What's happening over the horizon? Although the scene may appear somehow supernatural [ http://badastronomy…], nothing more unusual is occurring than a setting Sun [ http://antwrp.gsfc.…] and some well placed clouds. Pictured above are anticrepuscular rays [ http://www.sundog.c…]. To understand them, start by picturing common crepuscular rays [ http://www.ems.psu.…] that are seen any time that sunlight pours though scattered clouds. Now although sunlight indeed travels along straight lines [ http://www.theory.c…], the projections of these lines onto the spherical sky [ http://math.rice.ed…] are great circles [ http://www.maps.com…]. Therefore, the crepuscular rays [ http://www.allthesk…] from a setting (or rising) sun [ http://antwrp.gsfc.…] will appear to re-converge on the other side of the sky. At the anti-solar point 180 degrees around from the Sun [ http://antwrp.gsfc.…], they are referred to as anticrepuscular rays [ http://www.weather-…]. Pictured above is a particularly striking set of anticrepuscular rays [ http://www.gcrg.org…] photographed earlier this month from a moving car just outside of Boulder, Colorado [ http://www.state.co…], USA [ http://www.cia.gov/…].
Explanation
What's happening over the horizon? Although the scene may appear somehow supernatural [ http://badastronomy…], nothing more unusual is occurring than a setting Sun [ http://antwrp.gsfc.…] and some well placed clouds. Pictured above are anticrepuscular rays [ http://www.sundog.c…]. To understand them, start by picturing common crepuscular rays [ http://www.ems.psu.…] that are seen any time that sunlight pours though scattered clouds. Now although sunlight indeed travels along straight lines [ http://www.theory.c…], the projections of these lines onto the spherical sky [ http://math.rice.ed…] are great circles [ http://www.maps.com…]. Therefore, the crepuscular rays [ http://www.allthesk…] from a setting (or rising) sun [ http://antwrp.gsfc.…] will appear to re-converge on the other side of the sky. At the anti-solar point 180 degrees around from the Sun [ http://antwrp.gsfc.…], they are referred to as anticrepuscular rays [ http://www.weather-…]. Pictured above is a particularly striking set of anticrepuscular rays [ http://www.gcrg.org…] photographed earlier this month from a moving car just outside of Boulder, Colorado [ http://www.state.co…], USA [ http://www.cia.gov/…].
Explanation
Credit and Copyright:
John Britton [ mailto: johnbritton at computer.org ]
Credit_and_Copyright
John Britton [ mailto: johnbritton at computer.org ]
