Quote from Raj Koothrappali in the episode Spoiler: Corn is Delicious
Raj Koothrappali: Are you familiar with the galaxy GN-z11? Stuart: Um, no. Denise: No. Raj Koothrappali: It's the most distant galaxy the Hubble telescope can see, and guess what? Stuart: Mm... Raj Koothrappali: Don't bother. It's a rhetorical question. The whole damn thing... gone. Denise: How can a galaxy disappear? Stuart: You sure the Hubble telescope doesn't have some schmutz on it? Raj Koothrappali: It's the Hubble! It doesn't have schmutz! Stuart: Schmutz happens to everything.