Recently I heard that astronomers had observed the same supernova exploding four times, and that it had something to do with gravitation and optics. It was one of those moments where I heard (or read) the headline but didn't catch the details, and I tucked it into the "look it up later" file. (This file fills most of my neural storage at this stage.)

Thankfully, Dennis Overbye has written a great explanation of the phenomenon for the New York Times, and produced the companion video below explaining what happened, how it happens, and why it's related to Einstein. Although science is just as much about disproving theories as proving them, this is a lovely example of how Einstein was proven right in his own time, and continues to be. Have a look:

If you're not a video person, Overbye's article is a more detailed look at the same subject (but, beware, the afore-linked page autoplays the video with an ad—you may want to pause it).