PHOENIX - Keep your eye on the sky in January for a rare treat: A Super Blue Blood Moon.
According to NASA, the Full Cold Moon in December kicked off a “supermoon trilogy,” and you won’t want to miss the third installment.
But first, we get a little appetizer on New Year’s Day, when the first supermoon of 2018 appears.
Then we get the extra special supermoon on Jan. 31. NASA says that supermoon will also be a Blue Moon and occur during a total lunar eclipse.
No, that doesn’t make it a purple moon. A Blue Moon occurs when two full moons fall within the same month; the name has nothing to do with its color. A Blue Moon happens about once in 2.7 years, according to Space.com.
During a lunar eclipse, the moon moves into Earth’s shadow, so the only light reaching the moon’s surface is reflected off the Earth’s atmosphere.
The same mechanism that makes the sky blue and gives us red hues in sunrises and sunsets gives the moon its red color during a lunar eclipse — a process called Rayleigh scattering. Of visible light waves, red light waves are scattered the least by atmospheric molecules.
So as the sun’s light travels through Earth’s atmosphere toward the moon’s surface, it appears red, thus the name Blood Moon.
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