This means that NLC are illuminated by the Sun's rays in the middle of the night and glow in the sky long ... the clouds they form ghostly curls, ribbons, and tendrils of silvery-blue light ...

Six planets are parading across the sky, appearing as some of the night's brightest stars. A few easy tips can help you identify them.

Noctilucent clouds shimmer above ... the sun has set in Gale Crater, the clouds are high enough in the atmosphere that the sun still shines on them, making them seem to almost glow in the sky ...