BQ How close would the earth have to be to a black hole for it to completely suck it in.
BQ1 Is there one in the middle of our galaxy
Answer on Do suppermassive black holes exist?
Yes there is one in our galaxy. Its mass is 4,000,000 times that of our sun (our sun is 1,000,000 times more massive than the earth). It can be measured and its place in our Galaxy's heart pinpointed because of measurements of the stars surrounding it. Some of the stars around it move light-weeks in a single month because of the influence the mass of the black hole has on them. Our super-massive black hole is nothing great as they go, but its not a small one either. The Galaxies whose nucleus have Super-massive Black Holes are called "active" galaxies.