Science Saturday: Beauty in Science

[zookarama]

Seems like I read a short story by Larry Niven (I think) in which a very small black hole is created and it makes its way to the earth's core where it orbits around, creating lots of mortal mischief. By the end of the story, the problem is somehow solved. I've shed most of my SF library so I haven't an archive here to search. Anyone else familiar with this one? Niven was/is great for his expositions of these 'hard' science quandaries.