Of course, the moon doesn't actually change size, but it appears to be larger because of how its orbit lines up with the Earth and sun.
Supermoons occur because of the shape of the moon's orbit around Earth.
Nasa described the event as the first in a "supermoon trilogy", with two more to come on January 1 and January 31. However, a brighter moon is the effect of an illusion caused by the close location of the moon, which makes the human brain compare it to nearby objects. It appeared about seven per cent larger and 15 per cent brighter.
Part of it depends on where you're viewing the supermoon.
A supermoon rises in front of a replica of the Statue of Liberty sitting atop the Liberty Building in downtown Buffalo, N.Y., Sunday, Dec. 3, 2017.
Gunmen attack agriculture institute in Pakistan, killing 12
Three burqa-clad gun men have also entered the Directorate as intermittent gunfire, and blast heard from inside the premises. Peshawar , close to the Afghan border, has seen some of the worst violence during the Taliban insurgency in recent years.
Supermoon rising, December 2.
The time between perigees (an anomalistic month, about 27.555 days) does not align very well with the time between full moons (a synodic month, about 29.531 days). The supermoons seem 14% bigger and 30% brighter than the normal full moons.
The final supermoon of 2018 will occur just a few weeks later, on January 31, with extra superlatives.
Clear skies across most of New Zealand made for great viewing conditions, with many would-be astronomers climbing Auckland's volcanoes to get the flawless shot as the moon rose over the horizon just before 9pm. A Blue supermoon is said to occur when two full moons occur in the same month.