Planet Earth and the other bodies of the Solar System are 4.5 billion years old. They reside in a galaxy (the Milky Way Galaxy) that is 12-14 billion years old, and are part of a universe that is 13-15 billion years old. In Ancient Earth, Ancient Skies, G. Brent Dalrymple, a geologist and widely recognized expert on the age of Earth, reviews the evidence that has led scientists to these conclusions and describes the methods by which this evidence has been gathered.