i have a parabola of velocity versus time or position versus time, is there any physical meaning to the arc length of that function? I can see some physical meanings, re a parabola. Firstly it is impossible to have a parabola of vel versus time. A parabola has infinite length, but vel is limited to c. However it is possible (even in an exclusively Einsteinian forum such as this forum) to have a need for a velocity quantity of up to 2c. I suppose that the sum of the velocities of a number of objects can be much greater than c, but this would still be finite. The torchlight-effect can give great speed, but perhaps not infinite. But, even if infinite, it still wont give u a parabola, because a parabola here also needs an infinite time (on the time axis), in fact it needs two infinite times, one going back to the start of the measurements, & one going forward to the end. Ignoring here that perhaps it is possible to construct a graph where the parabola is leaning such that it is asymptotic to the velocity at one end, but even here the other end will need an infinite time. On this forum an infinite time is impossible in either direction. Firstly, going back in time, time started with the BigBang -- no infinity here. And fast-forwarding a bit, there might be a time when our universe ceases to exist, in which case there will be no infinite time in that direction. And even if time does go on forever, we will not be able to draw our parabola until time stops, in which case it wont be a parabola anyhow, it will be a part of a parabola, ie parabolic, but not a parabola. A parabola of position versus time is simpler, but still impossible. Position means distance. Unlike velocity or speed, distance is not limited by the speed of light c. But a graph of a parabola still suffers from problems re time (see above). But even if u could draw a parabola describing vel or position versus time, there wont be much physical meaning to the arc length of that function. Firstly the arc length would be infinite. All such arc lengths would be infinite. Hencely the analysis might boil down to what is the meaning of infinity. If we change the question to relate to parabolic curves then that might be more meaningful (re arc length of the function), but still not good. Here i suppose that the meaning is arc length per unit time. The total arc length depends on when or where u decided to start & finish, not much scope for any interesting meaning here. The arc length per unit time of any small part of the parabolic curve seems to me to have no interesting ponderable meaning. The function of the change in this small arc length will i suppose have a simple equation, which i suppose will have no interesting ponderable meaning. If the parabolic curve has an axis of symmetry then i suppose that the arc lengths on one side will have mirror images on the other, no big deal. Unless the axis of symmetry isn't vertical, in which case u wont. Which leaves me with only one more physical meaning that i can think of. Arc lengths never reach the vertical, & therefore never reverse (turnabout)(return) back along the time axis. This means that (real) time cannot physically go backwards. I think that this means that time is mathematically a scalar not a vector.

Pugdaddy. So, gravity might be (1) an excitation of the space-time field that (2) disturbs the space-time field, which (3) then changes the geometry of the space-time field, which (4) then affects other how other types of excitation in the space-time field move. I think that (1)(2)(3)(4) are indeed in effect mainstream Einsteinian gravity. Except that i think that (4) should not refer to other types of excitation, it should refer back to the original (1) excitation. But if the meaning of (4) is not other types, but the same type but other occurrences, then i wonder why if it affects other occurrences does it not affect the originating occurrence.

Pugdaddy. Particles being pieces of spacetime sounds like aether to me. Particles in spacetime aint aether. I had a quick look at the article. I like much of the theory of particles & waves. Some of it smells like aether theory. It mentions dipole waves in spacetime. It says that the spacetime field is the stiffest possible medium. It calls gravity a force at least once.

Religion & old gods were modern science in the oldendays. Nowadays science has new gods, new dogma. Its funny that most of us atheists around here are not aetherists. But i suppose that some aetherists believe in God. I thought that Newton created the word gravity, but perhaps he only invented its re-use (an earlier post said he didn't create the word). An earlier post said that gravity is more sensible today (obviously referring to Einsteinian bending of space-time)(a joke). An earlier post suggested that heavier things didn't fall faster. But surely a small object with the same mass as Earth would fall at 2g if next to Earth. But in a sense that post was correct -- if u drop objects they fall at the same rate, eg that-there small object & a feather would fall to Earth at the same rate (in vacuum). Technically, while falling to Earth, the feather would also fall to the small object faster than the small object falls to the feather (just thinking out loud). This thread about gods (or the definition of gods)(or something) is mosty silly, yet it touches important (science) issues.

