This year's biggest "Supermoon"...The distance between the moon and the earth is the shortest.

This year's biggest and roundest month, 'Supermoon,' has surfaced in the night sky.

This is the third supermoon this year, after March 10 and September 17, and it is the largest and brightest of the three supermoon times.

The Gwacheon National Science Museum said the distance is different every time because the moon orbits the Earth in an elliptical orbit, and that the distance between the Earth and the moon overnight is 367,173km, the closest this year.

Supermoons appear about 14 percent bigger and 30 percent brighter than 'minimoons' passing through the most distant points, when they are full or old, while the moon passes through points close to Earth.