Holes in the Head

In an effort to understand the universe and, most importantly, ourselves, we are accumulating a vast reservoir of knowledge. The containers into which we our this knowledge are often somewhat leaky - especially when its just in our heads! - but, by and large, we seem to have increased our store. But how long will it actually endure... surely nothing short of a global catastrophe will eliminate everything? Yes, I probably have better things to worry about it, but the thought of that sizable asteroid headed our way looms large in my thoughts from time to time.