The blood moon brought many star gazers out late Monday and early Tuesday. At 9:53 p.m. PT, the Earth began to position itself between the sun and the moon for the first of a series of four total eclipses to conclude in September 2015.
The phenomenon is known as a tetrad, in which the moon is completely covered by the earth’s umbral shadow for four eclipses in a row, as opposed to only partial eclipses that fall in the outer penumbra.
But rather than succumbing to complete darkness, the moon glows red as it receives the refracted light that spills over the Earth’s circumference.
The series is a rare occurrence in history, with large spans of time, such as the 300 years between 1600 and 1900, witnessing none. But the 21st century will be more promising, according to Fred Espenak, who works for NASA's Goddard Space Flight Center and specializes in eclipse predictions.
“Frequency sort of goes through 585-year cycles,” the astrophysicist explains. “So you go through centuries where you don’t have any, and centuries where you have a number of them.”
The next tetrad will begin in 2032.