Images de la Terre : vraies photos NASA (domaine public), reduites pour les shaders.

terre_jour.jpg  NASA Earth Observatory, Blue Marble: Next Generation (decembre 2004, topographie + bathymetrie), Reto Stockli.
                https://eoimages.gsfc.nasa.gov/images/imagerecords/73000/73909/world.topo.bathy.200412.3x5400x2700.jpg
terre_nuit.jpg  NASA Earth Observatory, Black Marble 2016 (Suomi NPP VIIRS), Joshua Stevens / Miguel Roman.
                https://eoimages.gsfc.nasa.gov/images/imagerecords/144000/144898/BlackMarble_2016_01deg.jpg
nuages.jpg      NASA Goddard Space Flight Center, Blue Marble: Clouds, Reto Stockli / Robert Simmon.
                https://eoimages.gsfc.nasa.gov/images/imagerecords/57000/57747/cloud_combined_2048.jpg
