Photorealistic digital image representing an astronaut surfing on top of a green rocket through the galaxy. The astronaut is in a dynamic surfing pose, riding the rocket like a surfboard. The galaxy background should have vibrant colors, with stars, planets, and cosmic elements to enhance the space theme. The focus should be on the astronaut and the rocket, showcasing the adventurous and dynamic aspect of the scene. The rocket should be prominently featured, with detailed textures and highlights to make it stand out.