Today i read -- Searching for the Ether -- 2011 -- DIO 17 -- The International Journal of Scientific History. In Section K7 (page 25) -- Local Comparison Between Pendulum Clocks and Chronometer -- it mentions Courvoisier's experiment. In Section H1 on page 19 -- it mentions another experiment where Courvoisier supposed that Lorentz contraction changed the shape & radius & local vertical of the Earth periodically with sidereal time. This is slightly relevant to my post#33 where i mentioned the possible use of a pendulum clock together with a balance clock to determine changes in big G, & i said that i didn't read it anywhere. Well now i have (although for a different experiment). And it is slightly relevant to post#18 by Strange where he says -- .................. it is entirely possible that the radius &/or mass of the Earth varies when G changes in order to keep pendulums swinging at the same rate. I will have to have a think about all of this, ie whether Lorentz contraction changes Earth's radius & the local vertical, & hencely measurements of g, & hencely some types of measurements of big G. It would affect pendulum tests, & drop tests (gravity tests), but wouldn't affect torsion-wire tests (inertia tests). But in these sorts of cases every local thing is surely contracted too, ie the standard meter, the shape of the observer, the shape of the observer's eye, & to some extent we might have a change in time dilation. I cant think of any Einsteinian answers, ie using SR & GR. Perhaps a bit of time dilation. Change in mass??????

swansont re your post#7. I am very interested in time dilation related to spinning objects (eg centrifuge), ie due to mass. This makes good sense to me. Actually this is a pet area of mine. Have u (or someone else here) a link or something i can google. In the past i found a few vague reports by Podkletnov (a crank), & DePalma who was a crank (deceased). I found stuff on transverse Doppler, which is similar (but perhaps not exactly what i am looking for), but i would be interested in any such link anyhow.

swansont in post#17 said.... When a mass undergoes acceleration (of certain types), it causes gravity to change. These changes propagate at c. I would like to add. We mostly talk of macro-mass -- but i daresay that it is actually the smallest particles having mass (micro-mass) that do the trick, & the contribution of each micro-field adds (or negates) to give a nett-field (which we attribute to macro-mass). And the smallest particles might be photons or quarks or muons or something (not important here). This is my idea of mainstream theory. So, we come to acceleration. The acceleration of micro-mass creates a micro-field (gravity)(bending or unbending of space-time). Micro-mass doesn't know whether it is contributing or negating when it radiates (due to acceleration). Hencely, a quadrupolar gravitational wave is just the nett effect. Hencely a spinning non-quadrupolar body radiates no less than a spinning or orbiting quadrupolar body, but has zero nett effect on gravity (at least at large distance). Hencely a spinning sphere (say) must lose mass etc too, even though it doesn't affect nett-gravity (ie makes no nett gravitational wave). This is my idea of mainstream theory. Am i wrong?? Re acceleration of certain types. When a micro-mass is accelerating it doesn't know whether it is linear or centrifugal. And all such acceleration of all micro-mass all causes gravity to change all the time (propagating at c), & if there is a nett overall change then we have a change in gravity, called a gravitational wave. And, it isn't a wave, it is a pulse (made of lots of micro-pulses). This is my idea of mainstream theory.

mistermack. I think that there are 2 classes of clock -- inertial, & other. Other would include pendulums & hour-glasses. These would read zero when in free-fall, & that-there zero would not be affected by time dilation. And, an inertial clock would tell me my age exact at all times, if i wore it on my wrist (& didn't do any hand waving). Time dilation wouldn't affect it from my point of view -- ie time dilation would affect me & clock equally. After all, there is no such thing as time, or, putting it another way, time is relative, which we all know i guess.

