Thursday, December 31, 2009
There's a "Blewe" (Blue) Moon Tonight
© Molson Coors
I don't need an astronomer to tell me the moon has been "brighter" the past couple of nights. It's been so bright, I've had trouble sleeping. Yah, I know - I could install window shades. But I like to wake up the "natural" way with sunlight streaming through my windows.
This morning the moon was so bright, it woke me up at 4am. Rather than fight it, I got up, made myself a latte and went to my trusty MacBook Pro to find out what's going on.
I was relieved to find out it wasn't just me. According to a report in the Chicago Tribune, the moon really is brighter.
An astronomer at the Adler Planetarium explained what's up with the moon:
1. There's one day each year when Earth is closest to the sun - which makes the reflection of the sun on the moon brighter. In 2010, it's Jan 2nd.
2. There's one day each month when the moon is closest to Earth, which makes the moon appear to be 7% larger. In 2010, it's Jan 1st.
3. When the moon is full, it rises to a point nearly opposite the sun. Because the sun is low on the horizon during the winter, the full moon rises particularly high.
More reflection + bigger appearance + higher in the sky = brighter moon. Makes sense to me.
But wait, there's more "moon" news today: there's a "blue moon" tonight.
No, the moon doesn't actually turn blue (unless there's a major dust or smoke event - a fire or volcanic eruption). It has to do with an old ecclesiastical calendar (click here for the somewhat complicated explanation).
Here's the simple explanation: a "blue moon" is the second full-moon in a calendar month. It occurs on New Year's Eve every 19 years. Thus the adage referring to a rare event as "once in a blue moon."
The use of the word "blue" in association with this calendar event may have its origins in the Old English word "belewe" or "blewe" which means "to betray." Perhaps a reference to "betraying" the usual perception of one full Moon per calendar month.
So I have something new to celebrate tonight. In addition to New Year's Eve and my wedding anniversary, there's a rare and, some say, auspicious calendar event: a Blue Moon.
Posted by hvhughes at 11:34 AM