MOUNT VERNON — Beginning at 8:43 p.m. most residents of North America can witness the beginning of a total lunar eclipse, cloud cover permitting. In Knox County, Weather.com predicts mostly cloudy skies at 8 p.m. then clearing through midnight.
Although there were two total lunar eclipses last year, neither were completely visible to the entire continental United States.
An eclipse occurs when the moon passes through the Earth’s umbral shadow. Tonight’s eclipse is predicted to last until 12:09 a.m. Astronomers predict the moon will become completely enshrouded at 10:01 p.m. and will remain in the “totality” of the Earth’s shadow for 51 minutes.
According to NASA, the last total lunar eclipse visible from the entire United States occurred on Nov. 9, 2003.
At its darkest point, the moon will appear red. This is because sunlight reaching the moon passes through Earth’s atmosphere, scattering the light. Since only longer wavelengths are able to pass through the dusty atmosphere, the light eventually reflecting off the moon appears red to us. This is the same effect that causes sunrises and sunsets to appear red on the horizon.
Paula Turner, an associate professor of physics at Kenyon College, said that “one of the things that can be interesting [during an eclipse] is you can actually see the effect of light pollution.”
“In it’s totality, the only source of light on the moon is light scattered by the sunsets around the edge of the Earth or light actually produced from the Earth (i.e. cities). We can measure this effect,” said Turner.
Turner, who is also director of the Miller Observatory on Kenyon’s campus, said that if the skies clear enough, Kenyon would open the observatory to public, free of charge, from 9 to 11:30 p.m.. “It really depends on the weather,” said Turner.
There are anywhere from zero to three lunar eclipses (partial or total) each year, according to NASA. The last time three total eclipses occurred in one year was in 1982. During the five millennium period from 3,000 B.C. to 2,000 B.C. there are 7,718 partial or total lunar eclipses, according to NASA.
