MONTH

April 2021

  • April 14, 2021

V-shaped flight of migratory birds

Wednesday, April 14, 2021 When migrating long distances, migratory birds make efficient use of wingtip vortices, flying in a V-shape to conserve energy. The migratory birds are taking off nimbly through the blue sky with white clouds floating in it, looking healthy and energetic today.

  • April 12, 2021

A halo floating in the sky

Monday, April 12, 2021: I suddenly looked up and saw a ring of sunlight floating in the sky. A "sun halo," or "halo," is a solar optical phenomenon that occurs when sunlight is reflected and refracted by ice crystals that make up the clouds above, creating a ring-shaped glow.