What is Supermoon?
- Supermoon or perigee full moon is a phenomenon that occurs when a full moon coincides with the moon being the closest to the Earth on its orbit.
- During this time, the natural satellite appears roughly 30% larger in area and 30% brighter than the smallest full moons.
- In terms of diameter, the width of the moon is about 14% wider than the smallest full moons.
What causes a Supermoon?
- The moon’s orbit around Earth is ellipse (a kind of squashed circle) and not in a circle.
- When an orbit is elliptical, Earth in the middle sits at one of two foci of ellipse.
- The moon is inevitably closer to the Earth when it passes one side of the ellipse and further away as it passes the other side.
- When it is at the closest side (called “perigee”) it is a full moon.
- If this distance is to closer to earth then it is called a supermoon.
Why are supermoons not all the same size?
The reason is that the shape of the ellipse that the moon draws around the Earth is changing all the time as it is pushed and pulled by other gravitational forces.
