Photon Sphere and time travel around a Black Hole?

[infinitebubble]

Reading the post below on event horizon of a black hole (BH) got me thinking about the photon sphere of the BH. We all know light will travel around this photon sphere and how light from a source would completely travel back to it's source if one could see it real time, we all know this from relativity.

Now I postulate if a vehicle could theoretically be at this photon sphere and travel around it, we know it would see itself from the light traveling back and they would eventually see themselves... would TIME be the same or would as I suspect they would see themselves in the future?

 

[jedishrfu]

No, I'd say they would see a past version of themselves not a future version.

The book the Science of Interstellar shows world lines of photons looping around a black hole before being emitted back into space.

https://en.wikipedia.org/wiki/Photon_sphere

https://phys.org/news/2014-03-orbit-black-hole.html

 

[mfb]

You can reproduce all effects of the photon sphere with mirrors at home (although things like time delays will be too short to notice without sensitive equipment, of course). No time travel involved, and everything you see happened in the past.

 

[infinitebubble]

OK... perhaps I was seeing some time dilation as the light/vehicle traveled around the BH. But if you see your past then you would be in the future would it?

https://apod.nasa.gov/htmltest/gifcity/nslens_bh.html

 

[jedishrfu]

OK... perhaps I was seeing some time dilation as the light/vehicle traveled around the BH. But if you see your past then you would be in the future would it?

No, you would be here now in the present.

 

[infinitebubble]

No, you would be here now in the present.

Would this be the same for supermassive BH's on the order of millions of Suns?

 

[jedishrfu]

Would this be the same for supermassive BH's on the order of millions of Suns?

The photon sphere would just be larger for larger black holes, right? The light leaves your spaceship and then you see the back of your spaceship. You are in the present and the light you see is from your past.