Wednesday, August 30, 2017
Saturday: The Ellensburg Rodeo is a “Top-25” rodeo. What does it take to be a “Top-25” star? There are many ways to rank stars. The most obvious way for a casual observer to rank stars is by apparent brightness. The apparent brightness is the brightness of a star as seen from Earth, regardless of its distance from the Earth. Shaula (pronounced Show’-la) is the 25th brightest star in the nighttime sky as seen from Earth. It represents the stinger of Scorpius the scorpion. In fact, Shaula means stinger in Arabic. Shaula has a visual brightness rating of 1.62. Sirius, the brightest star has a visual brightness rating of -1.46. (Smaller numbers mean brighter objects.) The dimmest objects that can be seen with the naked eye have a visual brightness rating of about 6. There are approximately 6,000 stars with a lower numbered visual brightness rating than 6 meaning there are 6,000 stars visible to the naked eye. Shaula is a blue sub-giant star that radiates 35,000 times more energy than the Sun. It is 700 light years away making it one of the most distant bright stars. Shaula is a challenge to find because it never gets more than a half a fist above the horizon. Look for it tonight about a half a fist held upright and at arm’s length above the south horizon, a little bit west of due south, at 8:30.
Sunday: School starts this week so it is time for a little geometry review. A square is a regular quadrilateral, which means it has four equal sides, four equal angles, and it uses the restroom on a set schedule. Go outside at 10 p.m. tonight with notebook in hand to sketch one. The Great Square of Pegasus is balancing on its corner two and a half fists above due east. The top corner of the square is two fists above the bottom corner. The other two corners are to the left and right of the line segment connecting the top and bottom corners.
Monday: Labor Day was the brainchild of labor unions and is dedicated to American workers. The first Labor Day was celebrated in 1882. The Greek mythical hero Hercules probably wished there was a Labor Day to commemorate his work. As punishment for killing his family while he was temporarily insane, he had to perform twelve nearly impossible tasks such as killing monsters or stealing things from deities. Hmmm. Maybe we shouldn’t commemorate his labors. But we can enjoy his constellation. The keystone asterism representing the body of Hercules is six fists above the west horizon at 10 p.m. For more information about the Labors of Hercules, go to http://goo.gl/ozVF5.
Tuesday: Geometry review, part 2. Go outside at 10 p.m. tonight with notebook in hand. (Good teaching involves a little repetition.) You’ll have an easy time seeing your notebook because the moon is just a little past full. A triangle is a polygon with three corners and three line segments as sides. A good example is the Summer Triangle made up of the bright stars Vega, Deneb and Altair. Vega, the brightest star in the triangle, is a little bit southwest of straight overhead. Deneb is a little bit east of straight overhead and Altair is five fists above the south horizon.
Wednesday: Jupiter is less than one fist above the west-southwest horizon at 8 p.m. Saturn is two fists above the south horizon.
Thursday: Venus is two fists above due east at 6 a.m. But the more interesting sight is to the lower left of Venus, halfway to the horizon. Mercury, Regulus, and Mars make a little line less than a half a fist long. Mercury is the brightest objects and is in the upper right. Mars is the dimmest in the lower left.
Friday: “I’m a little teapot, short and stout. The galactic center, I pour it out.” (I’m a Little Teapot, astronomy version, 2014.) Despite its great size and importance, the center of our Milky Way galaxy and its giant black hole remains hidden to the naked eye behind thick clouds of gas and dust. By plotting the orbits of stars near the middle of the galaxy, astronomers have determined that the black hole’s mass is equal to about 4.5 million Suns. While you can’t see the actual galactic center, you can gaze in the direction of the center by looking just to the right of the teapot asterism in the constellation Sagittarius. This point is about one fist above the south-southwest horizon at 9 p.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.
Thursday, August 24, 2017
Saturday: Arcturus is four fists above the west-southwest horizon at 10:30 p.m. This star, whose name means bear watcher, is the brightest in the sky’s northern hemisphere. It follows Ursa Major, the Great Bear, around the North Star. Arcturus is the closest giant star to Earth. It is one of the few stars whose diameter can be measured directly rather than being inferred from its density and mass, which, themselves are derived from other parameters.
