What is a supermoon, why does it happen and how can you see it?

The spectacular phenomena will not occur again until next year, but why might the moon appear larger in the sky for some this evening?

It’s supermoon time, but what is it and why does it happen?

A supermoon, is just that, a little bit super. It may not look like those photos you see where it looks like a big dinner plate behind a high rise in the foreground which looks like a lollipop stick – most of these are edited.

Despite that, it’s still a nice thing to see, where the moon appears bigger and brighter than normal.

The moon orbits the earth every 27 days and the orbit is not a perfect circle, it’s an ellipse which means the distance between the earth and moon is constantly changing.

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At the end of June, just two weeks ago the moon has reached what’s known as the apogee, which is the furthest point away from the earth, but today is at its closet point, or perigee.

Since June 29 the moon has moved 30,000 miles closer to earth and while that sounds a lot, but in space terms, is very small.

But saying that, the moon does appear a little bigger in the sky, especially when the full moon coincides with the perigee.

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Tonight’s full moon will appear 14% bigger and 30% brighter than usual and the moon rise tonight will be between 10.30pm in the south and 11pm in the north of the country. Also, we should have broken cloud this evening, so much of the country should be able to catch a glimpse of it.

After the first half hour the moon will start to look smaller as it rises into the night sky. Often we see the moon as a very big disc as it rises, but then it seems much smaller when it’s right above us, but of course it is not changing size, it’s down to something quite amazing, called the moon illusion.

Our brains are tricked into thinking the moon is bigger on the horizon as we see it compared to trees, hills and buildings in the foreground, but as it rises and gets further away from these it appears smaller. So the next time you see a ‘huge’ moon rising, which isn’t a supermoon, your brain is playing tricks on you.

Enjoy tonight’s supermoon, and if you don’t catch it, the next one will be on August 1 next year.