In an astronomical event not seen for over 150 years, we’ll see a blue moon, supermoon, and lunar eclipse at the same time on January 31.
A Once In A Lifetime Event
Despite the misleading name, a blue moon has nothing to do with color. Blue moon is simply a common term used to refer to the second full moon in a single month.
We kicked off the New Year with a “wolf full moon,” named for the howled of wolves in winter. The moon on January 1st was also a supermoon, and Space.com reports that it’s also the brightest moon we’ll see all year.
The blue moon of this month will fall on the last day, just barely squeezing into January and making the month a rather rare example of two full moons within the same month. This occurrence on its own isn’t nearly as rare as the blue moon, supermoon, and lunar eclipse combination we’ll see at the same time – rather, occurring around once every two and a half years. 2018 will be special, however, with a second blue moon on March 31st of this year.
NASA has called the phenomenon coming on January 31st the end of a “supermoon trilogy.” A supermoon is when the full moon occurs alongside the “perigee” of the lunar orbit. Basically, because the moon’s orbit is an ellipse rather than a perfect circle, there are times when it’s somewhat closer to Earth than usual. A supermoon refers to the larger appearance, looking around 14 percent bigger and 30 percent brighter than the point in its orbit when it’s farthest away from Earth.
The blue moon, supermoon, and lunar eclipse event won’t shine quite as bright as the full moon we saw on New Year’s Day, but will instead offer something far more fascinating – a reddish color from a total lunar eclipse. The combination of a supermoon and lunar eclipse will result in a visually striking moon that is the largest we see in orbit, so you should make sure to step outside at night on the 31st – just remember to wear a jacket!
Viewing The Blue Blood Moon
Unfortunately, the total lunar eclipse will only be visible by select U.S-based viewers. But for those of us who will be able to see it, we’ll be treated to a red glow as the Earth sits directly between the sun and moon. This perfect lineup causes the sun’s light to filter through Earth’s atmosphere which causes a normally-bright moon to have a red surface. This occurrence is also known as “blood moon,” based on the reddish hue.
The “blue blood moon” will be visible mostly in Alaska, Hawaii, and select parts of the western U.S. For watchers in order parts of the mainland U.S., only a partial eclipse will be visible.
Noah Petro, a research scientist based at NASA’s Goddard Space Flight Center gave some advice on how best to view the blue moon on the agency’s website:
“The lunar eclipse on January 31 will be visible during moonset. Folks in the eastern United States, where the eclipse will be partial, will have to get up in the morning to see it…But it’s another great chance to watch the moon.”
As mentioned above, the coincidence of a blue moon and blood moon is a once in a lifetime event. While the rate of occurrence does vary, chances are that we’ll never get another chance to see this astronomical spectacle. The field of astronomy has advanced a lot in the past 150 years so it may be easier for us to predict these events moving into the future, but the workings of the universe move on a much slower schedule. Our awareness of the world around us has never been better, but we’re largely at the mercy of our solar system when it comes to viewing opportunities such as these.
The impact of the view will vary based on where you’re located, and this phenomenon will be most appreciated by those in the western United States, but it’s still worth taking a step outside and taking a look at the spectacular “blue blood moon.”