Sunday: Have you ever gone to a family reunion, looked around and asked, “How in the world are we related to each other?” Astronomers look around the Solar System and wonder if there is life anywhere else that we are related to. The Mars Science Laboratory landed on Mars in 2012 to investigate whether it ever had conditions favorable for life. The Venus Express studied the atmosphere of Venus from 2006 to 2014. The Cassini Mission continues to study the plume of complex organic chemicals streaming from Saturn’s moon Enceladus. NASA and the European Space Agency are planning missions to study Europa, the Jovian moon with an ice-covered ocean. And many astronomers consider the methane haze in the atmosphere in Saturn’s moon Titan similar to that of the early Earth. To learn more about the search for life in the Solar System and beyond, go to https://astrobiology.nasa.gov/. While you won’t see anyone waving back, you can see Mars and Venus in the early morning sky. At 5:45 a.m., Mars is a half a fist above the east-northeast horizon and Venus is two fists above the east horizon.
Monday: What did you do last Monday? Hopefully, many of you watched the solar eclipse safely. Many professional and citizen scientists, including some from Central Washington University, acquired valuable eclipse data. Read about a summary of three projects here: http://www.skyandtelescope.com/2017-total-solar-eclipse/eclipse-seen-citizen-scientists/. For more information about CWU’s project, go to https://goo.gl/dNkGNx.
Tuesday: Saturn is a half a fist to the left of the Moon in the southwest sky at 10 p.m.
Wednesday: Deneb is nearly straight overhead at 11:30 p.m. When you look at Deneb, you are seeing light that left Deneb about 1,800 years ago.
Thursday: All stars rotate. Our Sun takes a little less than an Earth month to make one rotation. Astronomers have started to study the relationship between mass, stellar rotation, and planetary formation by aiming NASA’s Kepler space telescope toward the Pleiades open star cluster. All 1,000 stars in this group is nearly the same age, 125 million years old. Since all of the stars are the same age and formed from the same set of materials, astronomers have the ideal “laboratory” to isolate the role star mass plays on star rotation and evolution. Read more about the findings at http://goo.gl/osijIY. See the Pleiades for yourself, one fist above the east-northeast horizon at 11:30 p.m.
Friday: Florence + the Machine sang, “Dog Days are Over”. Today, Florence the large near-Earth asteroid will be singing “Nice to get Close to you, Earth”. The 2.7-mile diameter asteroid will pass within about 18 earth-Moon distances. Even though 2.7 miles in diameter seems small compared to the sixe of astronomical objects we are familiar with such as the Moon, Mars, and the Death Star, it is the largest asteroid to pass this close to Earth since the NASA program to detect near-Earth asteroids began.
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.
Friday, August 11, 2017
Saturday: The Perseid meteor shower hits its peak late tonight/early tomorrow morning. The meteors appear to come from a point just below the W of the constellation Cassiopeia. This point is about two and a half fists held upright and at arm’s length above the northeast horizon at 11 p.m. By dawn, this point is about seven fists above the northeast horizon. If you fall asleep or forget to set your alarm, you will be able to observe this shower from about 11 p.m. to dawn for the next few nights in about the same location in the sky. The Perseid shower is one of the longest lasting showers. The waning gibbous moon will obscure most of the dimmer meteors. For tips about optimizing your viewing this year, go to http://goo.gl/Ylk9jA. As your Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. These meteors are sand to pea-sized bits of rock that fell off of Comet Swift-Tuttle. They are traveling about 40 miles per second as they collide with the Earth and burn up in the atmosphere.
Sunday: At 9 p.m., Jupiter is one fist above the west-southwest horizon and Saturn is two fists above due south.
Monday: The total solar eclipse is a week from today. If you are lucky enough to find a spot in the path of totality, you know to bring your eclipse glasses. After all, the “total” part of the eclipse lasts two minutes while the partial part lasts two hours. Sky & Telescope magazine has put together a list of things you might not think about needing. Find it at http://www.skyandtelescope.com/2017-total-solar-eclipse/10-things-might-need-eclipse-day/.
Tuesday: Altair, at one corner of the Summer Triangle, is four fists above the southeast horizon at 11 p.m. Altair is one of the closest bright stars, so close that fictional astronauts visited a planet orbiting Altair in the 1956 movie “Forbidden Planet”.
Wednesday: Do you get all of your astronomy news from this column? If so, it is time to up your game. CWU astronomer Cassie Fallscheer is giving a presentation tonight from 6:30 to 7:30 at Hal Holmes Center. Go to https://goo.gl/oEM5vN for more information.
