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The BBC's Sue Nelson
Astronomers disagree about how bright the Moon will be
 real 28k

The BBC's Toby Murcott
Probably the brightest Moon since 1930
 real 28k

Wednesday, 22 December, 1999, 23:23 GMT
Brightest Moon for decades

Moon The Moon will appear 14% bigger and 20% brighter


By BBC News Online Science Editor Dr David Whitehouse

The Moon is a little brighter and bigger in the night sky - but you will be hard-pressed to notice the difference.

The phenomenon is the result of cosmic coincidence.

At 2100 GMT, the Moon was at its nearest point to us in its orbit around Earth (perigee). At the same time, the Moon was about as close as it gets to the Sun. This meant that the sunlight reflected by the Moon was stronger than in the summer.

All this coincides with the fact that Wednesday is the winter solstice, the longest night of the year in the Northern Hemisphere, when the Moon is at its highest point in the sky.

The combined effect meant that the Earth's satellite appeared about 14% bigger and about 20% brighter than normal. But full moons in 1893, 1912, and 1930 were more brilliant, as will be one in 2052.

Cloudy skies

"Although it will be brighter than an ordinary full moon, people looking at it with the naked eye won't be able to notice any difference," said Dr Jacqueline Mitton of the Royal Astronomical Society. "Only practised astronomers will really be able to detect the difference."


Moon The Moon over Rome on Tuesday night
The coincidence of a full moon, a lunar perigee and the solstice all occurring within 24 hours of each other is fairly unusual. The quick succession of all three events on Wednesday is unmatched in the last century and a half.

In the UK, however, rain clouds continue to cover most of the country with the exception of the extreme north west and some of Wales.

The Sun and the Moon are responsible for the Earth's tides and these are expected to be exceptionally high and low over the next few days.

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See also:
22 Jul 99 |  Sci/Tech
The earliest drawing of the Moon?
21 Oct 99 |  Sci/Tech
Moon not quite dead
20 Jul 99 |  Sci/Tech
Apollo Moon experiment still working
09 Jun 99 |  Sci/Tech
Moon's tail spotted

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