Welcome aboard our spinning Earth as it travels on its immense journey around the Sun. Bring a bowl--and come along! Help collect the ingredients for a cake as big as a year, and see how every circle around the Sun . . . equals one. One what? One birthday cake!     For fifteen years, On the Day You Were Born has been the classic book to welcome new babies into the world. Now, this jubilant companion celebrates every year thereafter in the life of a child--and of our great green planet Earth.     Includes delicious cake and frosting recipes, explanations of how the years are marked in nature, and a section called "How many days to your birthday?" so kids can actually find their own special day.