what makes a supermoon

A supermoon occurs when a full moon coincides with the Moon's closest approach to Earth in its elliptical orbit, known as perigee. This makes the moon appear larger and brighter than usual to observers on Earth. The orbit of the Moon around Earth is elliptical, so its distance varies from about 226,000 miles to 251,000 miles. When the full moon happens near the closest point (within about 90-100% of perigee), it's called a supermoon. The moon can appear up to 14% bigger and 30% brighter than when it is at its farthest point (apogee) during a micromoon. This phenomenon typically happens three to four times a year and is visually amplified by the moon illusion on the horizon.