Based on what we've observed, one could likely estimate the amount of accretion needed to make Sag A* visible from Earth. Or bright enough to fry us. It'd be a

Based on what we've observed, one could likely estimate the amount of accretion needed to make Sag A* visible from Earth. Or bright enough to fry us. It'd be a huge stretch for me to do that. But I bet that it's a lot less than Andromeda. I mean, there could be a substantial black hole, maybe 50-100 years out, and I doubt that we could detect it now :)