Stellar Aberration Versus the Aether
by Sid Deutsch

     Around 1864, Maxwell “invented” the aether. In 1887, the Michelson-Morley experiment showed that the aether, if it exists, is carried along as an “atmosphere” surrounding any massive object. This can be due to gravitational attraction, as is the case for Dark Matter. For the earth, it was generally assumed that the earth’s aether would grab an incoming photon and steer it in the direction of aether motion, thus canceling stellar aberration. In the present paper, it is conjectured that, because of the nature of spin propagated by aether particles, the earth’s aether does not affect the flight path of a photon. In general, therefore, we cannot detect the aether turbulence associated with moving discontinuities because light (or any EMF) does not bend, when it encounters a discontinuity, unless there is a change in permeability and/or permittivity.
     There is no way that light can propagate unless it is carried by a medium; in other words, it is impossible for light to penetrate a real vacuum. This assessment holds for an electromagnetic field (EMF) in general. Accordingly, around 1864, James Clerk Maxwell and his contemporaries “invented” the aether.  The aether is a mysterious substance that fills the universe; in the present paper, it defines the universe. It has been conjectured that the aether consists of minuscule particles, and the spin of an aether particle (EP) is the embodiment of an electric, or magnetic, or electromagnetic field.

     The propagation of an EMF is analogous to the way sound is transmitted: For sound, one molecule pushes against the next molecule, followed by a “hole” that is filled as the next molecule rebounds. This oscillation is propagated through the medium consisting of any material substance: solid, liquid, or gas. For an EMF, it is conjectured that the spin of an EP is passed on to the next EP at the speed of light, c = 300 million m/s in a “vacuum.”  
 
     In 1887, the Michelson-Morley experiment (which is not further described here because it is very well known) showed that the aether, if it exists, is carried along by the earth. In other words, every large object (earth, moon, sun and so forth) is immersed in its own aether, and carries it along similar to the way in which the earth carries its atmosphere of air. This depiction may seem to be far-fetched, but remember that Dark Matter (DM) is gravitationally bound to the stars immersed in it; in fact, that is how the DM was discovered [1]. It is accordingly conjectured, in the present paper, that DM and EPs may be identical. The aether “atmosphere” is held in place via gravitational attraction to its massive base.

     Time has been a leisurely observer where the aether hypothesis is concerned. As Peter Galison wrote in his fascinating and informative book, “Einstein’s Clocks, Poincaré’s Maps” [2], “Earth’s motion through the aether could not be detected … and, therefore, so the argument went, Einstein concluded that the aether was ‘superfluous.’ ” Apparently, Albert Einstein was happy that his spacetime equations were correct; he had more interesting and important projects on his agenda than trying to figure out how an EMF propagates, so he abandoned the aether. Nevertheless, Henri Poincaré and many other scientists did not regard the aether as “superfluous.” Without a reasonable explanation for how an EMF can propagate in a vacuum, the aether hypothesis could never be laid to rest. In 1955, for example, a well-known textbook by W.K.H. Panofsky and M. Phillips [3] went into considerable detail to once again examine the hypothesis. Their conclusion was that the aether does not exist.

     The aether hypothesis is illustrated in the cross section of Fig. 1. The sun and earth are surrounded by an aether “atmosphere.” The latter undoubtedly trails off exponentially, but the worst case is depicted: There is a sharp discontinuity in going from the aether atmosphere to the interplanetary space. The latter region is represented by a cloud labeled “aether ‘background’.”

     This portrayal of the solar-system’s aether is an important bone of contention in the aether hypothesis. It implies (Panofsky and Phillips, pg 231) “that there exists a unique privileged frame of reference, the classical ‘aether frame,’ in which Maxwell’s equations are valid and in which light is propagated with the velocity c.” The background aether is undoubtedly drifting through intergalactic space, and it has to obey Einstein’s special relativity equations: With respect to an observer on an inertial platform (the earth), the component of the drifting aether that is moving toward (or away) from the observer becomes shorter. Also, a clock carried along toward (or away) from the observer becomes slower [4]. These spacetime effects are negligible unless the aether is drifting toward (or away) from the earth at a “relativistic” speed (at least one-third the speed of light). (One can also neglect the slight acceleration that the earth suffers because of its rotation, and orbit around the sun.) The most important reason for abandoning the aether concept is that the “background” aether has never been detected. 
         
     Although the large-scale manifestations of the aether have not been uncovered (aside from the fact that a photon can propagate indefinitely, without loss to the medium), there is plenty of evidence that an aether may be involved in the weird sub-atomic effects of quantum mechanics [5].

