The car-sized Curiosity rover has spotted evidence of once quite hospitable environs on Mars.

Latin for “night shining,” noctilucent clouds (also known as twilight clouds) are responsible for Earth’s vibrant red, orange, and purple dawn and dusk skies. If the conditions are just right, they sometimes even take on an iridescent,

At the surface, Mars is a desolate, barren world with a rocky landscape, massive dust storms and extreme temperature swings. However, a rover recently captured a splash of color in the sky as rare clouds drifted overhead.