There’s a question I’ve had knocking about in the back of my mind for a while now about Jason Lisle’s Anisotropic Synchrony Convention and whether there could possibly be a way to falsify it.
In recent years, there have been observations made of supernovae appearing as multiple images in the sky. as a result of gravitational lensing from galaxies in front of them. For example, Rodney et al (2021) observed the same gravitationally lensed supernova, AT 2016jka, appearing three times with relative time delays of <200 days.
I would have thought that if the ASC were correct, and light really were travelling towards us at infinite speed and away from us at c/2, then all these images would appear at exactly the same time. However, this is not the case: the three images appeared with delays of <200 days between them, while a fourth appearance has been predicted to appear sometime between 2035 and 2039.
Is my thinking correct here, or am I missing something?
I think technically what goes on in GR is that it becomes impossible to define Lisle’s ASC except locally (if you try to extend it too far, the past light cone can end up self-intersecting, giving inconsistent assignments of simultaneity, etc - which is exactly what happens in gravitational lensing).
Nevertheless I suspect the idea could still be made to work with an appropriately gerrymandered foliation of space-time - likely the result would be the inward speed wouldn’t be infinite, just arbitrarily high, and it would vary across time and space in just such a way as to save the appearances.
I just like how you worded that, so I’m generating more copies.
I suspect that the sort of gerrypokery needed to correct one case of gravitational lensing will necessarily generate a multitude of new inconsistencies.
I have no idea; I haven’t really looked into it. I just suspect something like a GR-compatible (or nearly compatible) version of ASC is possible, from thinking about the geometry of foliations.
