A "super blue moon" is a rare astronomical event combining two phenomena:
- Supermoon: This occurs when a full moon happens near the Moon's closest point to Earth in its elliptical orbit, called perigee. Because the Moon is closer, it appears up to 14% larger and brighter than a typical full moon
- Blue moon: This term has two common meanings. The most popular is the second full moon in a single calendar month, which happens every two to three years. Another definition is the third full moon in a season that has four full moons instead of the usual three. The Moon does not actually appear blue during a blue moon; the name just signifies rarity
When these two events coincide—a full moon that is both a supermoon and a blue moon—it is called a super blue moon. This is quite uncommon, occurring roughly once every 10 years on average
. Despite the name, the Moon will not look dramatically bigger or blue to the naked eye, but it will be slightly larger and brighter than a normal full moon
. In summary, a super blue moon is a full moon that is both unusually close to Earth (supermoon) and is the second full moon in a month or the third in a four-full-moon season (blue moon), making it a rare and interesting event to observe
