the huge amount of stars all clustered together at the centre of our galaxy, the Milky Way, means that there is more than likely a huge black-hole there that constantly sucks in an destroys more and more stars from the rest of the galaxy. The centre of the Milky Way is called “Sagittarius A*” http://en.wikipedia.org/wiki/Sagittarius_A*
Yep! Scientists are pretty sure that we’ve got a super-massive black hole in the centre of our galaxy. They’re using telescopes to try and provide evidence of this, some of which are located in Hawaii (they’re super-high power telescopes), here’s a link to their site, which has some cool photos of the (massive!) telescopes they’re using: http://www.keckobservatory.org/
Astronomers actually hypothesise that every galaxy might have a super-massive black hole at its centre…so there is lots of research in this that can still be done!