Enough with the “Super Moon” already!
The Moon’s orbit is not perfectly circular; like most planets and moons, its orbit is slightly elliptical. An ellipse is a stretched-out circle (in case you don’t remember your days in high school geometry). The distance between Earth and the Moon increases and decreases during the course of the Moon’s orbit.
The average distance is about 384,000 kilometers (that’s KIL-o-me-ters, not kil-AH-me-ters!) but the Moon can get as close as 362,570 kilometers and as far away as 405,410 kilometers. When the Moon is at its closest point to Earth, we say that it has reached perigee. When it is farthest away from Earth, it has reached apogee.
Now let’s go even farther back in your schooling. Surely you remember that the Moon goes through a cycle of phases as it moves around Earth…right? That’s because we see different portions of its surface lit up by the Sun. The full moon happens when the Sun, Earth, and Moon are roughly aligned, and we see almost all of the Moon’s Earthward face lit up by sunlight. The full moon coincides with the lunar perigee about once a year, and that’s when we have a so-called Super Moon.
Let’s be clear: the phrase “Super Moon” is not used by astronomers. It actually has more to do with astrology, which is about as far removed from modern astronomy as you can get. Also, while the Super Moon might look a bit larger and brighter, most people will not be able to tell the difference. The picture in this meme is entirely misleading.
And Super Moons are not all that rare. As I pointed out before, there’s roughly one Super Moon every year, and they’re nothing to get worked up over. Also, the Moon passes through its perigee once every orbit (which takes approximately one month to complete), so it’s misleading to say that the Moon hasn’t been this close to Earth in a long time…unless you consider a month a long time.
Go out and look at the Moon if it pleases you, but don’t expect a dramatic display. Chances are you won’t be able to tell the difference between the Super Moon and any other full moon. There: consider your party pooped.