THE SUPERMOON IS UPON US! The biggest full Moon of the year will be lighting up the night sky Saturday night. Find out what makes this Moon different, and what, if anything, you need to look out for. (Werewolves? Tidal waves?? YOU CAN NEVER BE TOO CAREFUL, PEOPLE.)
So what makes Saturday night's Moon a SUPERmoon? Four things:
1. As of 11:35 p.m. EST, the moon will officially be completely full.
2. This full Moon happens to coincide with the Moon's closest approach to the Earth for the month, an event astronomers refer to as "perigee."
3. This month's perigee will actually be the closest to Earth in all of 2012 (some perigees are closer than others), making this Moon a super-supermoon!
4. Unrelenting media coverage.
The opposite of perigee is apogee. These monthly variations in the Moon's distance from Earth stem from the fact that our satellite's orbit is not perfectly circular, but elliptical. The effects of this orbit on the apparent size of the Moon can be seen in the animation featured here. (The rocking motion that you see is something that astronomers call libration, and has to do with the varying speed of the Moon's orbit.)
ANYWAY. What does all of this mean for you? Believe it or not, almost nothing. Will today's ocean tides be higher and lower than usual? Yes, but not by much; your odds of getting crushed by a tidal wave are about equal to your chances of spotting a werewolf, which is to say: practically zilch. (Unless you're from Wisconsin, in which case your odds of spotting a werewolf are a little higher than that whole tidal wave scenario.)
Will the Moon be bigger and brighter than any other point in the year? Again, yes — but unless you're comparing photographs like these, you probably won't actually be able to tell the difference with your naked eye. As NASA explained in the lead-up to last year's supermoon (which, by the way, was the largest supermoon in close to two decades): "there are no rulers floating in the sky to measure lunar diameters. Hanging high overhead with no reference points to provide a sense of scale, one full Moon can seem much like any other."
In brief: if it weren't for people telling you that Saturday's Moon would be special, you probably wouldn't have noticed, anyway.
Be that as it may, don't let that prevent you from getting outside to catch a glimpse, anyway — the Moon is (and always has been) very beautiful, after all. Plus, it is a lot of fun to say SUPERMOON. And nobody can take that away from you.