Rare 'Blood Moon' Lunar Eclipse(ABC News) -- Last night provided a spectacular view of the “blood moon.” It was just the first of a series of four total eclipses that will conclude in September 2015.
By: Elizabeth Gonzalez , ABC News
(ABC News) -- Last night provided a spectacular view of the “blood moon.” It was just the first of a series of four total eclipses that will 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 will glow 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.
Other factors add to the singularity of this year’s event. For one, North America will have front-row seats to the show, not always a guarantee. It just so happens that this part of the western hemisphere, along with some of South America, will align perfectly with the cast shadow. The rest of the world, on the other hand, will experience partial visibility or none at all.