Have black holes been mapped?

You do agree with huge gravitational pull around somewhere in a galaxy.Huge gravitation is generated only by huge mass.Existance of huge mass but no detection by spectroscopy so far is absolutely in keeping with it's name ,the black hole.

We know the undercurrent in a river is how dangerous but we can not estimate it's gravity from the surface.But we may map it's severity by throwing a piece of paper on it which will be spiral inward the water instantaneously.Similarly if matters are gone spiral inward like a flow of gas into some unknown

invisible area there must be something dangerous with enormous gravity.May be a black hole may disintegrate but they are must be there.

"...do we actually know where they are?..."

Yes we do. There are two main methods for locating black holes --

1. Look for a black hole's gravitational influence on any nearby stars;

2. Look for concentrated, super-dense areas of high-energy radiation which is caused by gas and dust being drawn into a black hole and accelerated to near the speed of light. See some artist renditions of this here =>http://www.universetoday.com/38146/black-hole-pict...

Many have. The nearest is about 1,600 light years away; the most powerful we know of is at the center of galaxies - including ours. To my knowledge, about 250 'free floating' black holes have been plotted; all are very far away from Earth.

here's the story: http://www.space.com/scienceastronomy/astronomy/v4...

Other than every one every found has been at the center of a galaxy, no.

That is pretty obvious evidence!! Black Holes DO NOT just float through space, sucking up light and gravity! No, they are CAUSED by the implosion of a sun. In fact, that sun must be more than 2 times the size of OUR sun in order to produce a Black Hole! "Mini" Black Holes just dissipate and die.

So, EVERY black hole known is at the center of a galaxy -- and THOSE are EASILY mapped.

Black holes have been mapped because we know the distance to them.

We know where some of them are. We do not know where all of them are. Scientists cannot see the entire universe, so we do not know where all of them are. We actually cannot see our entire galaxy so there may be some in our galaxy that we do not know about.

Yes, scientist can detect them like you mentioned.

No, they're almost, if not impossible to map because they generally travel at the speed of light, in addition they're impossible to identify unless they are massive. However scientists are certain that they are not in any galaxies around us. I hope this helps.