This one is being aggressively promoted in the media as special because it coincides almost exactly with the solstice. Since the advance of the lunar nodes (the azimuth of where the Moon crosses the ecliptic) is not in resonance with Earth's orbit around the sun, this particular coincidence is no more or less probable, or interesting, than an eclipse falling on any chosen calendar date. All this coincidence really tells us is that we can finally look forward to increasing hours of daylight and solar insolation (although the weather doesn't start warming up until February).
One coincidence that isn't a coincidence is that this eclipse occurs at a full moon. This "insight" comes from an interview with some new-agey sort of person that I heard on the radio. Well, duh! I suppose we can also add the, um, coincidence that we see the eclipse occuring at night. These facts are about as coincidental as a flipped coin that lands head's-up showing an impression of Her Royal Highness. It is also why this eclipse will not be visible from anywhere in Antarctica -- the explanation of which I'll leave as an easily-solved puzzle for the geometrically inclined.
Apart from the obvious things about lunar eclipses, there are a couple of items that are less widely considered. The first is that when we see a lunar eclipse, if someone is on the moon (anywhere on the hemisphere facing Earth) they will be simultaneously viewing a solar eclipse.
...the view from the moon during the eclipse, with the Earth in front of the sun, would be a spectacular red ring in the black sky.It should be no surprise that the colour of the scattered sunlight from the Earth's atmosphere (from its visible circumference) is brownish-red (or copper) since that is the tint the moon takes on during the lunar eclipse. In similar fashion, the frequency of solar eclipses for Moon dwellers is the same as lunar eclipses for Earth dwellers. From the Moon, the apparent diameter of the Earth is quite a bit larger than the Moon appears from Earth and so is more likely to cover the sun.
However, there are no "terran" eclipses when the Earth is full (Moon between the Earth and sun) since the Moon's shadow never covers more than a small area on Earth's surface. That occurs when we on Earth see a solar eclipse.
The second interesting thing about lunar eclipses I want to mention refers back to an earlier post of mine that talked about why the full moon always passes high overhead during the winter months at higher latitudes, like here in Ottawa (also at high southern altitudes such as southern Chile); however that, too, is no coincidence. What this means is that the best lunar eclipses are those that occur around the winter solstice, just like the one this week, because the Moon will pass high overhead for optimal viewing.
Unfortunately this is also what I have always hated about lunar eclipses, because the best ones occur when you have to endure cold winter nights if you want to watch them properly. They're never quite so nice when seen through a window, which in any case will be difficult since in many houses the Moon will be so high as to be blocked by the eaves of the roof. In other words, to stay warm while watching this eclipse you'll probably have to deal with window-glass distortion and an uncomfortable viewing angle.
Despite having said all this, my plan (I am actually writing this the night before) is to stay warm and in bed and pass on the joy and the cold. Anticipation for this event by people here in Ottawa may be for naught in any case since it now looks as if clouds are going to spoil the event. Well, there's always the internet so I'm sure there will be lots of photos making the rounds on astronomy blogs Tuesday morning.
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