Composite image of a cloud in the Martian sky captured by Curiosity rovers Mastcam after sunset on 27 Jan 2023. Studying the colours of such clouds can reveal infromation about the particle size within them and the way they grow. This cloud is thought to be higher than most clouds on Mars. The conditions at such an altitude on Mars would suggest that this cloud is formed of carbon dioxide (dry ice). Clouds are relatively rare on Mars, only forming in certain areas when Mars is furthest from the Sun. Scientists hope to study clouds such as these, which appear earlier in the Martian year, to better understand how clouds form on Mars.