The moon's path around the earth is not a perfect circle. As a result, it is closer at times and farther at others from the earth.
When it is at its closest to earth, it is a point we call "perigee". Conversely, when it is at its farthest point from earth, we call it "apogee."
When at perigee, a full moon will actually be noticeably bigger than usual. The following image shows a "usual" full moon (left) in comparison with a perigee full moon (right).
When the moon is a bit closer, it also results in higher-than-normal high tides and lower-than-normal low tides.
The full moon that coincides with the point of perigee is called a "Super Moon".
2012's super moon is on May 5th. The moon will only be 356,955km from the earth, about 30,000km closer than the annual average distance from earth to the moon (384,400km).
For more, watch the video attached to this story.
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