I just wanted to start by stating that I have been a long time reader of these forums (this is my first post) and want to thank all of you out there for taking the time to share with the rest of us your knowledge and insight. I have fairly recently become interested in the topic of our universe and our origins and was curious about any good literature on the topic. I dont have a background in physics or calculus so I am looking for something that is very much for a beginner. I also had a fairly basic question. I know our universe is in the region of 13 billion years old or so, but what about our earth? Also, How have we come with these numbers and what evidence do we have to support it? Thanks ahead of time for taking the time to read this.