What is the regular size of a black hole in light years?

Answer 1

There is no particular size of a supernova black hole because they are usually caused by a large star. We do not know the exact size of our neighbor galaxy Andromeda that scientists are now saying that its going to crash into our galaxy and suck all of our planets into its black hole. Black holes can be big, but they are not nearly big enough to be measured in light years. Black holes can also be very small; perhaps as small as a grain of sand or even smaller. A light year is the distance light travels in one earth year in a vacuum. It is an enormous distance. Comments added by Urlicha25: Black holes are the result of a ‘mass(most likely a star)’ that collapses on itself and creates a ‘quantum’ singularity with a height-width-length size of zero in all directions. Its dimensions are far less than that of a grain of sand. Its dimensions are simply zero in all directions. A black hole has no physical size. Area of effect is more useful conversation when discussing the size of black holes. Depending on the mass of the black hole, it’s ‘event horizon’ expands. The event horizon is a ‘point of no return’. Once you cross this ‘proverbial line in the sand’ you can not return. Thus the ‘size’ of the black hole is still zero in dimension but its critical ‘area of gravitational effect’ is based on its event horizon radius which varies on cumulative mass of the black hole. In summary, back holes have no size. Their event horizon, the point of no return, varies based on the mass of the black hole. The center of our galaxy has a super massive black hole and we are tracking several stars, same size or larger than our sun, orbiting this black hole. If those stars fall into its event horizon and can’t maintain a stable orbit, they will add/feed the black hole and increase its event horizon’s radius in all directions. As for the rest of us, we’ll just keep orbiting the central black hole in the center of our galaxy. I’d guess our sun will expand into a red giant and eat our planet before we have any issues of being added to the mass of our galaxy’s central black hole.