Astronomy Picture of the Day

Explanation: The dark, inner shadow of planet Earthis called the umbra.Shaped like a cone extending into space, it has acircular cross section most easily seen during alunareclipse.And on the night of September 7/8 theFull Moon passednear the center of Earth's umbral cone,entertainingeclipse watchers around much of our fair planet,including parts of Antarctica, Australia, Asia, Europe, and Africa.Recorded from Zhangjiakou City, China,this timelapse composite image usessuccessive pictures fromthe total lunar eclipse,progressing left to right, to reveal the curved cross-section of theumbral shadow sliding across the Moon.Sunlight scattered by the atmosphere into Earth's umbracauses the lunar surface to appear reddened during totality.But close to the umbra's edge, the limb of the eclipsed Moon shows adistinct blue hue.The blue eclipsedmoonlight originates as rays of sunlightpass through layers high in the upper stratosphere,colored by ozone that scatters red light and transmits blue.In the total phase of thisleisurely lunar eclipse,the Moon was completely within the Earth's umbra for about 83 minutes.