June 27, 2016
Even the most precise clock in the world cannot measure how unlikely your existence really is.
Anticrepuscular Rays over Colorado (II)
Birthday · June 27, 2016
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APOD published June 27, 2016. Credit: Regina Kelly. A publication-date match, not a photo taken on your date. Independent of NASA.
What's happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds. Now although sunlight indeed travels along straight lines, the projections of these lines onto the spherical sky are great circles. Therefore, the crepuscular rays from a setting (or rising) sun will appear to re-converge on the other side of the sky. At the anti-solar point 180 degrees around from the Sun, they are referred to as anticrepuscular rays. Featured here is a particularly striking display of anticrepuscular rays photographed earlier this month in Westminster, Colorado, USA. Deja vu: Anticrepuscular Rays over Colorado (I)
Image credit: Regina Kelly