Cosmic ballet spins up rare "super blue blood moon" this week
A cosmic trifecta will occur this Wednesday, January 31, when some parts of the planet will see not just a super moon, a blue moon or a blood moon, but a super blue blood moon. A combination of events that last occurred 152 years ago, it will be best seen in the early hours before dawn across North America and the Pacific Ocean region.
We talk about something happening once in a blue moon, but it's more than just a turn of phrase. Blue moon's are real, but they don't have anything to do with the color of our satellite. Instead, it refers to the second full moon within the same month – an event that occurs once every 2.7 years.
It's called a blue moon due to a convoluted evolution from the Tudor era, when it meant something absurd, like thinking that the Moon is actually blue, before becoming slang for something that is rare, and eventually to its present astronomical meaning of two full moons in a month – as is the case here – or the third of four in a season.
Less rare are supermoons, which happen four to six times a year. A supermoon is when a full moon coincides with the time when the Moon is closest to the Earth. When this happens, the Moon appears larger and brighter than normal – Wednesday's will appear about 14 percent brighter than usual.
Also not as rare is a blood moon, which sounds ghastly, but simply refers to when a total eclipse of the Moon happens. When the Moon moves completely into the Earth's shadow, the refracted light turns it dark red. If you keep careful watch on the night sky, you should see one at your location four or five times every decade.
But what is rare is having all three of these events happen at the same time. That's like hitting 13 black on the roulette wheel three times running. the last time that happened (the Moon thing, not the roulette) was on March 31, 1866 and there won't be another super blue blood moon until December 31, 2028.
If you're interested in seeing the event, the eclipse is best observed in the Pacific region, where it can be viewed from Alaska to Australia and East Asia in its entirety in the hours before sunrise and moonset.
It will be barely visible on the North American east coast beginning at 5:51 AM EST, which is as dawn begins to break, but it will be seen better across the northern regions as one travels westward, with totality beginning at 6:48 am EST and ending at 9:05 am.
If you're not in a viewing region for the eclipse, NASA will transmit it live on on January 31 at 5:30 am EST on NASA TV and NASA.gov/live.
The video below gives an overview of the lunar trifecta.