Relativity question

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by rush</i>
<br />If motion is always relative to some ‘arbitrary’ frame of reference, can I claim that, although it may be more convenient to assume that the earth orbits the sun, it is also correct to say that the sun orbits the earth in spite of all evidence to the former??<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Only linear motion is relative. Acceleration is absolute, and can be immediately detected by watching for changes in the doppler shifts of all stars.

Astronomers frequently adopt an Earth-centered frame of reference, in which the Sun orbits the Earth. It can be very convenient when using Earth-based observations. However, we can be sure that reality is that the Earth orbits the Sun and not vice versa because of shifts in the positions of nearby stars due to parallax, shifts in the positions of all stars due to aberration, doppler shifts, changes in the arrival times of pulsar signals, and other similar data. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>
Only linear motion is relative.
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In reality, it is very hard to imagine a truly linear motion isn't it?

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
Acceleration is absolute, and can be immediately detected by watching for changes in the doppler shifts of all stars.
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Right.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
Astronomers frequently adopt an Earth-centered frame of reference, in which the Sun orbits the Earth. It can be very convenient when using Earth-based observations. However, we can be sure that reality is that the Earth orbits the Sun and not vice versa because of shifts in the positions of nearby stars due to parallax, shifts in the positions of all stars due to aberration, doppler shifts, changes in the arrival times of pulsar signals, and other similar data. -|Tom|-
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Can I use this as an arguement in favor of Lorentz Relativity? Or the only arguement is that the Earth's is a fixed reference frame in the GPS system?

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by rush</i>
<br />In reality, it is very hard to imagine a truly linear motion isn't it?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Not at all. "Linear" in this context is the equivalent of "inertial", which means simply "no forces acting". Lots of motion occurs in the presence of only negligible forces.

Moreover, even accelerated motion such as Earth's orbital motion can be approximated as a series of linear segments. That is how special relativity manages to work for accelerated systems. "Lorentz boosts" are used to convert accelerated motion into a series of linear motion segments interspersed with tiny, instantaneous velocity changes. The number of such segments may approach infinity, if needed, so that the linear approximation can always be made valid for practical purposes.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Can I use this as an argument in favor of Lorentz Relativity? Or the only argument is that the Earth's is a fixed reference frame in the GPS system?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Lorentx boosts allow SR to handle all cases of accelerated motion. While much experimental evidence has a simpler explanation in LR, the <i>only</i> experimental evidence intolerable to SR is the existence of FTL propagation in forward time in the form of experiments showing that the speeds of gravity and Coulomb force greatly exceed the speed of light. -|Tom|-

Ok Tom, I got another question...

I'm trying to understand exactly how LR can replace ER. Up to now, it seems to me that LR can really explain all experiments that are explained in the context of ER, but not without assuming that the Earth is a preferred reference frame (static in relation to the ether)... A friend of mine pointed out that the ether also should had "contradictory properties of elasticity and wave propagation" which would be related to the ether "drag" hypothesis. Can you explain the latter to me?

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by rush</i>
<br />it seems to me that LR can really explain all experiments that are explained in the context of ER, but not without assuming that the Earth is a preferred reference frame (static in relation to the ether).<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">You are confusing Lorentzian relativity (LR) as developed during the past decade with the Lorentz Ether Theory (LET) of 1904. LET assumed the existence of a universal ether, whereas LR adopts the local gravitational potential field as the local preferred frame. In LR, there is no universal preferred frame, so the Earth's preferred frame is not in any way special except to Earth residents. And the Earth-centered inertial frame is most definitely <i>not</i> static in relation to elysium. Part of the reason for the name change (ether --&gt; elysium) is to emphasize that elysium, unlike ether, has no preferred universal frame. Local observers are in the situation of a microbe in Jupiter's atmosphere trying to decide which wind current is more "universal" than any of the others when all have some unique peculiar motion.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">the ether ... had "contradictory properties of elasticity and wave propagation" which would be related to the ether "drag" hypothesis. Can you explain the latter to me?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">These were problems for ether theory that have no counterparts in elysium. Ether had those properties because quantum particles are the smallest substantive things (in standard models) and have a minimum size, so anything moving through a contiguous medium of quantum particles must necessarily experience substantial drag and lose momentum to the ether.

Elysium has no such drag because it is composed of "elysons", which are orders of magnitude smaller than quantum particles and are too small to be very interactive with ordinary matter through collisions. Instead, graviton shadows near masses produce density gradients in local elysium by squeezing the medium from gravitational pressure.

Bulk displacement of elysium does not generate light waves any more than bulk displacement of air produces sound waves or water flowing through a pipe produces water waves. So the fact that elysium flows rapidly past the Earth has no major consequences for the speed of light waves, as Fresnel drag experiments showed. (Light speed is not strongly influenced by motion of the medium it propagates in.) Instead, light waves are waves of changing pressure (density) in elysium, and are independent of how any particular elyson or group of elysons is moving. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>
You are confusing Lorentzian relativity (LR) as developed during the past decade with the Lorentz Ether Theory (LET) of 1904.
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Do you have any reference about Lorentzian Relativity like in a peer-revewed journal?

Have you tried to publish the theory of elysium?

Another question that I have is concerned with the constancy of the speed of light. According to Einstein's definition of simultaneity, the one-way speed of light can't be measured and it is defined as the constant c. It was told to me that some experiment carried out in 1964 was designed to measure the one-way speed of light, through the emission of gamma rays during the decay of pions. They got c. It was also proved that when the pions were moving , the result was also c. But if light cannot be measured in a one-way travel (because that would depend upon the definition of simultaneity) how can they say that the experiment proved the second postulate of Einstein's relativity? How they managed to get the clocks synchronized in that experiment?