Have gravitational waves been observed?

They certainly seem to be trending on Google searches:

Tune in tomorrow morning at 7:30 AM to hear an announcement from Caltech, MIT and the Laser Interferometer Gravitational-wave Observatory (LIGO): www.caltech.edu.

Changing font in matplotlib

In order to change the font of text in a matplotlib figure, I needed a list of the available fonts. It took me a frustratingly long time to find this stack exchange answer, so I thought I would record the solution here.

import matplotlib.font_manager
{f.name for f in matplotlib.font_manager.fontManager.ttflist}

Then just choose a name from the set and insert it into a text command, e.g.

import matplotlib.pyplot as plt
plt.ion()
plt.title('title', fontname='FreeSans')