http://www3.lastampa.it/scienza/sezioni/news/articolo/lstp/394060/
The night of the giant moon
Moonlight tonight
appears larger than usual, and brighter than usual Nigh for a whole hour, "unfounded fears of catastrophic"
Piero Bianucci
turin
This evening the moon will be full at 19.10 and an hour later, at 20.08, you will find at 356,575 km from us, that is a distance quite close to minimum possible. In addition, during the night the full moon rise high in the sky. The three connections will increase by an amount almost imperceptible its brightness and apparent diameter. This is the news. The rest - maybe you read other newspapers or hear on TV - is legend. It really is not true that the approach to the Earth and brightness of tonight they have something special. E 'wrong to think that this favors the telescopic observation of the lunar surface. And it is terrorism to suggest the idea, as certain websites, the approach involves some risk (eg earthquakes). Let us start from a distance. The Moon's orbit around the Earth is elliptical. So every lunation, ie, every 29 days, the Moon passes at its closest to us (perigee) and the farthest (apogee). Distance minimum and maximum, however, are not constant. The attraction of the sun and other factors sprawled lunar orbit. That is the perigee oscillates around 363,300 km. The closest perigee, that is the shortest distance possible, is 356,371 km, less than two hundred of the alleged record of this evening. Which is not a record. In the millennium that goes from 1548 to 2479 for 14 times the Moon passes less than 356,425 km, and a hundred times the distance tonight. Are data obtained with the best theory to calculate the distance of the moon available today, the Bureau des Longitudes ELP2000/82 of Paris, which takes into account factors 9618 journals, some of which are relevant to just 2 cm. Such precision today can be verified. It is made with a laser beam shot into the mirrors left on the moon by astronauts forty years ago. From the time of return of the light beam is obtained away with the uncertainty of a few centimeters. Diameter. It 's true that when the Moon is closest to its diameter is larger, as is the case for any object. But to our eyes is not so. Regardless of the distance, the Moon appears larger when it is low on the horizon. That depends on an optical illusion already studied by the pupil of Benedetto Castelli and Galileo's father is then clarified by psychologist Mario Ponzo in around 1930. Moon, sun, constellations, seem more large when touching the horizon because our brain tends to overestimate the size by comparison with the landscape and terrestrial objects. Brightness. A small distance makes the moon a little 'brighter because it increases the apparent surface that reflects sunlight, but they count much more height on the horizon and transparency of the air. Telescopic observation. The full moon is the least likely to amateurs at this stage because the sunlight does not create shadows. Then, mountains, craters and valleys flatten out, becoming almost invisible. Finally, the risk of earthquakes. The attraction of the moon (tide) varies little between a narrow and a wide perigee. In However, this is not particularly close. Please note: compared to this morning the Moon will be closer to 200 km in the following upcoming dates: December 6, 2052, 29 January 2116, February 9, 2134, December 22, 2238. The true record of the millennium there will be 1 January 2257 with a distance of 356,371 from center to center of the two celestial bodies. Greetings.
Paoletta
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