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...

 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 w...

 

Cumulus Clouds - Photos by Donald Collins   C umulus clouds are the most familiar and most common cloud formations.  Their formation is very simple: these clouds form on sunny days and result from air that has been heated by the Sun; the heated air rises to higher elevations because the heated air has expanded and has a lower density, so it rises like air bubbles in water.  In rising to higher elevations the surrounding atmospheric pressure is reduced and the air expands.  Air bubbles or carbon dioxide bubbles rising in a carbonated beverage do a similar expansion.  A "bubble" of expanding warm air - up to several hundred meters in diameter - is "insulated" from the temperature of the surrounding air because of its sheer size.  This is in contrast to the tiny bubbles rising in a beverage glass that have intimate thermal contact with the surrounding water-based beverage. When a parcel of air that is insulated from it's environment expands, its temperature l...

  Cumulus growth from Willoughby Lake  Click on READ MORE to see animation

Cumulus growth from Warren Wilson Press READ MORE to view animation

  M87 - Elliptical Galaxy in Virgo: Special properties Photo by College View Observatory The object (M87) in this photo is a distant galaxy - about 50 million light years distant - a galaxy of many billions of stars within the constellation Virgo.  At first glance it resembles a "blob" - more resembling a comet without a tail than a galaxy.   Many galaxies are much more photogenic showing grand spirals, dust lanes, and other interesting structures.  M87 is a class of galaxies called  elliptical galaxies. This elliptical galaxy is also rather ordinary in first appearance in that it appears spherical rather than a football-shaped ellipsoid.  Just a "blob" of stars without any noticeable structure unlike the Andromeda Galaxy (see PPOW for Jan. 18, 2019) . However, upon close inspection of the photograph, seen much clearer in a zoomed-in photo at right, there is an apparent "jet" or ray of light made much more visible by cropping the above image and enlar...