No, as both gravitational and em waves travel at the speed of light, the “we’re all screwed” things we could ever observe would only ever be slowed-down/distorted (by things that could even do such a thing like a black hole) as they approach us.
So it’d be a happy little surprise (short of worm-holes or tachyons existing), on year 26,000.
That’s not too say life as we know it would end immediately. We might make it generations before the real chaos affected us on earth. On a smaller scale, if the sun blipped out of existence, sure, we’re 💯 doomed and we’d know it after 8.3 minutes, but some of us might make it a solid week before all life on earth was expunged 😅.
if something happened to the black hole at the center of our galaxy, could we know about that problem before it affected us?
We know that light and even gravitational waves propagate at the speed of light....