Thursday: Need a caffeine pick-me-up? Make it a double. Need an astronomy pick-me-up? Make it a double double. Find Vega, in the constellation Lyra the lyre, nearly straight overhead at 10:00 tonight. Less than half a fist to the east (or left if you are facing south) of the bright bluish star Vega is the “star” Epsilon Lyra. If you look at Epsilon Lyra through binoculars, it looks like two stars. If you look at Epsilon Lyra through a large enough telescope, you will notice that each star in the pair is itself a pair of stars. Each star in the double is double. Hence, Epsilon Lyra is known as the double double. The stars in each pair orbit a point approximately in the center of each respective pair. The pairs themselves orbit a point between the two pairs.
Friday: Let’s all sing the galactic black hole monster song: “D is for dusty, that’s good enough for me. D is for dusty that’s good enough for me. D is for dusty that’s good enough for me. Oh dusty, dusty, dusty starts with D.” Astronomers know that spiral galaxies such as our own have super massive black holes in the center, black holes that are billions of times the mass of the Sun. They thought they got to be this massive by mergers where two galaxies collide and the gas, dust and black holes at the center of each colliding galaxy form a larger central black hole. But many distant galaxies show no signs of galactic mergers. Astronomers think the black holes at the center of these galaxies grew simply by snacking on the gas and dust that comes from supernova explosions and normal star formation. Just like the Cookie Monster gains weight by snacking on individual cookies rather than eating a cookie factory. Cookie crumbs, I mean dust, block your view of the center of our galaxy. It is about one fist above due south at 10 p.m., between the constellations Sagittarius and Scorpius. For more information, go to http://goo.gl/L9ppJf.
Thursday, August 3, 2017
Saturday: The Perseid meteor shower hits its peak late for the next few nights with Friday and Saturday being the peak of the peak. The meteors appear to come from a point just below the W of the constellation Cassiopeia. This point is about two and a half fists held upright and at arm’s length above the northeast horizon at 11 p.m. By dawn, this point is about seven fists above the northeast horizon. If you fall asleep or forget to set your alarm, you will be able to observe this shower from about 11 p.m. to dawn for the next few nights in about the same location in the sky. The Perseid shower is one of the longest lasting showers. The waning gibbous moon will obscure most of the dimmer meteors. For tips about optimizing your viewing this year, go to http://goo.gl/Ylk9jA. As your Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. These meteors are sand to pea-sized bits of rock that fell off of Comet Swift-Tuttle. They are traveling about 40 miles per second as they collide with the Earth and burn up in the atmosphere.
Sunday: Seventeenth century astronomers documented the appearance of a new star, or “nova”, in 1670. However as modern astronomers studied the records of the star, called Nova Vulpeculae 1670, they realized it didn’t have the characteristics of a typical nova because it didn’t repeatedly brighten and dim. It brightened twice and disappeared for good. Turning their telescopes to the region, they discovered the chemical signature to be characteristic of a very rare collision of two stars. For more information about this discovery, go to http://goo.gl/rJnC2G. Nova Vulpeculae 1670 is right below the binary star system Alberio, the head of Cygnus the swan. Alberio is seven fists above the southeast horizon at 11 p.m.
Monday: Saturn is two fists above due south and Jupiter is one and a half fists above the west-southwest horizon at 9:17 p.m.
Tuesday: If you want to show your loved ones a celestial sign that they should hang up their clothes, show them Brocchi's Cluster, commonly known as the Coat Hanger cluster because of its resemblance to an upside down coat hanger. The cluster is six fists above the southeast horizon at 10:30 p.m., midway between Altair and Vega, the two brightest stars in the Summer Triangle. You'll need binoculars to make out the shape. First find Altair four fists above the southeast horizon. Slowly move your binoculars up toward Vega. You will run into the coat hanger along the way. And while you are at it, put away your shoes.
Wednesday: Venus is two fists above the east horizon at 5 a.m.
Thursday: Many big city dwellers never see the milky white, nearly continuous band of stars known as the Milky Way. As cities grow and add more lights, it has become harder to see the bulk of the Milky Way galaxy, our home in the universe. But, there are two easy ways to see the Milky Way. The first way is to look in the mirror. You are part of the Milky Way. The second way is to look from due north through the point straight overhead (called the zenith) to due south from 10:30 p.m. to 1 a.m. for the next two weeks. This is the time of year when the Milky Way is highest in the sky and away from the city lights on the horizon.
Friday: It’s not too early to start planning for the solar eclipse coming August 21. Sky & Telescope magazine has an article about what to look for if you are in the path of totality: confused animals, the corona, and the diamond rings. Confused? Just read the article at https://goo.gl/BjFGYE. To learn more about the eclipse conditions in your area, go to www.greatamericaneclipse.com.