A “Super Blue Blood Moon” is a celestial event combining three distinct lunar phenomena. This rare alignment creates a spectacular view of the Moon.
What Makes It Special
A supermoon happens when a full moon nearly coincides with the Moon’s closest approach to Earth, a point known as perigee. This proximity makes the Moon appear up to 14% larger and 30% brighter. Supermoons are relatively common, typically occurring three to four times a year.
A blue moon refers to the second full moon within a single calendar month. This definition does not mean the Moon appears blue in color. Blue moons occur because the lunar cycle is approximately 29.5 days, slightly shorter than most calendar months, leading to an extra full moon every two to three years.
The blood moon describes a total lunar eclipse, where the Moon takes on a reddish hue. This coloration happens when Earth passes directly between the Sun and the Moon, casting a shadow. Sunlight filters through Earth’s atmosphere, scattering blue light and allowing red and orange wavelengths to illuminate the Moon.
The Event of 2018
The last Super Blue Blood Moon occurred on January 31, 2018. This event was notable for combining the Moon being near its closest point to Earth (supermoon), being the second full moon of the month (blue moon), and undergoing a total lunar eclipse (blood moon).
The 2018 Super Blue Blood Moon was visible across a wide portion of the globe. Observers in North America, Alaska, and Hawaii could witness the eclipse before sunrise on January 31. Meanwhile, those in the Middle East, Asia, eastern Russia, Australia, and New Zealand experienced the event during moonrise in the evening of the same day. The western parts of the United States and Hawaii offered the most complete views of the total eclipse.
Frequency and Future
The simultaneous occurrence of a supermoon, blue moon, and total lunar eclipse is an infrequent celestial alignment. While each phenomenon happens with varying regularity, their combination is considerably rare. Some analyses suggest such an event occurs once every few decades, with estimates ranging from approximately every 37 years to about 265 years on average. The timing between these specific alignments is quite irregular.
Following the 2018 event, the next Super Blue Blood Moon is anticipated to occur on January 31, 2037. Prior to 2018, the last such event visible in the Western Hemisphere took place on March 31, 1866. For the Eastern Hemisphere, a similar alignment was observed on December 30, 1982.