Aberration of Starlight

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Thomas</i>
<br />Can anybody give me some references for original publications of modern observational data for the 'Aberration of Starlight'? I would be particularly interested in observations obtained in the radio region of the electromagnetic spectrum. I have searched Google for this but could not find anything. It appears that everything regarding the aberration of starlight rests on Bradley's observations from 300 years ago.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Bradley discovered the phenomenon and many papers appeared to confirm that discovery. Since then, it has not been news, so few people write anything observational about aberration.

The theory is written up in the "Explanatory Supplement to the Astronomical Almanac". (I recommend the 1960 edition over the 1991 edition, but the latter does deal with all wavelengths whereas the former concentrates on optical wavelengths. But be prepared for more technical discussion and more math in the later edition.) This does not discuss observations because every astronomical observation made every day that involves an absolute position requires applying the very successful theory to derive that position. This includes transit circles, radio telescopes, and spacecraft. Without those corrections, the positions of objects would describe ellipses on the sky that reflect Earth's motion around the Sun. -|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>
The theory is written up in the "Explanatory Supplement to the Astronomical Almanac<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote"> Theory? I thought the theory for the Aberration of Starlight is assumed to be given by the Lorentz transformation. The point is that, as shown on my page www.physicsmyths.org.uk/aberration.htm , the Lorentz transformation should actually not result in a change of star positions but merely in a rotation of the star. With my own interpretation regarding the invariance of the speed of light (see www.physicsmyths.org.uk/lightspeed.htm ) there would not be an aberration either as everything is completely independent of any velocities.

As far as I can see, the aberration necessarily implies a preferred reference frame i.e. an 'ether' (and with this effectively a frame dependent speed of light). But as this 'ether' must be some kind of physical substance (in order to avoid logical ambiguities regarding the reference frame), I had the idea that the light wave might become 'attached' to the plasma the light is travelling through i.e. the speed of light is referred to the average rest frame of the plasma charges. Now in the solar system the plasma is given by the solar wind which travels radially outward at a speed of 400 km/sec. But as the earth is moving perpendicuar to this at any point, this would merely result in an apparent reduction of the speed of light by 400 km/sec and thus practically still in the observed aberration value.

I think the attachment of the light wave to the plasma might probably depend somehow on the plasma density and wavelength of the light (somehow similar to the criterium I suggested for the redshift on my page www.physicsmyths.org.uk/redshift.htm ). This is why I am interested in observations for different wavelengths, because if the aberration disappears for certain wavelengths, this would practically establish a definite proof for this. But this is not a requirement for the theory to work. Otherwise one could also try to measure the apparent reduction of the speed of light by 400 km/sec, which would probably be difficult to observe in the stellar aberration data, but might be detectable for spacecraft propagation signals for instance.

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www.physicsmyths.org.uk
www.plasmaphysics.org.uk

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Thomas</i>
<br />Theory? I thought the theory for the Aberration of Starlight is assumed to be given by the Lorentz transformation.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Nope. No connection. The theory of aberration was complete almost two centuries before Lorentz and his transformations or Einstein and his special relativity.

As for implying a medium, the wave phenomena of light do that. Aberration simply shows that it cannot be a single, universal medium that provides a standard for absolute rest. For example, the aberration of stars and planets are one thing. Yet the aberration of things inside the Earth's gravity field (such as the Moon, artificial satellites, and streetlights) is close to zero.

This is most readily explained by Lorentzian relativity, wherein every local gravity field entrains the local aether and sets up its own standard of rest. Once you appreciate that point, the concept of elysium will make a whole lot more sense to you. -|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>
<br /><blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Thomas</i>
<br />Theory? I thought the theory for the Aberration of Starlight is assumed to be given by the Lorentz transformation.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Nope. No connection. The theory of aberration was complete almost two centuries before Lorentz and his transformations or Einstein and his special relativity.

As for implying a medium, the wave phenomena of light do that. Aberration simply shows that it cannot be a single, universal medium that provides a standard for absolute rest. For example, the aberration of stars and planets are one thing. Yet the aberration of things inside the Earth's gravity field (such as the Moon, artificial satellites, and streetlights) is close to zero.

This is most readily explained by Lorentzian relativity, wherein every local gravity field entrains the local aether and sets up its own standard of rest. Once you appreciate that point, the concept of elysium will make a whole lot more sense to you. -|Tom|-<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Hi Tom,

I mostly agree with you about that, but I would suggest that the gravity fields are “generated” by astronomical bodies and the fields themselves constitute the “local ether”, rather than the gravity fields “entraining” any external ether.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by DAVID</i>
<br />I mostly agree with you about that, but I would suggest that the gravity fields are “generated” by astronomical bodies and the fields themselves constitute the “local ether”, rather than the gravity fields “entraining” any external ether.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">See the book <i>Pushing Gravity</i> and the several related articles on this web site. Gravitational force and gravitational potential almost certainly are comprised of entities that do not (mainly) come from the source mass. (How else can you get a force that acts as if it were attractive? Things coming out of the Earth, whether particles or waves or wavicles or something else, can only repel things they hit.)

All the source mass needs to do is block some gravitons, thereby setting up an attractive force on nearby elysium (light-carrying medium) as well as everything else in the vicinity. -|Tom|-

Ok, Tom. Let me think about that for a while.