Morley/Michelson Inferometer

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />The spin of the Earth around its axis is different than the spin of the Earth around the sun?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Those two motions have nothing in common. For spin (rotation), the Earth could be standing still or moving. Either way, people at Earth's poles see the same stars overhead, while people at Earth's equator see the stars rise and set daily. It is a motion like a spinning top.

Earth's orbital motion is not a type of "spin". It is called "revolution", as contrasted with "rotation". It is like a linear forward motion of the entire planet, except that the path is gently curved by the Sun's gravity. It causes no change in star positions (neglecting tiny effects such as parallax and aberration), but does cause the Sun to appear to move through the constellations of the zodiac in a yearly cycle.

Get a copy of "The Stars" by H.A. Rey. The second half of the book is the best I've seen for getting a quick understanding of the celestial sphere and the various motions that affect it.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">And why is the light carrying medium moving at the same rate and direction as Earth in the first place?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

The light-carrying medium is affected by gravity, just as everything else is. So like Earth's atmosphere, nearby parts of the medium are captured and entrained by the Earth. Far away parts are not affected by Earth. That is why every local gravity field becomes a "preferred frame" near that body. -|Tom|-

The answer provided by SR is that time dilates and length contracts in such a way that the speed of light is unchanged by the inertial motion of the observer.

This is the key point. Does time really dilate? Does lenght contract? These are contradictory conclusions. How does the length contract in the moving frame? This doesn't make sense at all. SR says that it appears contracted to an observer at rest in the moving frame. But, if this is true, it is an actual contraction and can only be a prediction of the Lorentz theory of relativity. The same is true for time dilation. In SR the dilation is what is seen by an observer at rest in a moving frame. But this says that the time actually dilates. I find this interpretation confusing. Yet, this is apparently what most textbooks claim to be true.

I think that the Michaelson-Morley experiment really doesn't support Einstein relativity at all. It is an ad hoc explaination. Can someone show me the proof that it really proves the correctness of SR? I am waiting. Show it to me. I think the experiment really proves Lorentz relativity with an absolute frame defined by the earth.

I think we need to clarify terms. Spin is not the correct word. The earth rotates on its axis and it revolves around the sun. Spin is not defined in this context. The sun rotates, as do planets, on thier axes. Planets revolve around the sun. If you keep to this terminology it helps.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by kc3mx</i>
<br />How does the length contract in the moving frame? This doesn't make sense at all. SR says that it appears contracted to an observer at rest in the moving frame. But, if this is true, it is an actual contraction and can only be a prediction of the Lorentz theory of relativity.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

My article "Lorentz Contraction" in the 2003 September 15 <i>Meta Research Bulletin</i> explains this phenomenon for both SR and LR. -|Tom|-

Spin, rotation and revolving are more about the location of the observer is what all of you seem to be eluding to and if that is correct then I agree that they are or seem to be different. If the observer is at a different location the rotation would be spin-at least that seems to me to be the case. The pole of Earth is to the equator as the sun is to the eclipitic of the solar system. The point is motion is motion and not special to a frame of reference.

I think that it is misleading to refer to Lorentzian relativity. When this is used I think it is confusing to people who have conditioned to think relativity means the Einstein version of it. The real problem is that there are all kinds of theories that can be called relativity. These are not all the same nor do they all assume the same things. Lorentzian relativity seems to be based on the idea that an absolute reference frame is needed to derive the Lorentz transform. Einstein relativity is based on the speed of light being constant for all observers and that there is no absolute rest frame.