I Gravity of the Sun: Einstein's Calculation and Beyond

[Nik_2213]

IIRC, the Sun's gravity was calculated by Einstein et-al to provide a 'focus' about 550 AU out. Current value is ~542 AU.
Aside from effects due solar oblateness, frame dragging etc, may I assume this value also applies to eg neutrinos, gravitational waves etc etc ??

 

[Ibix]

Yes and no.

The calculation is for rays grazing the Sun, and I would expect that neutrinos and gravitational waves grazing the same surface would focus at the same distance, give or take a small bit. But gravitational lenses are terrible lenses, and the focal distance depends very much on the distance of the ray from the Sun center at perihelion. And I suspect the Sun is transparent to neutrinos for some depth below where it becomes opaque to light. And it's transparent to gravitational waves right through. So you may well be able to find focuses for them closer to the Sun.

Note that we don't have good enough neutrino or gravitational wave astronomy instruments to test anything like gravitational lensing of these things, so this is purely theoretical at this stage. We've no reason to doubt it works, but it hasn't been tested.