Retrograde motion for Mars, illustration. Because the Earth (blue) moves faster in its orbit than Mars (red) does around the Sun (yellow), Mars appears at times to move backwards across the sky relative to the background of stars (top) when viewed from Earth. This apparent backwards movement is known as retrograde motion. | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / TIM BROWN |
Taille de l’image : | 3780 px × 5027 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |