Supermoon .. or not?

by Tanya
Publish date
23 June 2013
Comments (1)

There has been a lot of media attention about tonight's supermoon, but what's the real story?

The supermoon is really called a perigee moon. It's when the full moon occurs at perigee and the Moon is closest to us, on its orbit around the Earth.

perigee moon When the full moon occurs at perigee it is about 50,000km closer to us than an apogee moon.
Source: NASA

Ten years ago, NASA wrote one of the first blogs on the perigee moon, with the headline “But will anyone notice?” Two years ago, in 2011, the perigee moon was at its closest in almost 20 years. That's a pretty neat fact and NASA called it the super perigee Moon.

Well, since then it has taken off and now every perigee moon is earning the title of supermoon. 

perigee vs apogee moons A full moon at perigee can be 14% bigger than a full moon at apogee, but it's only easy to see the difference when the moons are side-by-side.
Source: NASA

The statistics sound amazing, over 10% bigger, almost 30% brighter, but that's in comparison to an apogee moon, which occurs when the full moon is furthest away from Earth. In truth, it’s not really enough to notice. Especially when you consider that most full moons across the year occur somewhere between these two extremes.

So by all means, go out and marvel at the magnificent full moon as it rises tonight at sunset and have a think about our place in the Universe – now that's what I call super!


ABC News: "Supermoon appears in Australian skies, bringing king tide"

Comments (1)

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Samuel Princi 24 June, 2013 19:06
Hi Tanya, I am 9 years old. Thank you explaining to me all about the Supermoon. I love going to the planetarium and learning all about the night sky. At school I am making a treasure map how to get from Earth to the moon. from Samuel.
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