Physics Photo of the Week

Clouds and Sunshine on Groundhog Day Photos by Donald Collins  On Groundhog Day (Feb. 2, 2024) we had nice, sunny weather with a few clouds.  The groundhog must have seen his shadow because we have had continuing cold temperatures - but no snow - for the beginning of the second half of the season.  Groundhog Day historically was chosen to occur approximately halfway between the winter solstice and the spring equinox. I had been examining the weather satellite photos (from https://weather.ndc.nasa.gov/GOES/ ) and noticed the wave-like clouds in the area northeast of my location near Warren Wilson College - the 'X' in the image (right) in western North Carolina.  These wave clouds are quite fascinating, so I grabbed my camera and looked from my deck in the direction of the clouds northeast of our house to photograph the Groundhog Day clouds in the top photo. Since clouds are dynamic - always moving - cloud photos are much more interesting if we take time-lapse photos...

  February 9, 2024 The Owl Nebula - and other planetary nebulae Photos by Donald Collins - College View Observatory   If we look with a telescope with some skill we can view the Warren Wilson College's mascot looking down on us.  The Owl Nebula is a class of nebulae that are called " Planetary Nebulae ".  Planetary nebulae are the remnants of dying stars.  A star like our Sun, when its hydrogen fuel is used up by fusing into helium, the resulting lack of internal radiation pressure allows the star to shrink by its self-gravity.  However, while shrinking, the core of the star becomes dense enough and hot enough for helium gas to ignite from nuclear fusion to form even heavier elements (carbon, oxygen,etc).  This second ignition blows away the outer portions of the progenitor star into an expanding cloud that we can see with telescopes. Planetary nebulae have nothing to do with planets.  The name originates because primitive telescopes ...