The Ellensburg WA sky for the week of 2/11/17

Saturday: “Oooo, they’re little runaways. Orion’s stars moved fast. Tried to make a getaway. Ooo-oo, they’re little runaways,” sang Bon Jovi in his astronomical hit “Runaway.  At least that’s what I hear when I listen to the song. After all, it fits the recently calculated trajectory of AE Aurigae, Mu Columbae, and 53 Arietis. Extrapolating the actual motion of these three stars back in time, they were all in the location of the star-forming region called the Orion Nebula a few million years ago. What kicked these stars out? Not paying rent? Excessive partying? No, it was simply gravitation interactions with near-by stars. Find out more about the eviction at http://goo.gl/UeLwKQ. Orion is about four fists held upright and at arm’s length above due south at 8 p.m.

Sunday: Venus is about two fists above the west-southwest horizon at 7 p.m. Mars is less than a fist to the upper left of Venus.

Monday: Winter is a good time to see the thick band of the Milky Way galaxy. It arches high in the high in the early evening starting in the southeast by Sirius, the brightest star in the night sky. Climbing from Sirius through the "horns" of Taurus high overhead, it drops down toward M-shaped Cassiopeia in the north and the tail of Cygnus, the swan, in the northwest.

Tuesday: According to Greek mythology, the beautiful princess Andromeda was chained to a rock next to the ocean. Cetus the sea monster was about to devour her in order to punish her family. It seemed that all was lost. But, along came the great warrior Perseus, fresh off his defeat of the evil Gorgon, Medusa. The only similarity between Andromeda and Medusa was that Andromeda caused people to stand still and stare at her beauty while Medusa turned people to stone because of her ugliness. (And, you thought you looked bad in the morning.) Even though Perseus’ standing as the son of King Zeus and the slayer of Medusa was probably enough to win Andromeda under normal circumstances, Andromeda’s impending death-by-sea-monster was not a normal circumstance. So, Perseus drove his sword into the sea monsters neck and killed it. In a little known addendum to the story, Perseus carved “Percy (heart symbol) Andi” in the rock, thus originating the use of the heart symbol as a substitute for the word “love”.

You can find these lovers in the sky this Valentine’s Day. Just remember it is rude to stare – and you never know when you might turn to stone. First, find the Great Square of Pegasus at 7 p.m. between one and a half and three and a half fists above the west horizon. The lowest star in Andromeda is the top star in the square. This represents Andromeda’s head. Perseus is at her feet, nearly straight overhead. Mirphak, the brightest star in Perseus, is about eight fists above the west horizon. Perseus’ body is represented by the line of stars to the left and right of Mirphak.

Wednesday: Jupiter is less than one fist above the east-southeast horizon at 11 p.m. The gibbious Moon has just crept up from the horizon to spy on it.

Thursday: You think wintertime weather is bad in Ellensburg. Astronomers have discovered storms and earth-sized clouds on a brown dwarf. These are cool, small stars that are not massive enough to fuse hydrogen atoms and fuse hydrogen. In fact, they are more similar to gas giant planets such as Jupiter that to the Sun. In this context, the discovery of storms similar to the giant Red Spot on Jupiter makes sense. For more information, go to http://goo.gl/jQS3k.

Friday: This President’s Day weekend, let’s remember Abraham Lincoln: 16^th president, country lawyer, man on the penny, vampire hunter, and astronomer. Vampire hunter? No. Astronomer? Well, maybe not an astronomer, but someone who used observational evidence from the sky to solve a problem. In 1858, Lincoln defended Duff Armstrong, a family friend who was accused of murder. The prosecution thought they had a strong case because their primary witnesses claimed to have observed the killing by the light of the nearly full moon. Let’s listen in on the trial courtesy of the 1939 film, Young Mr. Lincoln.

Lincoln: How’d you see so well?

Witness: I told you it was Moon bright, Mr. Lincoln.

Lincoln: Moon bright.

Witness: Yes.

(Dramatic pause as Lincoln reaches for something)

Lincoln: Look at this. Go on, look at it. It’s the Farmer’s Almanack (sic). You see what it says about the Moon. That the Moon… set at 10: 21, 40 minutes before the killing took place. So you see it couldn’t have been Moon bright, could it?

Lincoln used the known information about Moon rising and setting times for August 29, 1858 as evidence in a trial. This is one of the earliest uses of forensic astronomy. You may confirm Lincoln’s findings on the Moon set time by going to http://goo.gl/PsCmff, the US Naval Observatory website, and filling out Form A. For more information about Lincoln’s “almanac trial”, go to http://goo.gl/r83q4X.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.