Saturday, March 19, 2011

Super Full Moon Tonight

Tonight we will be able to see a rare and beautiful sight in the sky. The full Moon, which rises in the east at sunset, will appear to be 14% larger and perhaps 30% brighter than usual. This is because the Moon’s orbit around the earth is not perfectly round. Sometimes it is closer, and sometimes it is farther away. The orbit’s closest approach to earth is known as its perigee. When this close approach coincides with a full Moon, it is called a “perigee Moon.” Tonight the Moon will orbit closer to the earth than it has in 18 years, which naturally will make it look larger.

The best time to look is when the Moon is near the horizon. For reasons not fully understood by astronomers or psychologists, the low-hanging Moon looks unnaturally large when seen near trees, buildings or other objects in the foreground. The combination of this “Moon illusion” and the “perigee Moon” should produce a truly stunning view.