Known as "nacreous clouds" or "mother-of-pearl clouds," these clouds are a very rare phenomenon. Captured on Jan. 12, when the sun was located just below the horizon, the unforgettable appearance ...

Also known as nacreous clouds or “mother-of-pearl clouds”, they form during winter and early spring in the polar stratosphere, the second-lowest layer of Earth’s atmosphere, which is ...

When clouds are both noctilucent and iridescent, they're called nacreous clouds, and under the right conditions, noctilucent clouds can take on an iridescent, mother-of-pearl quality. The ...