We often hear that a particular full moon is a “supermoon”, but what does that mean? And what is a “micromoon”?
“Super” Full Moon
A supermoon is a full moon occurring at perigee, the moon’s closest point to Earth in its orbit. A supermoon can appear up to 14% bigger and 30% brighter than a “micromoon”, or 7% bigger than an average full moon.
As previously mentioned, the difference in size and brightness is due to the moon’s proximity to Earth. We often think of the moon orbiting around the Earth in a perfect circle, but the reality is that the orbit is more elliptical in nature. As a result, the moon can be as “close” as 225,310 miles from Earth during perigee — this is known as a “supermoon”.
“Micro” Full Moon
On the other side of the orbit, the moon is 251,904 miles away from Earth — this is apogee, and the moon looks smaller (hence the nickname “micromoon”).
We don’t tend to hear of micromoons very often (compared to supermoons), but the next micromoon will occur on September 13, 2019.