Planet Earth at TwilightNo sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual transition to darkness we experience as twilight. With the Sun illuminating the scene from the right, the cloud tops…Read More

Grand Spiral NGC 5643Viewed face-on, grand spiral galaxy NGC 5643 has a festive appearance in this colorful cosmic portrait. Some 55 million light-years distant, the galaxy extends for over 100,000 light-years, seen within the boundaries of the southern constellation Lupus. Its inner 40,000 light-years are shown in sharp detail in this composite…Read More

Diamond Dust Sky EyeWhy is there a huge eye in the sky? Diamond dust. That is an informal term for small ice crystals that form in the air and flitter to the ground. Because these crystals are geometrically shaped, they can together reflect light from the Sun or Moon to your eyes in a systematic way, causing huge halos and unusual arcs to appear.…Read More

Fox Fur, Cone, and Christmas TreeWhat do the following things have in common: a cone, the fur of a fox, and a Christmas tree? Answer: they all occur in the constellation of the Unicorn (Monoceros). Considered as a star forming region and cataloged as NGC 2264, the complex jumble of cosmic gas and dust is about 2,700 light-years distant and mixes…Read More

Christmas Tree AuroraIt was December and the sky lit up like a Christmas tree. Shimmering, the vivid green, blue, and purple auroral colors that formed the tree-like apparition were caused by high atmospheric oxygen and nitrogen reacting to a burst of incoming electrons. Collisions caused the orbital electrons of atoms and molecules to jump into…Read More