discovered

http://www.npr.org/blogs/krulwich/2013/01/10/169047159/the-oldest-rock-in-the-world-tells-us-a-story?utm_source=NPR&utm_medium=facebook&utm_campaign=20130111 Earth was only 150-300 million years old and it formed in liquid water... Exciting stuff if you understand the implications.

Popular history says Columbus, but long before Columbus there were the Vikings and possibly other explorers reaching the United States from across the Atlantic. In addition there were Indians living in the United States, and also a link-up with Asia. What are your thoughts about who the...