Dear folllowers,
Imagine you are in 1905, where experiments known today were not done.
Does aberration of light exist for a source horizontal to a moving frame?
Such a phenomenon (which mathematical reinterpretation should be done) wouldn't it explain c constancy in case of galilean addition of speed?
(The source being independant, every photon evolves in the detection frame where information is delayed relative to the real position giving c constant instead of galilean addition).
Aberration was known as early as the late 1600's and specifically measured by Bradley in 1727 so was well established before 1905.
- "Aberration is historically significant because of its role in the development of the theories of light, electromagnetism and, ultimately, the theory of special relativity. It was first observed in the late 1600s by astronomers searching for stellar parallax in order to confirm the heliocentric model of the Solar System. However, it was not understood at the time to be a different phenomenon.[1] In 1727, James Bradley provided a classical explanation for it in terms of the finite speed of light relative to the motion of the Earth in its orbit around the Sun,[2][3] which he used to make one of the earliest measurements of the speed of light. However, Bradley's theory was incompatible with 19th century theories of light .."
https://en.wikipedia.org/wiki/Aberration_of_light
Understanding aberration as a result of the unified theory of relativity (time dilation) and quantum theory (the Copenhagen school) indicating that phenomenon is observer dependent. That's why ancient people in their understanding to astronomy and cosmology, they predicted the motion of planets and galaxies is related to the existence of the observer on earth. That means the motion of the planets and Galaxies can't be separated with the existence of the observer on the ground. That is the consequence of quantization of gravity. But we understand now the laws of physics are the same for all observers.
Aberration is a change in the angle. So how would you even define what you mean by ``aberration of light exist for a source horizontal to a moving frame?''
Unless you can define the phenomenon, you might not recognise it when you see it!
Yeah! So what is you concept of aberration when the rain falls horizontally and the guy with the umbrella runs horizontally?
FL: ?? "rain falls horizontally" ??
Typo ?
NG: I know that aberration is a change in the angle. But isn't it also a change in the distance ..
Do you think that in your illustration, the man running changes the altitude of the cloud that produced the rain? It affects the angle only.
@Leyvraz,
Do you mean rain has a horizontal velocity?
If yes, the observer measures only the horizontal velocity of the rain (speed of observer relative to source + speed of rain relative to source - aberration of rain)
If no (rain having no source is static relative to our picture frame), the observer measures his own velocity (0 + "speed of rain" - 0)
OK, horizontal rain may have been a bad idea. I was asking what happens if the velocity of the guy with the umbrella is parallel to that of the rain. What is aberration then? Sticking to vertical rain, what happens if the gentleman with the umbrella is rising vertically? What is the aberration?
That seems to be what Ni Ge is talking about.
NG: I mean a change of measurement. The diagonal is what is seen by the observer. The distance seen of the cloud is not the same as the distance of the cloud.
It depends on your method of measurement. For example if you use parallax then you can calculate the difference in the aberration for your two observations at the ends of the baseline and see how it affects the derived distance.
https://en.wikipedia.org/wiki/Parallax
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