关于这张图
ISS034-E-024622 (5 Jan. 2013) --- Polar mesospheric clouds over the South Pacific Ocean are featured in this image photographed by an Expedition 34 crew member on the International Space Station. Polar mesospheric clouds—also known as noctilucent, or “night shining” clouds—are formed 76 to 85 kilometers above Earth’s surface near the mesosphere-thermosphere boundary of the atmosphere, a region known as the mesopause. At these altitudes, water vapor can freeze into clouds of ice crystals. When the sun is below the horizon such that the ground is in darkness, these high clouds may still be illum…
