I don’t know about you, but I’m already feeling the pressure of December madness. Really it’s a fantastic time of the year when we catch up with friends, celebrate with colleagues and generally wind things up for the summer. But cramming all this in alongside final deadlines and the Christmas shopping can be a mighty task!
When it all gets a bit too frantic and crazy, there’s nothing like sitting back and taking in the night sky. And this month, there’s even more reason to do so.
This beautiful composition shows the extent of the Earth's shadow. It was taken from Europe, so you might notice that the Moon appears upside down.
Source: Laurent Laveder
During the early hours of Sunday 11th December there will be a Total Lunar Eclipse. We can watch the Moon change colour as it plunges into the Earth’s shadow.
The eclipse begins at 11:46pm (AEDT) on Saturday 10th December as the Sun, Earth and Moon fall into line. At first, the shadow will appear to take a bite out of the Moon. Then, the Moon will enter full shadow or totality, just after 1am on Sunday morning. It will stay in shadow for 51 minutes, a little on the short side for a lunar eclipse as they often continue for over an hour.
By 2am, the Moon will begin to light up again and it’s amazing how bright that first glimpse can be. At 3.17am all will be back to normal.
The interesting thing about an eclipse is that the shadow isn’t completely dark. The Moon takes on a reddish glow as light travels through the Earth’s atmosphere. Depending on conditions, it can also take on a hint of blue around the edges from light that passes through the ozone layer in the Earth’s upper atmosphere.
So what might we see during this eclipse? On NASA’s Science news website, atmospheric scientist Richard Keen of the University of Colarado says:
"I expect this eclipse to be bright orange, or even copper-coloured, with a possible hint of turquoise at the edge."
Sounds lovely, doesn't it? Apparently our atmosphere is nice and clear at the moment. Let's just hope the clouds stay away.
Best to try for this eclipse as we are coming up to some lean years. The next lunar eclipse will be a partial in June 2012. But to see a Total Lunar Eclipse, we'll have to wait until April 2014.
The Moon plunges into the Earth's shadow.
Source: Public Domain
Eclipses are uncommon because the Moon's orbit (shown in green) is misaligned with the Earth's orbit around the Sun (shown in blue). If the Moon and Earth orbited in the same plane, we'd see an eclipse every Full Moon (as well as a solar eclipse every New Moon). But because the Moon's orbit is tilted by just 5 degrees, most of the time the Moon misses the Earth's shadow and moves either above or below it.
So enjoy taking some time out to appreciate the Universe we live in, as long as the weather lets us!