Today is Earth Day 2012. Organizers are calling on over one billion people around the globe to participate and help “Mobilize the Earth”. The spectacular “blue marble” image of the earth (pictured below) is the most detailed true-color image of the entire Earth to date. Provided by Visible Earth/NASA, this is one of many stunning images freely available to educators, scientists, museums and the public. (MORE)

Credit: NASA Goddard Space Flight Center Image by Reto Stöckli (land surface, shallow water, clouds). Enhancements by Robert Simmon (ocean color, compositing, 3D globes, animation). Data and technical support: MODIS Land Group; MODIS Science Data Support Team; MODIS Atmosphere Group; MODIS Ocean Group Additional data: USGS EROS Data Center (topography); USGS Terrestrial Remote Sensing Flagstaff Field Center (Antarctica); Defense Meteorological Satellite Program (city lights).