Moon shadows the sun today
Coeur d'Alene Press | UPDATED 11 years, 1 month AGO
If you're reading this between 2 and 4 p.m., take a look outside, with proper eye protection. If it's not too overcast, you might catch the solar eclipse. We won't have another opportunity in this area until 2017. That one will be a total eclipse.
Today's is just a good partial, but nevertheless a rare treat. From its optimum viewing points it should begin from the right and cover much of the sun's image, a dark circle gliding over what will become a crescent of sunlight.
A solar eclipse happens when the moon passes briefly between Earth and sun, casting the darkest part of its shadow, called the umbra. Total solar eclipses are rare, happening only when a new moon is near a "lunar node" and the Earth, moon, and sun are aligned.
So why doesn't that happen with every new moon? The moon orbits around Earth in an imperfect elliptical path; when it's on one side of the orbit it's closer to Earth than when it's on the other side. The closer side is called the perigee (the farthest, the apogee). The points where the two orbital planes meet are called lunar nodes. Total solar eclipses occur when a new moon takes place near a lunar node and the moon is closest, at its perigee.
Imagining the moon's proximity to Earth varying thus throughout the year, it's easier to see why it seems to change size. The Earth also follows an elliptical orbit around the sun, so the sun similarly seems bigger when it's closer. When sun and moon's perceived sizes thus match closely, an eclipse appears complete.
An eclipse can last a couple of hours, but its greatest coverage last only seconds to minutes. NASA and health experts say never view an eclipse directly; looking straight into the sun is dangerous and sunglasses aren't enough protection. If you have access, welder's glasses are better. Or make your own pinhole projector: Timeanddate.com/eclipse/make-pinhole-projector.html.
Editor's note: Sholeh has eclipsed another year; today is her birthday. If you'd like, send her a happy birthday wish at: [email protected]
Sholeh Patrick is a columnist for the Hagadone News Network. Contact her at [email protected].