Thanks to Brain Pickings this morning I learned that C.G.P. Grey is back with another good visual explanation. This time he tackles Pluto and its status as a planet or not a planet. But there’s more than that to the video as it addresses a bit of history of astronomy and the scale of objects in the universe. You can read the transcript of the video and see a couple of minor corrections to the video on the C.G.P. Grey blog.