WWT Supermoon by David Reynolds

The Science behind a Supermoon

Today, November 14, marks an extraordinary Supermoon. The last time the Moon was this close to Earth was January 1948. And according to a statement from NASA, the next time the Moon will be this close to Earth will be in November 2034. A Full Supermoon looks nearly 7% larger than your average Full Moon due to the proximity to Earth.

WWT Supermoon by David ReynoldsThe Moon orbits the Earth in approximately 29.5 days. The various locations of the Moon in orbit describe each phase of the lunar cycle. A Full Moon occurs when the Moon is on the opposite side of Earth from the Sun. Consequently a new Moon emerges when the Moon passes between the Earth and the Sun.

What some might not know is that the Moon’s orbit is an ellipse… not a perfect circle. On average, the moon orbits close to 230,000 miles from Earth. However, there are numerous gravitational forces pulling and pushing on the Moon throughout its orbit, therefore, the distance from the Earth to the Moon varies day to day. The Moon is at perigee when the Moon is closest to Earth. Scientists describe the Moon’s furthest point from the Earth as apogee. The term Supermoon was coined by author Richard Noelle in 1979 for an issue in Dell horoscope Magazine. Noelle defines a Supermoon as “a Full Moon occurring when the Moon is at or near (within 90% of) it’s closest approach to Earth (perigee)”.

The end of 2016 has been marked by several Supermoons. If you missed the opportunity last night, be sure to catch the next (and last Supermoon of 2016) on December 14.