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

The Local FluffThe stars are not alone. In the disk of our Milky Way Galaxy, about 10 percent of visible matter is in the form of gas called the interstellar medium (ISM). The ISM is not uniform and shows patchiness even near our Sun. It can be quite difficult to detect the local ISM because it is so tenuous and emits so little light. This…Read More

A Year in SunsetsA year in sunsets, from April 2023 to March 2024, track along the western horizon in these stacked panoramic views. The well-planed sequence is constructed of images recorded near the 21st day of the indicated month from the same location overlooking Cairo, Egypt. But for any location on planet Earth the yearly extreme northern…Read More