Night Shining Clouds
Polar mesospheric clouds—also known as noctilucent or “night shining” clouds—form between 76 to 85 kilometers (47 to 53 miles) above the Earth’s surface, near the boundary of the mesosphere and thermosphere, a region known as the mesopause. This astronaut photograph was taken when the International Space Station (ISS)was over the Pacific Ocean south of French Polynesia.
—NASA