Optical photograph of the Ring Nebula (M57,NGC 6720),a planetary nebula about 2000 light years away in the constellation of Lyra. The nebula is a shell of gas ejected from the central star some 20,000 years ago. The gas glows because it is illuminated by ultraviolet radiation from the hot,blue central star. Planetary nebulae are so called because they resembled planets in 19th century telescopes | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Gordon, Kim |
Taille de l’image : | 4044 px × 5669 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |