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Super Blue Blood Moon


The other day, I woke up and I saw a spectacular total eclipse of the moon. I've seen many, but it's always stunning for me. This total lunar eclipse was even more special because of three different things happening for this eclipse of the moon, and as such it was called a "Super Blue Blood Moon." Here's why:

One, the "super" part is because the moon was at a location in its orbit where it was closest to the Earth called its Perigee. Now the moon's orbit is slightly elliptical, so it will have a perigee and an apogee, a location that is furthest from the Earth, and the moon passes through these locations once a month. The difference between the moon's distance from the Earth at perigee versus apogee is only about 11% the average distance between the Earth and the moon.

Two, the "blood" part is because during a total eclipse of the moon, the moon does turn a dark-red color. The reason is because even thought the moon is in the Earth's shadow, the atmosphere of the Earth bends red light emitted form the sun towards the moon. This is the same phenomenon that makes most sunsets appear dark-red as well.

And lastly three, the "blue" part is because this was the second full moon in the same month, which doesn't happen that often. That it is called "blue" is a misnomer because it has nothing to do with the color. In fact, the descriptor blue is actually based on an old English word "Bellue," which means to betray. So a second full moon in a month, is thought to have betrayed the standard of there only being one full moon per month.

Now there will be many total eclipses of the moon in the near future, but the next "Super Blue Blood Moon" won't happen for another 150 years.


Follow your curiosity to the Fred G. Dale Planetarium at Wayne State College.

Dr. Todd Young hails from Minnesota and received his undergraduate degree in Physics & English from the University of Minnesota – Morris, his Master’s degree in Physics from Purdue University, and his Ph.D. from the University of Nebraska – Lincoln in Astrophysics. He has worked at Wayne State College since receiving his doctorate in 1998 and is currently a full professor of physics and astronomy. He teaches a variety of courses at Wayne State College, including university physics, astronomy, general education science, and astrophysics.
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