Stuff I did not know

Carrying on with the theme of 'this is bigger', tonight's full moon is to be the largest of the year - 30% brighter and 14% larger from one edge to the other. It's immaterial to me here in Scotland because tonight we have our usual complete cloud cover. If it's clear where you are, though, you might want to go outside and have a look around. From the NASA website:

Dec. 9, 2008: No, you can not see Neil Armstrong's footprint. But go ahead and look: The full Moon of Dec. 12th is the biggest and brightest full Moon of the year.

It's no illusion. Some full Moons are genuinely larger than others and this Friday's is a whopper. Why? The Moon's orbit is an ellipse with one side 50,000 km closer to Earth than the other: diagram. In the language of astronomy, the two extremes are called "apogee" (far away) and "perigee" (nearby). On Dec. 12th, the Moon becomes full a scant 4 hours after reaching perigee, making it 14% bigger and 30% brighter than lesser full Moons we've seen earlier in 2008.