NASA_
Bildquelle: NASA, MODIS Rapid Response System
NASA still images; audio files; video; and computer files used in the rendition of 3-dimensional models, such as texture maps and polygon data in any format, generally are not copyrighted. You may use NASA imagery, video, audio, and data files used for the rendition of 3-dimensional models for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages. This general permission extends to personal Web pages.
This general permission does not extend to use of the NASA insignia logo (the blue „meatball“ insignia), the retired NASA logotype (the red „worm“ logo) and the NASA seal. These images may not be used by persons who are not NASA employees or on products (including Web pages) that are not NASA-sponsored.
NASA should be acknowledged as the source of the material…