A supermoon is simply a full moon that appears unusually large and bright because the Moon is at its closest point to Earth in its elliptical orbit (perigee) at the same time as the full Moon. Key points:

• Perigee: The Moon’s closest approach to Earth in its roughly 27-day orbit. When the full Moon coincides with this closest point, it can look noticeably larger and brighter than a typical full Moon.

• Full Moon phase: The Moon must be in its full phase for the intensity of illumination to be at its peak, which complements the closer distance to Earth.

• Not officially official: “Supermoon” is a popular term rather than a formal astronomical classification, but it’s commonly used to describe this combination of full Moon and near-perigee.

• Typical frequency: The phenomenon occurs a few times a year, but exact distance varies because the Moon’s orbit is slightly elliptical and influenced by gravitational forces from the Earth and Sun.

Simple explanation:

• When the full Moon happens near its closest approach to Earth, the Moon looks bigger and brighter than usual. That combination defines a supermoon.

If you’d like, I can pull a few current sources or provide a quick comparison of recent supermoon dates and how close the Moon gets to Earth during those events.