This figure has two parts. On the left hand side is a photograph of the Earth surrounded by the black background of space. The whole globe is shown, which has a pattern of blue water, and green and brown continents. Clouds form white streaks and swirls obscuring details of the continent and water bodies in view. On the right hand side is a photograph of Mars. It also shows the full globe of the planet, coloured bright orange and brown, surrounded by the black background of space. Across the middle of the globe runs a dark brown feature, which looks like a scar but is a deep valley.