Friday, September 05, 2008

Down to earth

Here's another picture from yesterday's Chemistry of Life class. I'm not sure what the white center is for, or why you'd want to make it seem that the earth had somehow come full circle with the arrival of us - Doomsday clock, anyone? - but I'm confusing messenger and message. The relevant point is that there has been life of some kind - the skinny purple arc - for about most of the history of the planet.