Spectacular Copper Harbor Sunset

November 18, 2009


Photographer: S. I. Smith
Summary Authors: S. I. Smith; Jim Foster

November 2009 Earth Science Picture of the Day Viewer's ChoiceThe photo above showing a spectacular sanguine sunset was taken from Copper Harbor, Michigan on October 4, 2008, at 8:00 p.m. I had my back to the Sun and suddenly noticed that the entire atmosphere, including both sky and landscape, seemed to be glowing red. I looked behind me, caught my breath, and then dashed for my camera. Evidently, there was an exceptional amount of aerosols in the atmosphere on this early autumn day. The greater the number of particles in the atmosphere, the greater the scattering and absorption, and thus less light is transmitted. When the Sun is near the horizon, and if the air is quite clean, about 1/3 of red light and only about 1/100,000 of violet light reaches the surface. Once the Sun is below the horizon, the atmosphere is aerosol rich and mid- and high-altitude clouds cover much of the sky, twilight is rendered in shades of scarlet and crimson. Note that because of its location in the extreme western portion of the Eastern Time Zone, sunsets occur quite late at Copper Harbor – over an hour later than in Boston, which is in the same time zone.