Super Blue Blood Moon? What is That?

Tomorrow morning, much of the U.S. will wake up with a bright red moon. But why is it called a super blue red moon, and what causes it? Three facts contribute to this. How often a full moon occurs in one month, the distance a full moon is from the Earth, and a total lunar eclipse.

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Normally, we will experience a full moon approximately once each month. There are occasions, however, where we will experience a full moon twice in one month. This previously occurred in 2015 and will again happen both in January and March of this year. Such an occurrence won't happen for another 19 years (Ciaccia, 2018).

Supermoons occur when the moon reaches a perigee of approximately 223,068 miles from the Earth. As the moon orbits in an elliptical path, it's distance from the Earth increases and decreases depending on whether it has reached an apogee (farthest from Earth) or perigee (closest to Earth). During a supermoon, it will appear "up to 14% larger and 30% brighter than" it normally would (McCarthy, 2018). For most people, this size difference is not noticeable to the common eye which sometimes causes confusion.

The Blood moon effect is caused by a total lunar eclipse which occurs when the Earth comes between the Sun and the Moon. As light passes through the atmosphere, the blue spectrum is filtered from the rest of the light ray causing a red appearance during the eclipse.

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But wait!!! This does not explain the blue moon name! It seems there were several occurrences when the moon actually turned blue. The volcano Krakatoa exploded in 1883 which caused dust to turn the sunset green and the moon blue for two years. In 1927, India experienced a long dry season due to the late arrival of monsoons. Blown dust once again caused the moon to appear blue. When Canada experienced forest fires in 1951, smoke particles again caused the moon to turn blue (Hiscock, 2012). Since such occurrences appeared so rare, the term "once in a blue moon" developed.

So if you get up early enough, I hope you have a chance to see this rare beauty. If you do, I hope you will share some photos if you take any. Get a good night sleep, get up early, and enjoy the sight.