Infrared is by definition not what you would think of as a color. The colors in that picture are false, and a stylistic choice made during the rendering process

Infrared is by definition not what you would think of as a color. The colors in that picture are false, and a stylistic choice made during the rendering process. It would be just as accurate to use shades of blue and make it look icy. Perhaps more accurate as the upper atmosphere portrayed here is very, very cold.