Wednesday, April 15, 2015
The Ellensburg WA sky for the week of 4/18/15
Saturday: Venus is two and a half fists held upright and at arm’s length above the west horizon at 9 p.m.
Sunday: Tonight at 8 p.m., listen to an Eminem song. Next, eat some M & M candies. Finally, look one fist above the west horizon to see the Moon and Mars and Mercury side by side. Mars is less than a half a fist to the right of the Moon and Mercury is a half fist to the lower right of Mars. That’s right. Watch the sky’s own M and M and M while eating M & Ms while listening to Eminem. You’ll have a great time or my name’s not (what?). My name’s not (who?). My name’s not… Slim Shady.
Monday: Sirius, the brightest star in the night sky, is dipping lower and lower. (Do you like how I used the word “dipping”? Big Dipper. Get it? Never mind.) It is only a half a fist above the west-southwest horizon at 10 p.m.
Tuesday: Its two small moons, Phobos and Deimos, are not visible in typical backyard telescopes. But they are an interesting study. The prevailing view among most astronomers is that they are captured asteroids. That makes sense given Mars’ proximity to the asteroid belt. But resent findings by European astronomers indicate that Phobos is very porous and made of material similar to the surface of Mars. This implies that Phobos may consist of chunks of Martian debris that was blasted off by numerous impacts and gravitationally bound together. Unfortunately, the Russian Phobos-Grunt probe launched late 2011 to collect material from Phobos crashed to Earth after malfunctioning. For more information about this new model of Phobos’ formation, go to http://goo.gl/8sw3rM.
Wednesday: Remember the old saying: April showers bring… meteors. The Lyrid meteor shower peaks this morning and tomorrow morning. The meteors appear to come from a point to the right of the bright bluish star Vega in the constellation Lyra the lyre. This point is about three fists above the east-northeast horizon at midnight tonight and close to straight overhead near dawn. The best time to look is just before dawn since that is when the radiant, or point from which the meteors appear to come, is high in the sky. This year, the Moon is in the waxing crescent phase meaning it has set long before the prime viewing time. Typically, this is one of the least interesting major meteor showers of the year. However, it is also one of the most unpredictable. As recently as 1982, there were 90 meteors visible during a single hour. In addition, the Lyrid meteor shower has historical interest because it was one of the first ones observed. Chinese records say “stars fell like rain” in the shower of 687 B.C. As your Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. Meteors are tiny rocks that hit the Earth and burn up in the atmosphere. For more information, go to http://goo.gl/j87bVB.
Thursday: As the weather warms up, people start thinking about swimming in a nice cool body of water. Recently, astronomers have discovered evidence an ocean about 20 miles beneath the surface of Saturn’s moon Enceledas. NASA’s Cassini probe measured variations in how the moon’s gravity pulled on the orbiting spacecraft. These variations can be explained by a large amount of liquid water under one section of the ice because liquid water is denser than an equal volume of ice. While you need a very large telescope to see Enceledas, Saturn is one fist above due southeast at midnight.
Friday: Capella is a half a fist above the north-northeast horizon at 5 a.m.
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 http://nightsky.jpl.nasa.gov/planner.cfm.