August’s lunar fanfare ends with a treat: a blue supermoon that will occur Wednesday at 9:36 p.m. Eastern time.
The blue moon is the second of two full moons in one month. Each month usually hosts just one full moon, but blue moons sometimes occur because the lunar cycle lasts 29.5 days — just a little shorter than the length of an average calendar month. This difference means that there are two full moons in some months.
That’s exactly what will happen in August: the first full moon appeared on August 1, and the second came on the evening of August 30.
What is a Blue Supermoon?
A supermoon occurs when the full moon phase of the lunar cycle is in sync with perigee, or when it is closest to Earth. Supermoons appear brighter and larger than regular full moons. According to NASA, the apparent size increase is 14 percent, which is about the difference between a nickel and a quarter.
Supermoons are generally seen every three or four months. This will be the third this year and the second in August. Blue moons, on the other hand, only occur once every two or three years (hence the phrase “once in a blue moon”). Blue supermoons are even more rare, occurring about once every ten years. The last was in 2018 during a lunar eclipse, and the next blue supermoons will appear as a pair in 2037.
Will the moon really look blue?
No. The term “blue moon” doesn’t really describe its color, and the moon will usually be the usual milky gray color. (Certain phenomena, such as wildfires and volcanic eruptions, can turn the moon blue, the same visual effect that gave the North American sky an orange hue this summer.)
According to NASA, the term “blue moon” referred to the third full moon in a season with four full moons. The newer definition – the second full moon in a month – was coined in 1946 by Sky & Telescope magazine.
How can I see it?
Unlike some other celestial events, everyone on Earth sees the same phases of the lunar cycle at night, so the blue supermoon will be visible everywhere. That means all you have to do is look to the night sky to see it. NASA recommends using binoculars or a telescope to see more of the moon’s texture.
In the United States, the moon appears full on Tuesday, Wednesday and Thursday nights. Wednesday evening you may also see a bright dot on the upper right of the moon. That’s Saturn, a few days away from reaching its closest point to Earth. The ringed planet orbits the moon clockwise at night.
