Moon reaches closest point to Earth in its elliptical orbit
By Summit Voice
SUMMIT COUNTY — About once a year, the moon, in its elliptical orbit, reaches its closest point to the Earth the same time as the full moon. This year’s so-called supermoon is this weekend, and skywatchers will be treated to a moon that appears 14 percent larger and 30 percent brighter than the average full moon.
At its perigee, the moon is about 30,000 miles closer to Earth then when it’s at its apogee, which explains why the so-called supermoon looks especially bright and large, especially at moonrise, when viewed against a foreground.
This year, the timing is almost perfect, as the moon reaches perigee at 9:30 p.m. on May 5, then becomes completely full just one minute later.
According to NASA, it may be hard to tell that the moon appears bigger than normal.
“There are no rulers floating in the sky to measure lunar diameters. Hanging high overhead with no reference points to provide a sense of scale, one full Moon can seem much like any other,” NASA says on its website.
The best time to get a sense of the supermoon is when the moon is low to the horizon. Psychologists and astronomers don’t completely understand the phenomenon, but the moon always looks bigger when its shining through trees or other foreground objects.
And don’t worry about werewolves or other folklore too much. Though the full moon has a reputation for causing upticks in hospital admissions and crime rates, most modern studies don’t show much of a correlation. The Moon, according to NASA, is less influential than folklore would have us believe.
It is true that the perigeee full moon brings slightly higher “perigean tides,” but according to the National Oceanic and Atmospheric Administration this is nothing to worry about.
In most places, lunar gravity at perigee pulls tide waters only a few centimeters (an inch or so) higher than usual. Local geography can amplify the effect to about 15 centimeters (six inches)–not exactly a great flood.