BIGGEST FULL MOON OF THE YEAR: If you think tonight's Moon looks unusually big, you're right. It's the biggest full Moon of 2010. Astronomers call it a "perigee Moon," some 14% wider and 30% brighter than lesser full Moons of the year.
Image credit and copyright: Anthony Ayiomamitis: details.
Johannes Kepler explained the phenomenon 400 years ago. The Moon's orbit around Earth is not a circle but an ellipse, with one side 50,000 km closer to Earth than the other. Astronomers call the point of closest approach "perigee," and that is where the Moon will be Friday night through Saturday morning: diagram.
A good time to look is around sunset when the Moon is near the eastern horizon. At that time, illusion mixes with reality to produce a truly stunning view. For reasons not fully understood by psychologists, low-hanging Moons look unnaturally large when they beam through foreground objects such as buildings and trees. Why not let the "Moon illusion" amplify a full Moon that's extra-big to begin with? The swollen orb rising in the east may seem close enough to touch.
And what's that bright orange star right beside the Moon? Read on...
IT'S MARS! In a coincidence of celestial proportions, the Moon and Mars are having close encounters with Earth at the same time. Moreover, the two will spend Friday night gliding across the sky side-by-side. It's a must-see event: sky map.
Full text: http://spaceweather.com/ (It's a bookmark-worth site overall, too.)
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