Title: אופציונלי

Text: Noctilucent clouds, or night shining clouds, are tenuous cloud-like phenomena in the upper atmosphere of Earth. When viewed from space, they are called polar mesospheric clouds (PMCs), detectable as a diffuse scattering layer of water ice crystals near the summer polar mesopause. They consist of ice crystals and from the ground are only visible during astronomical twilight. כל פסקה תהיה מבחן.

Save test: השתמש בזה אם אתה רוצה לשתף את המבחן הזה בהקלדה (רק למשתמשים מאומתים).