swansont. Re How would u get the quadrupole radiation of GWs from mass conversion?. I suppose that a quadrupole GW is a pulse, lots of single pulses (not really a common wave). Spreading in all directions, but moreso in one direction (lighthouse effect). And if a bit of mass suddenly appears somewhere, then we have a sudden single pulse (attraction). And if a bit of mass suddenly disappears somewhere then we have a sudden lessening of gravity (a single negative pulse). Spreading equally in all directions. So its the same thing only different. If indeed there is such a thing as creation & annihilation of mass nowadays. Lord Antares re post#1. U said... ... So all of the gravity there is already in effect. There can be no "speed of gravity". Yes this is the mainstream theory as i remember it. This appears ok if the Sun is considered fixed, & the Earth moves through the Sun's space-time field, then the Earth feels the Sun's gravity "instantly" at all times, even though the field itself is limited to speed c. But then also the Sun must consider itself to be moving through the field of a fixed Earth, to feel Earth's gravity instantly at all times. And likewise the Sun & every body in the solar system must be considered fixed & yet not fixed for this "instant" theory to work. Or am i wrong??

swansont. I think my comment re mass isnt changing is referring to Lord Antares post#4 where he says that a mass couldn't appear out of nowhere. This probably referred to the macro world -- but i think my comment included macro & quantum worlds. Anyhow the question is whether nowadays there is ever any loss of mass or creation of mass of the kind that would give rise to a gravitational wave (travelling at c). I guess that in other words this asks whether there is a change in the number of real particles having real mass (or a change in total mass). And i guess that here radiation doesn't have mass of the type giving rise to GWs.

Sensei, Strange, Lord Antares & co. It looks like i have been accused of hijacking, but one would think that the speed of gravity was not irrelevant to infinite plates. However the speed of gravity is one of the most important issues ever (albeit ignored i think), & deserves its own thread. Mainstream says that the velocity of the gravity effects of any changes in mass travel at speed c by virtue of gravitational waves. Likewise quadrupole rotation & spin effects. And mainstream says that any non-changes in mass act instantaneously (or in effect instantaneously), including for moving mass. Although only locally. Hencely Earth feels the gravity of the Sun at the Sun's true position -- but feels the loss of gravity due to any loss of mass in the Sun at velocity c, ie at the Sun's visible position. Or am i wrong?? And i am surprised that it has been said that mass isn't changing. I thought that mass was lost in nuclear explosions (fission & fusion). And that perhaps mass is created also, i mean real mass (somehow somewhere). Or does mainstream consider that (nowadays) mass in effect only changes form (mass to energy)(& vice versa)?? In all such cases the speed of the change in gravity would be c. But perhaps the mainstream idea is that a change from one form to another results in no (nett) gravitational wave. Or am i wrong??

edit -- speed of gravity is now on new split off thread.

Strange. Einstein doesn't need a true c. And, he has an infinite number of possible c's, or at least only limited by the number of observers. And Einsteinians obviously get goodish answers lots of the time. If there is a true c (ie only one truly stationary frame) then SR & GR cannot be correct (as he knew), or not 100% correct, or only correct in certain instances (whatever). We hear of lots of things that prove Einstein correct, forgetting that there is no limit to the number of theories that can accord with any experimental result. Tim88. Yes, i see that in the intro they don't use the word determined nor the word measured. Although i notice that in Section 2 the wording of the postulate (called principle at this stage) is similar or identical to the wording i mentioned earlier, ie using the word determined. I see that the intro also says -- "The introduction of a "luminiferous ether" will prove to be superfluous....... " -- which accords with the statement i often make that Einstein didn't rule out an aether, he merely made it redundant. Which sort of resonates with my above comments to Strange. Tim88. U say..... A wave has a certain or constant speed c ...... This reminds me that i need to start a new thread in Speculations. Your statement depends on the definition of a wave. I already knew of the problem (that i thought of, i didn't read it anywhere), but it surfaced again (i say again because i first saw it when i read Hicks' calibration of M&M)(1905) when i read an article using one of your links (or someone else's here), where it said that Einstein took Newton's 0.87 arcsec to 1.75 arcsec mainly by using the bending of light (as it passed the Sun) by virtue of redshift. But i wont go into it now. I am just flagging that your seemingly simple wave statement (& Einstein's redshift methodology) might not be so simple. And this has nothing to do with aether.