Alien night sky. Artwork of a large spiral galaxy,moons,planets (one at upper right),stars and a comet (upper centre) in the night sky of an alien (extrasolar) planet. This planet has oceans of liquid water and clouds of water vapour. If a planet is to have a surface temperature suitable for liquid water,and to retain an atmosphere,it must be a suitable size and distance from its star (on horizon,lower left). The number of habitable planets in the Milky Way galaxy is not known,but has been estimated at anything between 1 (just Earth) and as many as 10 billion. Many planets have already been discovered orbiting nearby stars | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Van Ravenswaay, Detlev |
Bildgröße: | 5976 px × 4394 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |