Wednesday, January 11, 2012

The Ellensburg Sky for the week of 1/14/12

Saturday: Who can forget that memorable song by Three Dog Constellations Night, “The sky is black. The stars are white. Together we learn to find the light.” Well, maybe it didn’t go like that. This is good because not all stars are white. Most stars are too dim to notice a color. But, the stars in the constellation Orion provide a noticeable contrast. Betelgeuse, five fists held upright and at arm’s length above due south at 10:30 p.m. is a red giant. Rigel, the bright star about two fists to the lower right of Betelgeuse, is a blue giant.
By the way, the three dog constellations are Canis Major, the greater dog; Canis Minor, the lesser dog; and Canes Venatici, the hunting dogs. Canis Major contains Sirius, the brightest star in the nighttime sky.

Sunday: The Weather Girls recorded “It’s Raining Men” in 1982. This weekend, The Phobos-Grunt Boys will be singing, “It’s raining probes, hallelujah. It’s raining probes. Should have gone to Mars. Launched. Burn, didn’t work. Russia’s good at clean and jerk.” Russia launched the unmanned Phobos-Grunt probe on November 9. It was supposed to make the 1.25 year trip to Mars’ moon Phobos, study the surroundings, collect soil samples, and bring them back to Earth. However, the final boost to push it from Earth’s gravitational pull failed and it got stuck in low earth orbit. It is expected to burn up in the atmosphere this weekend with any large pieces reaching Earth on Sunday.

Monday: This morning’s last quarter Moon is in the constellation Virgo, making a small triangle with the bright Spica to its upper right and Saturn to its upper left. The triangle is about three fists above the south horizon at 6:30 a.m.

Tuesday: How do you study the life cycle of a dog? Easy. Get a dog from the animal shelter, care for it for 15 years and study it. How do you study the life cycle of a star? Easy. Pick a star, watch it for a few billion years, and…. Wait a minute. Astronomers can’t observe something for a few billion years. Instead, they study stars that are at different points in their long life cycle and piece together the information from those different stars. What they do is like studying a one-year-old dog for a few minutes, then studying a different two-year-old dog for a few minutes, and so on. The sky in and near the constellation Orion provides an example of four objects at different points of star life.
First, find Rigel, the bright star in the lower right corner of the constellation Orion. This star, rapidly burning its fuel for a high energy but short lived existence, is three and a half fists above due south at 9:30 p.m. About one fist up and to the left are the three objects of Orion’s sword holder. The middle “star” is really a star forming region called the Orion nebula. There you’ll find baby Suns. Now, look about two fists to the right and a little below Rigel. You should be looking at a star that is about one tenth as bright as Rigel but still the brightest in its local region. The third star to the right of that star is Epsilon Eridani, the most Sun-like close and bright star. Betelgeuse, in the upper left corner of Orion, is a star at the end of its life that started out life a bit larger than the Sun.

Wednesday: Jupiter is five fists above the southwest horizon at 8 p.m.

Thursday: January is the coldest month of the year so it is time to turn up the furnace. Fornax the furnace one fist above due south at 7 p.m.

Friday: Venus is two fists above the southwest horizon at 6 p.m.

The positional information in this column about stars and planets is typically accurate for the entire week.

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