Tuesday, August 31, 2010

The Ellensburg sky for the week of 9/4/10

Saturday: Geometry review: part 2. School starts this week so it is time to continue our little geometry review from last week. Did you forget last week’s lesson? Well, go to the litter box, dig out last Saturday’s paper and review it. Then go outside at 9 p.m. with notebook in hand. Ready? A square is a quadrilateral with four sides of equal length and four right angle corners. A good example in the sky is the Great Square, an asterism (group of stars) consisting of three stars from the constellation Pegasus and one star from the constellation Andromeda. At 9 p.m., the bottom of the Great Square is two fists held upright and at arm’s length above due east.

Sunday: There is a lot to see at the Kittitas County Fair. But there is not a lot to see in the sky when you are at the fair because the fair lights, which are fairly bright, obscure most celestial objects. Jupiter is one of the few objects bright enough to be seen. As you are leaving the fair at 10 p.m., look for Jupiter about two fists above the east-southeast horizon. Luckily Galileo didn’t do his observing at the Kittitas County Fair because he would not have been able to see Jupiter’s moons. So what, you say? Galileo’s discovery of the moons of Jupiter provided strong evidence that objects other than the Earth could have satellites providing strong support for a Sun-centered solar system. For more information about Jupiter or observing Jupiter, go to http://astronomy2009.nasa.gov/observe_sep.htm

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. Humm. 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://www.perseus.tufts.edu/Herakles/labors.html.

Tuesday: The calendar says summer is nearing an end. School starting tomorrow says summer is nearing an end. The summer triangle in the sky begs to differ as it is still high in the sky. Vega, the brightest star in the triangle, is a little bit west of straight overhead at sunset. Deneb is a little bit east of straight overhead and Altair is five fists above the south horizon.

Wednesday: Venus is less than a half a fist above the west-southwest horizon at 8 p.m. Mars is a half a fist to the upper right of Venus and the star Spica is a half a fist due right of Venus.

Thursday: Fomalhaut, the brightest star in the constellation Piscis Austrinus, is one fist above the south-southeast horizon at 11 pm. It is the southernmost bright star visible from Ellensburg.

Friday: The bright star Capella is a half a fist above the north-northwest horizon at 9 p.m.

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

Tuesday, August 24, 2010

The Ellensburg sky for the week of 8/28/10

Saturday: School starts next week so it is time for a little geometry review. Go outside at 10 p.m. tonight with notebook in hand. Ready? 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 west of straight overhead. Deneb is a little bit east of straight overhead and Altair is five fists held upright and at arm’s length above the south horizon.

Sunday: Ah, the beauty of classification. A large three-sided figure such as the Summer Triangle is a triangle. Hence the name “Summer Triangle” and not “Summer Sandwich”. Although those little triangle-shaped sandwiches are quite tasty. Where was I? Oh yes, classification. Small three-sided figures are also called triangles. This week, the planets Mars & Venus and the bright star Spica make a tiny triangle low in the western sky right after sunset. At 8:30 tonight, Venus is at the bottom of the triangle, less than half a fist above the west-southwest horizon. Spica is a finger width to the upper left of Venus and Mars is about two finger widths to the upper right of Venus.

Monday: When Galileo looked at Venus nearly 400 years ago, he discovered that Venus goes through phases from new to quarter to full just like our moon does. Thanks to this and Galileo’s many other observations of moons and planets in our Solar System, support for an Earth-centered universe was greatly diminished. To commemorate these findings, NASA has made planets, dwarf planets, and moons this month’s “Hot Topic” for the International Year of Astronomy. For more information, go to http://astronomy2009.nasa.gov/topics_sep.htm.

Tuesday: “I’m a little teapot, short and stout. The galactic center, I pour it out.” (I’m a Little Teapot, astronomy version, 2010.) 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 if 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 see the actual galactic center, you can gaze in the direction of the center by looking 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.

Wednesday: This morning’s last quarter moon is in the constellation Taurus the bull. While the quarter moon phases look smaller than the full moon at a glance, all phases are the same size. Recently, astronomers discovered that the moon has not always been the same size. It contracted about 0.2 km in diameter, out of a total diameter of 3,470 km, as it cooled over three billion years ago.

Thursday: Jupiter is one and a half fists above the east-southeast horizon at 10 p.m.

Friday: 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 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 above the south horizon, a little bit west of due south, at 8:30.

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

Saturday, August 21, 2010

Life on Mars?

I just read an article called “It’s Alive” from the June 2010 issue of Discover Magazine. The author postulates that, according to some scientists, the case for life on Mars has already been settled. In 1976, the probe Viking I gathered samples of Martian dirt and tested for life. In one test, engineer Gilbert Levin put nutrients spiked with radioactive material in the dirt. If there were bacteria in the dirt, they would ingest the nutrients and exhale trace radioactive material. The first trial detected radioactivity. As a check, Levin did a second trial in which the dirt was superheated to kill off any bacteria before adding the radioactive nutrients. This trial did not detect any radioactive respiration. Since this was the only Viking test to support life on Mars, scientists assumed that some nonbiological reaction led to Levin’s results. However, in 1976, the assumption was that organic material is rare in the galaxy. Since then, astronomers have discovered organic material on Saturn’s moon Titan, on comets and meterorites, even in interstellar clouds 26,000 light years from Earth. After years of being overlooked, maybe someday Gilbert Levin will be proven right about life on Mars just like Alfred Wegener was proven right about continental drift after many decades. Lesson to all of us: stick by your conclusions if they are supported by evidence.

