If you’re of the, um, geekier persuasion you’re undoubtedly aware of xkcd, the science and technology-oriented web comic by Randall Munroe. Back in April of 2013 he started a comic called “Time” that readers soon discovered was being updated every half-hour with a new frame. It appeared to tell the story of two people building a sand castle. But over time (see what I did there?) it became obvious that a lot more was going on. Exactly what was going on was cleverly shown and discoverable by those with an astronomical background. He finally finished it on July 26th and now the story behind it has been revealed.