You may have heard about the "Super Moon" that's happening tomorrow night, but do you really know what it's all about? Will the moon really look that "super"? And will this "super" full moon make people act even crazier, as the folklore says?
Well, I can't really answer the second question, but I can say, for sure, it will look bigger. In fact, the moon tomorrow night will look the biggest and brightest it's been this year - as much as 14% bigger and 30% brighter!
So why the brighter and bigger than normal moon? It's actually because of the lunar "perigee" in combination with the full moon. The moon follows an elliptical orbit around the Earth. When the moon is closest to the Earth it is called the perigee and when it's the farthest from Earth it is termed apogee.
- NASA diagram
The perigee is about 50,000 km closer than the apogee. From the image below, you can tell that during the perigee, the moon appears much bigger since it's closer to Earth. The perigee occurs at 11:34 PM tomorrow night and the full moon is a minute later. The near perfect timing brings us the bright and big super moon.
- Anthony Ayiomamitis - http://apod.nasa.gov/apod/ap071025.html
A super moon isn't all that uncommon with the full moon cycle coinciding the perigee. Last year, on March 19, 2011, we had another super moon, although it was about 400 km closer to the earth than the one we'll see tomorrow night.
I hope this doesn't spoil the novelty of the supermoon, but it will surely be a neat sight Try getting out to see the moon, as it rises. Because of the "moon illusion" , the moon will look much bigger the closer it is to the horizon. Moonrise is at 7:55 PM tomorrow night, so grab you're friends and head out for super moon gazing. Skies should be mainly clear, which will make for a bright Saturday night!
If you happen to miss the supermoon tomorrow night, here's when you can catch it through 2015. Enjoy!
- Earthsky.org - Dates of next full moon & perigee