Western Slope Skies 12/6/13

Look low in southwest as the sky darkens in early December. That brilliant “evening star” is actually not a star, but the planet Venus. 

Venus is at its brightest now, in part because it’s relatively close by, only about 35 million miles from Earth. Venus is so very bright that it can cast shadows, and it’s sometimes confused with airplane landing lights, or even reported as a UFO. 

By late December, Venus will become harder to see, because it will soon move between Earth and the Sun, appearing to pass just north of our Sun on January 11. But, by late January, Venus will re-appear as a brilliant “morning star,” low in the southeast, just before dawn.             

If you have a small telescope or binoculars, point them at Venus. You will see that Venus appears as a crescent this month. Like other planets, Venus shines only by reflected sunlight. When we see Venus as a crescent, we are seeing just a small part of its sun-lit side, and a larger part of its dark or night side. 

As December progresses, Venus’ crescent becomes thinner, as Venus starts to move between the Earth and the Sun.      

Venus is sometimes called Earth’s sister planet, because it is only slightly smaller than Earth and has a similar density and, like Earth, a geologically young surface. 

But, despite its beautiful appearance, surface conditions on Venus are nasty. The temperature is 860 degrees F and the crushing atmospheric pressure is like being submerged to a depth of 3000 ft in Earth’s ocean.