I was interested to find this piece on one of the aggregators about a small oversight in previous measurements of the Milky Way (you know, the galaxy that we live in).  Turns out that astronomers now think that the whole shebang is 50% larger than previously believed...oops.  Who knew (answer:  no one ever) It turns out that their trigonometric parrallax is respectably more precise than yours is.

A great piece of evidence when discussing just how much of the basic facts of existence that we still don't have a clue about.  At least I can buy me some of these!