A rare Super Blue Moon tonight
SHELLEY: A full Super Blue Moon will light the sky over Shelley tonight.
The full moon tonight, August 19th, will be different from other full moons that occur every 28 days because it will be a Super Blue Moon.
What is a super blue moon?
A super blue moon is simultaneously a full moon, blue moon, and a super moon.
The first of these three is pretty well known to us: a phase in the lunar cycle in which the Earth, sun, and moon are aligned with the Earth in the middle, so the moon is fully illuminated on Earth.
A blue moon is not about the moon’s color but instead the full moon’s frequency.
“There are two definitions of a blue moon—the first describes when there are two full moons in a single month. Since the moon’s cycle is 29.5 days, and our average calendar month is 30-31 days, it is incredibly rare to have two full moons in one single month, but it is possible, happening every two to three years,” according to NASA. “Around 3% of full moons are blue moons.”
There are also seasonal blue moons, in which a calendar season contains four full moons instead of the usual three, and the blue moon is the third of the four full moons. August’s full moon is of this variety. The next seasonal blue moon is expected in May 2027.
The super moon part refers to the moon’s orbit, which brings it slightly closer to Earth this month, making it appear bigger and brighter. This occurs since the moon’s orbit around the Earth is elliptical instead of just a circle, and thus there are times when the moon is further and closer to our planet.
“During the moon’s closest approach to Earth, it can appear approximately 14% larger and shine 30% brighter than when at its farthest point in the orbit,” NASA said. “This will be the first of consecutive super moons this year, and it’s less rare than the blue moon, occurring three or four times a year.”
How rare is a super blue moon?
According to NASA, the combination of the super moon and the blue moon is rare, and the time between their occurrences is quite “irregular” and could be as much as 20 years, with 10 years between the average.
