http://globe.gov/explore-science/scientists-blog/archived-posts/sciblog/2010/02/10/earth-detectives-how-we-know-what-we-know/?utm_source=rss&utm_medium=rss&utm_campaign=earth-detectives-how-we-know-what-we-know Tue, 25 Mar 2014 04:27:31 +0000 hourly 1 http://wordpress.org/?v=