Saturday, January 2, 2016

Tonight's Sky for January 2: The Earliest Sunsets, Third Quarter Moon

While the shortest day of the year, the Winter Solstice, is about two weeks in the past, the earliest sunsets of the year will occur this week for us here on Earth, regardless of where you live, despite the fact that sunset times vary depending on latitude.
Right now, the Sun is setting at its earliest time and will continue to set at the same time for the next few days before gradually creeping later into the evening.
So, with the Sun down so early (and resulting in the longest nights of the year), why not head out and view the stars? After all, the December sky has a lot to offer. After all, at what point of the year can you see a year's worth of stars in a given night? Don't believe me? Head out just after dark tonight and look up for the Summer Triangle. Then, just before sunrise, go out again and look for a bright blue star in the Northeast just above the horizon. That's Vega, the same Summer Triangle Star you saw the previous night.

Additionally, today, the Moon, second brightest object in the sky, has reached the Third Quarter phase, which means that it is exactly 270 degrees around its orbit of Earth.

As for lunar mechanics, the Moon is always half lit. The reason we don't always see it as such is thanks to orientation in relation to us. Right now, with the Moon at a 90 degree angle relative to the Earth and Sun, we see the Moon as half lit and half dark, leading to the popular, erroneous phrase 'half Moon.'

After today, we will see less and less of the Moon as its lit side turns more away from us and heads toward a new lunar cycle.   

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