保护地球，探索宇宙，发现文明
2021年8月11日 Mammatus Clouds over Saskatchewan Image Credit & Copyright: Michael F Johnston Explanation: When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water ...
2021年7月19日 Framed by Trees: A Window to the Galaxy Image Credit & Copyright: Will Godward Explanation: The photographer had this shot in mind for some time. He knew that objects overhead are the brightest — since their light is scattered the least by atmospheric air. He also that knew the core of our Milky Way Galaxy was just about straight up nea...