We know that light and even gravitational waves propagate at the speed of light.
So if something catastrophic happened to the black hole at the center of our galaxy (about 26,000 lightyears away), would there be any way for us to have advance knowledge of it before we could observe it with telescopes or before we could measure the gravitational changes?
Ludicrous example: say the black hole at the center of the galaxy disappeared 25,999 years ago. Is there a way we would have known about it by now, or do we just have to wait out another year to see if we’re all screwed?
Yes, let me lawyer the question ….
We could know about it in only 26,000 years due to the speed of light and gravity waves. However I’m not sure how it would affect us at all …
Perhaps there’s a burst of particles going less than the speed of light. We would know about it before those particles got here.
Perhaps you mean the disappearance of the strong gravity well at the center might affect us: I imagine any changes to the structure of the galaxy or it’s movement would take much much much longer to affect us