By Lisle’s ASC, the speed of light as a function of direction relative to the observer (θ) is given by cθ = c/(1-cos(θ)), where θ = 0 indicates the direction directly toward the observer. Although he does not state it, I presume he is taking some sort of limit for the denominator, so that he is not dividing by zero.
Under ASC, the one-way speed of light when directed toward observers on earth is axiomatically infinite, even though the round-trip speed of light remains 3 × 108 m/s. Thus, the light from stars that are created on the fourth day will reach the earth essentially instantaneously.
My understanding of Lisle is that while his focus is on Earth, every point in the entirety of the universe observes any given event as it happens, as per his equation. Two remotely situated observers immediately detect incoming light or gravitational waves from any position in deep space, irrespective of distance traversed.
Lisle’s following assertions seem consistent with conventional understanding:
- It is not feasible to measure the one way speed of light.
- All methods of synchronizing clocks, such as slow separation or sending of a signal, are equivalent.
- Selection of a convention is a mapping function, and thus arbitrary.
Where Jason Lisle’s convention is distinct in its orientation to observers. As far as I can tell, usually discussion and experimentation around the isotropy of the speed of light concerns differences that may exist with respect to direction in a given frame. This is not Lisle’s interpretation. According to him, two gun slingers who face each other with dueling laser guns will have light propagating towards both targets at infinite speed, while that same light will be propagating away from the laser guns at half the round trip speed of light, so that there can be no defined speed of light that can be assigned to the space where those beams meet in the middle.
Gravitational waves are clearer in that they travel at the speed of light, but without concerns for line of sight or obstructions, the processes which produce them are short and sharp compared to those for light, and detection facilities must put effort into precise timekeeping in the course of their investigations.
Should gravitational wave events impinge on the earth from anywhere on a three dimensional axis, if those waves propagate at infinite speed, they will arrive instantaneously at each detector station. All observatory stations will timestamp any events with the same pattern irrespective of direction. It does not matter if the stations were synchronized under assumptions of ESC, ASC, or set using knock off watches from a street market. What matters for this point is not the accuracy of triangulation, just that the pattern of timestamps would be identical regardless of the direction of the source on the celestial dome. Therefore, under ASC, triangulation is impossible. Note that this same consideration does not apply if light is asymmetrical in a fixed direction. This is not an argument that two way speed of light must equal the one way, only that at a given time there must be directionality if timestamps are to be consistent with direction of propagation.
I am emphatically not objecting to the idea that the speed of light can be different by direction. Rather, it is to point out that Jason Lisle, in setting the speed of light to be in respect to the observer rather than a given frame, is positing that the speed of light is infinite from any direction, and therefore differential times of arrival cannot be used to determine direction. If a person looks up at a clear night sky, she will see constant light from stars from every bearing. According to Lisle’s convention, the light from all these stars has arrived instantaneously. Thus, the speed of light has nothing to do with direction in an inertial frame. Light travels at different speeds for two facing observers with dueling laser guns even if they are close together in the same inertial frame.
My questions for Lisle would be, one, if light is instantaneous to the observer from all directions, how could the time interval for timestamps vary by direction? Two, if the intervals for the timestamps are in fact identical regardless of direction, how would it be possible to triangulate the gravitational wave source? This is a work a day practical matter of real world operation for astronomers, not just some coordinate system convention. I would suggest that Lisle’s ASC predicts that triangulation is not possible, and the fact that triangulation has been done falsifies his observer centric version of light travel anisotropy.
I am no physicist. If I am just not getting it, I would be happy to have an explanation of how to triangulate using ASC assumptions, without recourse to conventional coordinates.
Gravitational waves are line of sight
Triangulation is time of flight
Therefore, Lisle is not right