Thursday 8 December 2016

What is a 'supermoon' and when can I see the largest moon in 70 years?

Published 13/11/2016 | 19:39

A man takes picture of the screen displaying the moon, appearing in a dim red colour, which is covered by the Earth's shadow during a total lunar eclipse in Warsaw
A man takes picture of the screen displaying the moon, appearing in a dim red colour, which is covered by the Earth's shadow during a total lunar eclipse in Warsaw

Ever looked up at the night sky to see a full moon so close you could almost touch it? Well done, you've spotted a supermoon.

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The impressive sight happens when a full moon is closest to Earth. It orbits our planet in an oval shape so sometimes it comes closer to us than at other times. To us Earth-lings, the moon appears 30 per cent brighter and 14 per cent bigger.

By the way, supermoon is not an astrological term. It's scientific name is perigee-syzygy, but supermoon is more catchy, and is used by the media to describe our celestial neighbour when it gets up close.

Astrologer Richard Nolle first came up with the term and he defined it as "… a new or full moon which occurs with the moon at or near (within 90 per cent of) its closest approach to Earth in a given orbit", according to earthsky.org.

When is the next supermoon?

Monday, November 14. This supermoon will be the biggest and brightest in 70 years, so it will definitely be worth a look.

The supermoon raises behind seagulls on the beach in Evanston, Illinois
The supermoon raises behind seagulls on the beach in Evanston, Illinois

The "undeniably beautiful" astronomical event will not come again until November 25, 2034, space agency Nasa said.

How can I see it?

The moon will become full at 13:52 GMT on Monday, so the best time to view it in Ireland will be when the sun is setting in the late afternoon. The closer to the horizon it is, the bigger it will appear.

Pick a place with the least light pollution. Paul Thomsett, chairman of the South East Kent Astronomical Society said: "As long as the skies are clear and you have a good view to the south you will have no trouble seeing our nearest celestial neighbour blazing in the night sky."

The 'Supermoon' in Dublin
The 'Supermoon' in Dublin

"Weather permitting [it] will be visible without the need for a telescope."

If you miss it, don't worry. The moon will only be a fraction smaller on November 15.

What do I look for?

Robin Scagell, vice-president of the Society for Popular Astronomy, said: "It will be above rooftops and trees and chimneys and always appears bigger that way because you're comparing it to foreground objects.

"I'm always pleased for people to get their binoculars out and look up at the craters and the seas."

As well as being closer and brighter, the moon will look orange and red when it first rises. As the moon gets higher in the sky, it returns to its normal white/yellow colour.

The 'supermoon' will be brighter and appear larger than normal
The 'supermoon' will be brighter and appear larger than normal

How common are supermoons?

They're fairly frequent, although November's supermoon will be a once-in-a-generation sight. There are six supermoons in 2016. We've already had four, and after next week there's one on December 14. 

Each full moon of the year is given a name - although they vary according to the source. October's full moon is referred to as the Hunter's moon because it appears very soon after sunset, and traditionally generated more light for farmers working in the fields and hunters to spot wildlife.

How close does the moon actually get?

It might look close, but of course it's not that close. November 14's full moon will be the closest for 70 years. The moon will come 221,524 miles from Earth - almost touching distance in space terms.

The closest full moon of the whole of the 21st century will fall on December 6, 2052.

Will the tides be larger?

Possibly, yes. Most people know that tides are governed by the gravitational pull of the moon and, to a lesser extent, the sun. Because the sun and moon go through different alignments, this affects the size of the tides.

When the moon is closer to Earth, it can lead to slightly higher tides, and greater variations between the tides.

Tell me more about the moon

The moon is the Earth's only natural satellite. It's 4.6 billion years old and was formed between 30-50 million years after the solar system was formed.

The moon is smaller than Earth. It's about the same size as Pluto. In fact its surface area is actually less than the surface area of Asia - about 14.6 million square miles, according to space.com.

A new moon occurs every 29.5 days. The moon 'disappears' from the sky when it is between Earth and the sun with it’s illuminated side facing away from us.

When the moon is opposite the sun we see a full moon as it's fully lit up by the sun. In between, we see a crescent moon as only some reflected sunlight is seen.

The moon has earthquakes, caused by the gravitational pull of Earth. Experts believe the moon has a molten core, just like Earth.

Telegraph.co.uk

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