Thumbnail: Earth from space based on data from multiple satellite missions and the talents of NASA scientists and graphic artists. (Public Domain; NASA images by Reto Stöckli, based on data from NASA ...Thumbnail: Earth from space based on data from multiple satellite missions and the talents of NASA scientists and graphic artists. (Public Domain; NASA images by Reto Stöckli, based on data from NASA and NOAA. Via Visible Earth)