Question

What, excluding water vapour, do night shining clouds consist?

Answer 1

Noctilucent, or night-shining, cloudsare the highest clouds in Earth's atmosphere.

Answer 2

Noctilucent, or night-shining, clouds are the highest clouds in Earth's atmosphere. They form in the middle atmosphere, or mesosphere, roughly 80 kilometers (50 miles) above Earth's surface. The clouds form when water vapor freezes around specks of dust from incoming meteors.