     The aberration of stars has been cited as “proof” that the aether does not exist. Consider Fig. 2(a), where a telescope on earth is lined up with a distant star. In Fig. 2(b), at t = 0, a photon from the distant star enters the telescope tube. At t = 0⁺, the photon has progressed halfway down the tube. Because the earth’s orbit carries the telescope to the left, the photon’s relative motion is towards the right. At t = 0⁺⁺, the photon strikes the light-sensitive receiver (assumed to be a film in what follows) towards the right, as shown. The angular movement is given by the arctan of the earth’s speed (3 × 10⁴ m/s) divided by the velocity of light (3 × 10⁸ m/s), or 0.0001 (= 20.5"). Although it is minuscule, this amount of aberration is easily detected and measured.
Fig. 2- The basis for stellar aberration. (a) A telescope on earth is lined up with a distant star. For the sake of clarity, the sun is omitted. (b) The path of a photon that enters the telescope tube at t = 0. Because the earth’s orbit carries the telescope to the left, the photon’s relative motion is towards the right. The angular movement is 20.5".

     To round out the aberration phenomenon, Fig. 3(a) depicts the telescope six months after the view of Fig. 2(a). As shown in Fig. 3(b), now the earth is moving to the right, so the star’s photons drift to the left. If the film is repeatedly exposed for a year whenever the telescope is lined up on the star, a circle of aberration is found; its diameter corresponds to 41" of arc.

     It has been assumed generally that the earth’s aether, moving with respect to the sun, would grab the incoming photon, steering it to go straight down the center of the telescope’s tube. This is illustrated in Fig. 4(a), where the photon is deflected towards the right. In Fig. 3(b), this would cancel the photon’s leftward drift, yielding a film exposure free of aberration. The details of the photon’s path of Fig. 4(a) are described in Fig. 4(b). For the sake of clarity, only the aether particles involved in the photon's propagation are shown. According to the aether theory conjecture, the spin at t = 0 embodies the photon entering the upper-left-hand EP. At t = 2, 4, 6, …, spin of the EPs corresponds to the photon at t = 2, 4, 6, …. (The small arrow is symbolic, and is not meant to show the actual spin.)
     Since the characteristics of the aether are not known, it is conjectured in the present paper that the interpretations of Fig. 4 are incorrect; that, in fact, the moving aether does not affect the flight path of a photon. This is illustrated in Fig. 5. In (a), the photon’s path is a straight line, despite the aether moving in the lower section of the drawing, so that stellar aberration does occur despite the earth’s aether atmosphere. The EP spin details are shown in Fig. 5(b). Photon paths are as shown in Figs. 2 and 3.
     What is the basis for the claim that the path of a light beam is independent of aether motion? It is that the velocity of light does not change in crossing the motion discontinuity of Fig. 5(a). As the spin is transmitted from one EP to the next at the speed of light, it is blind to relative motion provided the velocity of light remains constant in going from one region of space to the next.

     This is in contrast with a beam of light passing from air to glass (or vice versa) as depicted in Fig. 6. The diameter of each EP does not change, but the velocity of light is given by 1/(µε)^1/2, where µ is magnetic permeability and ε is electric permittivity. In glass, the permittivity is greater than in air, so the electric field changes and the corresponding spin, in glass, is different from what it is in air. The reduced velocity of light causes the beam to bend when it crosses the permittivity discontinuity.
     The motion-independence conjecture has far-reaching consequences for the universe. Returning to Fig. 1, a beam of light leaving the sun, crossing the moving “background” aether field, and crossing the earth’s aether atmosphere (moving “northward” in this figure) follows a straight-line path. This agrees with the constant velocity of light in a non-accelerating medium (the centrifugal accelerations of the earth are negligibly small).

     The universe is a huge cloud of aether. Here and there are minor discontinuities formed by stars, planets, and the like. We cannot detect the turbulence associated with these discontinuities because light (or any EMF) does not bend in encountering a discontinuity unless there is a change in permeability and/or permittivity. (This ignores the slight bending associated with spacetime curvature.)

     Space has no meaning beyond the edge of the aether cloud. Are permeability and permittivity everywhere constant? Probably not, as the cloud expands (or contracts). It is foolhardy to assume that the natural constants, such as the velocity of light, have been, and will be, invariant over all space and time [6].
  
     [1] K.C. Freeman, “The Hunt for Dark Matter in Galaxies,” Science, vol 302, pg 1902, 12 Dec 2003.
     [2] P. Galison, Einstein’s Clocks, Poincaré’s Maps, New York, Norton, 2003, pg 324.
     [3] W.K.H. Panofsky and M. Phillips, Classical Electricity and Magnetism, Reading, MA, Addison-Wesley, 1955.
     [4] N.D. Mermin, Space and Time in Special Relativity, New York, McGraw-Hill, 1968.
     [5] S. Deutsch, Return of the Ether, Mendham, NJ, SciTech, 1999.
     [6] J. Magueijo, Faster Than the Speed of Light, Cambridge, MA, Perseus, 2003.       home