Physics Photo of the Week

Physics Photo of the Week September 22, 2023 Sun Halo over the Arizona Desert - Photos by Dr. Betsy Arnold, University of Arizona Warren Wilson Professor Dr. Amy Boyd and her research colleagues: Margrit McIntosh, Betsy Arnold, and Lucinda McDade (director of the California Botanic Garden) were  observing environmental parameters near Tucson, Arizona when they noticed this magnificent atmospheric halo visible above the desert.  Lucinda McDade can be seen in the  photo making observations of desert plants.  Click on the photo and n otice the ruler next to the rock on her right side - one of several tools being used.   Regarding the ongoing research in the desert of Arizona Dr Boyd writes: Several of us (Amy Boyd, Margrit McIntosh, Betsy Arnold and Lucinda McDade) study the population biology of an endangered Sonoran Desert cactus, the Nichol's Turk's head cactus, Echinocactus horizonthalonius var. nicholii , in the Waterman Mountains of Arizona.  We've been studying the

 Orion in August - Photo by Donald Collins   Orion the Hunter is a well-known constellation of bright stars that is very vivid in January.  It is known as a "winter constellation" because it is usually seen in the winter months.  Clicking on the image shows a larger image with the constellation shape outlined. This image was made from Willoughby Lake in Vermont about 2 1/2 weeks ago on August 23, 2023.   How can we see the familiar winter constellation in the summer?  Is it due to the location on Earth and the view of the sky from a more northern location?  Is it due to the time of night that the sky was viewed?  Or, is it due to the phase of the Moon? The answer is the second choice: the time of night that the photograph was made.  I had gotten up at 5 am and took this photo when the air was extremely clear in the pre-dawn sky.  The stars are at vast distances from the Earth and the Solar System.  As the Earth orbits the Sun within the Solar System, the constellations and st