Wednesday, February 1, 2017

Planetary Perspective


This month has been somewhat unusual for our area so far this year. The snow that started early in December has hung around until just a couple of days ago; there are still a few traces left. Yesterday and today have finally produced clear days. Last night a "cool" assembly of two planets and the Moon was visible in the evening sky (figuratively, and literally - temperature was near zero C at our place), and I took this picture:

Moon, Mars (above the Moon), and Venus - click on the picture to see a larger image.

You'll notice the "earthshine" outlining the part of the Moon which is not illuminated by the Sun. If you were on the Moon on the side which faces the Earth, the sun-lit Earth would have been a couple of days past "full Earth" in the Moon's sky, and would have been very bright. So we see that part of the Moon lit up by the sunlight which shines onto Earth, is partially reflected to the Moon, lights up the darker part of the Moon, and that reflected light is partially re-reflected back to Earth.

Earth passed Mars some months ago, so Mars is trailing, and will soon be on the other side of the Sun from the Earth's point of view, and Venus is moving faster than Earth towards its upcoming pass between the Earth and the Sun.

It's all a matter of perspective...

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