Saturday, August 14, 2010

The Ellesnburg sky for the week of 8/21/10

Saturday: Sometimes you find a quarter on the ground. Maybe you find a dollar in the lining of your jacket. But how often do you find a galaxy in a well-known part of the sky? The Hubble Space Telescope discovered a face-on spiral galaxy in the Coma Cluster of galaxies about 320 million light years away. This galaxy, called NGC 4911, contains regions of gas and dust as well as glowing newborn star clusters. The Coma Star cluster is in the constellation Coma Berenices, found two and a half fists held upright and at arm’s length above the west horizon at 9 p.m. For more information about this newly discovered galaxy, plus a zoomable image, go to http://hubblesite.org/newscenter/archive/releases/2010/24/.

Sunday: Venus is a half a fist above the west-southwest horizon at 8:45 p.m. Even though it is so low in the sky, it is highly reflective so you should easily be able to find it by the sunlight bouncing off if it. Use bright Venus to find its dimmer neighbors in the sky. Mars is about a finger’s width to the upper right of Venus. Saturn is about a fist and a half to the right of Venus.

Monday: You may have trouble holding in your water at midnight. But not the Big Dipper. The cup of the Big Dipper is facing upward in a water-holding orientation about two fists above the north horizon at midnight.

Tuesday: When the Moon is full, it is difficult to see dim objects in the sky because of the sky glow. But why struggle to find dim objects when there is so much to see on the big, bright object in front of you? The lunar crater called Tycho is best seen during a full Moon. Tycho was formed about 109 million years ago when an asteroid struck the Moon, leaving a crater over 50 miles in diameter and ejected dust trails that radiate out hundreds of miles in all directions. For more lunar highlights, go to
http://nightsky.jpl.nasa.gov/docs/ObserveMoon.pdf, a resource of the Night Sky Network.

Wednesday: Vega, the third brightest star visible from Ellensburg and the entire northern section of the United States, is nearly straight overhead at 9 p.m.

Thursday: The Sun is finally moving out of it period of having few or no sunspots. But while the Sun was inactive, astronomers were studying sunspots on other stars such as Corot-2a, a star that is similar to the Sun but much younger. Astronomers noticed that the brightness drop of Corot-2a was slightly different every time its planet Corot-2b passed in front of it. They thought it should be the same since the same planet was passing in front of it. So, the astronomers concluded the variation in brightness was due to sunspots on Corot-2a. For more information about this, go to http://www.skyandtelescope.com/news/home/49444867.html.

Friday: Jupiter is two fists above the east-southeast horizon at 11 p.m. It is about a fist to the right of the Moon.

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

Saturday, August 7, 2010

The Ellensburg sky for the week of 8/14/10

What's up in the sky 8/14/10

Today: It’s a moonless August morning. The first remnant of dawn has not appeared yet. Suddenly, you notice a large softly radiant pyramid of light in the east sky. The base of this ghostly triangle is along the east horizon and the peak stretches two or three fists held upright and at arm’s length above the horizon about two hours before sunrise. Don’t be scared. It’s not really a ghost. It is an effect called the zodiacal light. This light comes from sunlight reflecting off dust grains in our solar system. The effect is the most visible when the band of constellations called the zodiac makes a steep angle with the horizon. You need a clear dark sky with no haze or light pollution to see the zodiacal light. At its brightest, the zodiacal light rivals the light of the central Milky Way. This is one of the best times of year to see the zodiacal light in the morning.

Sunday: Mars, Venus, and Saturn are close together low in the western sky all week. Venus is by far the brightest of the three planets. It is a half a fist held upright and at arm’s length above the west horizon, a little bit south of west, at 9 p.m. Mars is about a finger’s width to the upper left of Venus and Saturn is less than a fist to the right of Venus.

Monday: It’s time to sing along with a holiday classic: “Oh, the weather on the Sun is frightful. But the aurora is so delightful. Well, the Sun is active and hot. Let it spot, let it spot, let it spot.” The Sun seems to finally be waking up from its sunspot slumber. On August 1st, the sunspot region 1092 triggered a huge coronal mass ejection (CME) that shot out from the Sun at a speed of more than 600 miles per second. A CME is plasma consisting mainly of electrons and protons. When these charged particles interact with the Earth’s magnetic field, they produce the colorful phenomenon known as the aurora. Basically, increased solar activity means a more active Sun which produce more CME which leads to increased aurorae.

Tuesday: Antares is about a finger’s width to the lower right of the Moon at 9 p.m.

Wednesday: Mars is still about a finger’s width from Venus and a half a fist above the west horizon at 9 p.m. But notice that they have both moved eastward away from Saturn with Venus having moved a little more.

Thursday: This evening, Venus is as far away from the Sun in the sky as it will get this orbital cycle. What is this "farthest away" point is known as the planet’s greatest eastern elongation. As you have noted all week, Venus is a half a fist above the west horizon at 9 p.m. Over the next two months, Venus will move toward the Sun in the sky. By the end of September, it will be lost in the glare of evening twilight.

Friday: Fomalhaut, the bright star in the Piscis Austrinus, the Southern Fishes, is about one fist above the southeast horizon at midnight. It is the southernmost bright star visible from Ellensburg and other locations near 47 degrees north latitude.

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