西藏上空的气辉涟漪
2022年11月20日 Airglow Ripples over Tibet Image Credit & Copyright: Jeff Dai Explanation: Why would the sky look like a giant target? Airglow. Following a giant thunderstorm over Bangladesh in late April, giant circular ripples of glowing air appeared over Tibet, China, as pictured here. The unusual pattern is created by atmospheric gravity waves, waves of alternating air pressure that can grow with height as the air thins, in this case about 90-kilometers up. Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence, the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night sky from ever being completely dark. Tomorrow’s picture: butterfly sky 西藏上空的气辉涟漪 图像提供与版权: Jeff Dai(戴建峰) 说明:…