I’ve been doing a final project for one of my classes which entails reading the entire xkcd archives, repeatedly, for homework (on which more later; yes, sometimes my life is awesome).
Today’s xkcd has the following alt text:
Telescopes and bathyscapes and sonar probes of Scottish lakes, Tacoma Narrows bridge collapse explained with abstract phase-space maps, some x-ray slides, a music score, Minard’s Napoleonic war: the most exciting new frontier is charting what’s already here.
(Emphasis mine.) I choose to treat this as a secret shout-out to librarians.