October 16 is the first night of the year when there will not only be a full moon in the night sky, but it will also be at its closest point to Earth, making it a ‘supermoon’.
The term, according to NASA, was originally given to a new or full moon that occurs when the moon is “within 90 percent of its closest approach to Earth in a given orbit”, but it’s now used more broadly to cover any full moon that is closer to Earth than normal.
The moon’s distance from Earth varies depending on which side of its journey the moon is on during its elliptical orbit. ‘Perigee’ is about 30,000 miles closer to Earth than the opposite side ‘Apogee’.
When the Earth, sun and moon line up during the ‘perigee’ side of the lunar orbit, we get a ‘perigee moon’ or ‘supermoon’.
Perigee full moons can appear up to 14 percent bigger and 30 brighter than apogee full moons, and often create the optical illusion of a ‘low-hanging’ moon.
After October, the next supermoons to round off the lunar hat-trick will appear on November 14 and December 14.
November’s date is expected to reach “extra-supermoon” status as it becomes a full moon within about two hours of perigee, making it the closest full moon of the 21st century.
The extra-supermoon phenomenon won’t be witnessed again until November 25, 2034.