Astronomy Picture of the Day

Good morning RP. Today's Astronomy Picture of the Day is titled "Noctilucent Clouds, Reflections, and Silhouettes." Noctilucent clouds float so high up in the atmosphere that they can be seen well after dark. If present, they become visible just after sunset during the summer when illuminated by sunlight from below. Noctilucent clouds are the highest clouds known and thought to be part of polar mesospheric clouds (PMCs). PMCs are most frequently observed above 70°–75° in latitude and have a season of 60 to 80 days duration centered about a peak which occurs ~20 days after the summer solstice. This holds true for both hemispheres. Here a network of noctilucent clouds was captured two weeks ago not only in the distant sky but in reflection from a small lake just north of Zwolle, Netherlands, with trees in stark silhouette across the horizon.