Henry Reich, through his MinutePhysics YouTube channel, has posted part two of his universal universe series of video.
Last week we saw a discussion about how to define what we mean when we say "the universe", and this week he sets out to discuss how we measure how big it is. As usual with physics, it's not as easy as getting out our tape measure.
I still can't wait for the discussion of parallel universes, in which I'm more famous than I currently am. Fingers crossed!
Keith Shaw rounds up the best in geek video in his ITworld.tv blog. Follow Keith on Twitter at @shawkeith. For the latest IT news, analysis and how-tos, follow ITworld on Twitter, Facebook, and Google+.