Ether & the Hafele-Keating Experiment

I haven't read this thread completely, but I think these comments might help:

(1) The reason you can't detect any effect of the aether on the speed of light is this: Any clock made of atoms and/or light waves, which might be used to measure the speed of light, is affected by the aether in exactly the same way that the speed of light is affected by the aether. Even the motion of electrons around nuclei is affected the same way that the speed of light is affected. Therefore, we can neither prove nor disprove the existence of the aether--except, perhaps, by Aristotelian philosopical arguments. This is why MM turned out to be a null experiment; it proved nothing. Repeating it with spacecraft, at any speed, is pointless.

(2) SR isn't proven wrong by experiments; it just isn't any more applicable to any real experiment than it is to the so-called Twins Paradox. When Einstein introduced the "paradox", I'm sure he had his tongue firmly planted in his cheek, as it came at the end of a lecture on SR. He had repeatedly said SR is applicable only to the special case in which there is no gravity and no acceleration. So please explain to me how one twin can complete a round trip without experiencing gravity or acceleration? Funny old Alf wasn't mistaken; it was just his idea of humor. Such a pitty that no one got the joke!

If you apply GR to the problem, the twin who accelerates (relative to inertial coordinate systems) ages less than the one who remains home, regardless of which twin is the observer; so there is no paradox. Likewise, a clock in Earth orbit should run more slowly because it experiences slightly more acceleration than a clock on the North Pole. That's because a zig-zag path around the sun is longer than a smooth ellipse.

(3) As for the speed of a planet in a circular orbit around the sun: The GR equations relate to velocity, not speed (though most scientists carelessly use the terms interchangeably). The difference is: Speed is a scalar quantity. Velocity is a vector, having both speed and direction. The radial component of velocity of the planet is zero; so the planet's speed is zero--in a coordinate system which rotates with the planet around the sun. This is not an inertial coordinate system. If you feel like transforming the GR equations into a rotating coordinate system, be my guest. In a heliocentric inertial rectilinear coordinate system, the planet's speed is equal to the tangential component of its orbital velocity.

(4) If the aether exists and is dragged along by the Earth, then it might be possible to measure the effect. As far as I know, no such effect has been detected. I suspect that the aether does exist, but is not perceptibly dragged by matter whose density is as low as the Earth. After all, the Earth is practically 100% empty space, since the nucleus of an atom is so much smaller than the cloud of electrons around it. Perhaps the core of a neutron star is sufficiently dense to drag the aether, but, for all we know, neutrons may be composed of particles many times smaller than the space that contains them; even a neutron star may be vitually empty space.

The aether may be composed of particles so tiny that most of them can pass thru a neutron star without being affected. We have yet to demonstrate any upper limit on the strength of gravity, or any case where gravity is not proportional to inertia--presumeably because most CG's pass unaffected thru celestial bodies. If the particles that compose the aether are anything like CG's, the same may be true of them. Therefore, it is unlikely that the aether is dragged along by a puny vapid planet like the Earth.

I have read the coments above(page1)and question atomic clocks?Are you blokes refering to light clocks or atomic clocks?(relatively speaking,an atomic clock is not all that fast.)

proton

Both atomic clocks and light clocks are made of atoms and/or light waves. I can't conceive of any clock that isn't.

For my explanation of light clocks, see my post from a few minutes ago at Details of Light Waves .

I can't speak for the others, but I believe an atomic clock relies on the uniform decay of particular isotopes. Given a known mass of a particular isotope, a certain number of nucleii (plus or minus a perfectly random variation) will decay each second, slowing at a rate equal to the half-life of the isotope. We don't know enough about the internal workings of nucleii to explain why, but experimental evidence indicates that atomic clocks obey relativity the same as light clocks.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">...relatively speaking,an atomic clock is not all that fast...<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">I assume you mean that it can't measure short time intervals; not so. If the number of nuclear decays per second is sufficiently large, then the random variation will be an insignificantly small fraction. If you have only a few decays per microsecond, then you can't rely on microsecond precision, but for longer intervals the clock is extremely accurate. With a sufficiently large sample of the isotope, you can get nanosecond precision---just make sure you are well shielded to protect your health. Anyway, I don't think the H-K experiment depends on measuring short time intervals.

If you have an unknown mix of isotopes, you can still calibrate the clock and get extremely accurate results---provided you don't have a significant portion of short half-life isopopes in the mix.

PhilJ,

Atomic clocks do not rely on radioactivity. They use the light emitted from excited atoms. Sort of like what a laser does, but different. Anyone can buy/build one (parts from Hewlitt Packard for example) for a few thousand dollars. Comes with a steep learning curve at no extra charge. No radiation.

Wikipedia has a decent discussion. Or just Google on "atomic clock".

LB

<center><font size="4">[] Boy, Larry! Am I behind the times, or what?! []</font id="size4"></center>

I could have sworn there was something called an atomic clock which worked as I described. But, according to How Stuff Works , the Cesium Atomic Clock, which works as you described, dates back to when I was in first grade. I, or one of my teachers, must have confused it with radio carbon dating a long time ago and no one set me straight until now. Thanks, Larry.

Nevertheless, I don’t understand why Proton says, “an atomic clock is not all that fast.” The Cesium Atomic Clock resolves time to just over a tenth of a nanosecond. Isn't that good enough to detect the .7 ns siderial fluctuation mentioned by wisp in post #1 above?