To me, every moon is a super moon. I mean, how lucky are we to have the fifth largest moon in the whole solar system? It's beautiful in all of its phases, be it the waning crescent or the waxing gibbous. (See moon phases animation on the right!) So what's all the flap about the full moon coming up on Sunday? What makes that full moon a "super moon"?
The super moon is a recent term used to describe a full moon that occurs at the time that the moon is closest to the Earth in its orbit. The moon appears larger and brighter because of this.
Take a look at the diagram to the right. Notice that the orbit of the moon is NOT a perfect circle, but is more oval-shaped (though exaggerated in this drawing). Astronomers describe this as an "elliptical" orbit. Because of this, the moon will sometimes be farther away from the Earth (apogee) and sometimes it will be closer to the Earth (perigee). A trick to remember this: think that the "a" in "apogee" means "away."
If the full moon happens to occur around the time of the perigee, you have a SUPER MOON! Think about it: things look bigger when they are closer.
NASA scientists tell us to expect a 14% larger, and 30% brighter full moon this Sunday. Expect higher high tides and lower low tides, as the gravitational pull increases as the distance between the Earth and the moon gets smaller. But most of all, just go out and gaze at our most beautiful neighbor in space. I promise you it's something to moon over.
By NASA/Goddard Space Flight Center Scientific Visualization Studio [Public domain], via Wikimedia Commons
welcomes you to visit with the all the wonderful flora and fauna that we share this lovely aina with.