Last August, the moon treated East Tennessee to a spectacular total solar eclipse and spurred a new generation of stargazers across the country. As if the solar eclipse wasn’t special enough, our moon is back for an encore performance of another rare event this week. During the early morning hours of Wednesday, January 31, our moon will delight skywatchers with a rare supermoon/blue moon/lunar eclipse – also known as a Super Blue Blood Moon.
What exactly is a Super Blue Blood Moon?
Let’s break it down to make sense of this amazing phenomenon.
- First, a supermoon is a full (or new) moon that occurs when the moon is at its closest proximity in orbit to earth. According to NASA, the moon will be a mere 222,068 miles from earth on Wednesday. As a result, the moon appears about 14 times larger and 30 percent brighter than a regular full moon (see image to the right – supermoon on left, regular full moon on right).
- Next, a blue moon is when two full moons occur in the same calendar month. The last full moon happened in the United States on January 1.
- Finally, a lunar eclipse is when the moon travels through the earth’s shadow. During a lunar eclipse, the moon is often referred to a blood moon because of the crimson color that appears due to sunlight being filtered through the earth’s atmosphere as it attempts to reach the moon.
Unlike the August solar eclipse when the moon passed between the earth and the sun, this time the moon will pass on the backside of the earth where the earth casts a shadow blocking the sun’s light from reaching the moon’s surface (see diagram below). As we learned in August, a total solar eclipse is only visible if you are located in the path of the moon’s shadow. However, during a lunar eclipse, all areas located in the nighttime side of the earth will be privy to this lunar eclipse.
How rare is this event?
Again, let’s break down each lunar event to get a better understanding of the rarity of the moon’s upcoming night show.
- A supermoon is the least rare of the three lunar events. Of the 12 to 13 full moons during a calendar year, about three of those are considered supermoons.
- According to the NASA website, a lunar eclipse is fairly common too. At any particular location on Earth, a lunar eclipse can occur up to three times per year while other locations may not have one.
- Have you ever heard the saying, “once in a blue moon?” That’s because blue moons are much more rare occurring about every 2.7 years. This year is particularly special because there are two blue moons in one year (both January and March have two full moons). This phenomenon is referred to as a double blue moon and only occurs three to five times per century. The next double blue moon is in 2037.
In the end, the big question is how rare is the coinciding of all three of these lunar events? Well, skywatchers, set your alarms because you don’t want to miss this one. The last time that all three events occurred simultaneously was 150 years ago. In other words, no living human has witnessed this lunar phenomenon!
When, where, and how do you witness this lunar event?
While Alaska, Hawaii, and western North America will most certainly have the best vantage point for viewing a total lunar eclipse, our area will experience a partial lunar eclipse. Along the East Coast, the lunar eclipse will begin at 5:51am when the moon enters the outer part of the earth’s shadow. The best viewing opportunity will occur around 6:48am when the darkest part of the earth’s shadow blankets the moon creating a blood-red tint.
Before you load the kids on the bus for school or head off to work yourself, I suggest finding a high place that provides a direct line of sight to the west-northwest horizon opposite of where the sunrises. The event will be short lived as the sun rises shortly thereafter, but it lasts long enough to log another astronomical event into your memory book. And, the best news….no glasses needed to view this eclipse! A lunar eclipse is completely safe to view with the naked eye.
Happy lunar eclipsing, East Tennessee!
Special thanks to Elizabeth MacTavish for explaining this phenomenal event! Elizabeth is a Clinical Assistant Professor in Science Education in the Department of Theory and Practice in Teacher Education. Prior, MacTavish taught in the Knox County school system for twelve years before completing her PhD in 2017 and beginning her position at the University of Tennessee.