This composite image shows a sequence, from bottom left to top left, of the moon's transition during a total lunar eclipse on April 15, 2014 in Miami, Florida. People in most of north and south America should be able to witness this year's first total lunar eclipse, which will cause a “blood moon” and is the first of four in a rare Tetrad of eclipses over the next two years. (Photo by Joe Raedle/Getty Images)

A total lunar eclipse is seen through the old city walls on June 15, 2011 in Jerusalem, Israel. The longest lunar eclipse for a decade took place tonight. A lunar eclipse comes when the sun, Earth and moon line up and Earth's shadow falls on the moon. (Photo by Uriel Sinai/Getty Images)