Physics Photo of the Week

Physics Photo of the Week March 22, 2024   M42 - The Great Nebula in Orion - Astrophotos by College View Observatory The Orion Nebula - Messier 42 - is the brightest nebulous object in the sky - even visible with the naked eye in dark skies.  If this looks like a large cosmic cloud lit up from the inside - that's exactly what it is!  This cloud is in the Milky Way galaxy - "only" about 1300 light years distant.  This nebula is relatively close.  The closest external galaxy is about 2 Million light years distant - over 1000 times further away.  The colors and the large angular size (greater than one degree) make the Orion Nebula one of the most beautiful and interesting cosmic objects! The interior light for illuminating this gigantic cosmic cloud is a nursery of "baby" stars in the middle of it.  However the "baby" stars are not "innocent".  They are some of the hottest stars known in the cosmos as well as some of the largest.* The photo at

Physics Photo of the Week March 8, 2024 The Sun I photographe d this image of the Sun recently (Feb 26, 2024) using a 4-inch (104 mm aperture) telescope fitted with a special solar filter and a digital SLR camera.  The solar filter has a transmission of 1/100,000 amount of the incident light.  The solar filter also reddens the image.  Since the Sun's surface, or photosphere , has a temperature of about 5700 deg K, its true color is blue white - about the color of old-fashioned fluorescent light tubes. Notice the large sunspot dominating a group of sunspots on the center right of the Sun's image.  The Earth is only about 1/100 the diameter of the Sun, smaller than the size of the large sunspot.  Sunspots are cooler regions of the Sun's surface (about 2000 deg K cooler than the surrounding photosphere).  Sunspots are also known for strong magnetic fields directed out of the sunspots.  Thus a sunspot  resembles the north pole or south pole of a strong magnet.  This strong magn