Two of the three most profound discoveries we have ever made in science have to do with earth history. The three are, in no particular order, 1) the scale of the universe 2) the age of the universe and our home planet, and 3) the unity of life on Earth by descent from common ancestors. This blog invites comments and questions about the last two, how they are perceived by society, and what they imply for what we should be doing as a species.