Tuesday, January 26, 2010

The Ellensburg sky for the week of 1/30/10

Saturday: Last February’s “Hot Topic” for the International Year of Astronomy is the Solar System. Even though the International Year of Astronomy is over, the Solar System lives on. Galileo’s discoveries about the Sun, the Moon, Venus, and Jupiter helped move us from a privileged spot in the center of the perfect heavens to one of billions of planets in the turbulent neighborhood known as the Milky Way Galaxy. Some may say that makes them feel small and insignificant. I say it makes me feel empowered. All those planets and very few, perhaps only one, inhabited by beings with the capability to comprehend their surroundings. It is better to understand your situation as one in a billion than to blindly and incorrectly think you are at the center of everything. Go to http://astronomy2009.nasa.gov/topics_feb.htm for more information about the Solar System. Go outside and look three fists held upright and at arm’s length above due east for more information about Mars.

Sunday: The good news is the days are getting longer and the nights are getting shorter. The better news is the farther north you go in the United States, the longer the days get. Here in Ellensburg, there is one more hour of daylight than on the first day of winter. In the southern part of the US, there are only 30 more minutes of sunlight. Of course, on the North Pole, the day length goes from zero hours to 24 hours.

Monday: Jupiter is about a half a fist above the west-southwest horizon at 6 p.m. In less than two weeks, it will be lost in the glare of the setting Sun.

Tuesday: Today is Groundhog Day. If Punxsutawney Phil doesn’t see his shadow this morning, he is telling us that he follows the Chinese calendar and that spring starts early. On the Chinese calendar, equinoxes and solstices occur in the middle of their respective seasons. In order for the vernal equinox to occur in the middle of spring, spring must start on February 3 or 4, depending on the year. Thus, if Phil doesn’t see his shadow, spring may start on February 3 or 4 as on the Chinese calendar. If Phil sees his shadow, he is telling us he agrees with the western calendar and that there will be six more weeks of winter meaning spring will start near March 20.

Wednesday: Saturn is two fists above the east-southeast horizon at 11 p.m.

Thursday: Earlier this month, NASA’s Wide-field Infrared Survey Explorer, or WISE, spotted its first of many never-before-seen near Earth asteroids. While there is no danger of this asteroid hitting Earth in the foreseeable future, the United State’s government is worried about the threat of a rogue asteroid hitting Earth. So much so that Congress mandated that by 2020, NASA must find 90% of all potential Earth-impacting asteroids down to 140 meters across. I may write a book about this search called “Going Rogue – An Asteroid Life”. Here is an excerpt.
I’d rather stand in front of one of Obama’s death panels than be in the path of even a small asteroid streaking towards Earth. Would it be dangerous? You betcha! The asteroid that created the mile-wide impact crater in Arizona was only 25 meters in diameter and packed a wallop about 150 times the force of the atomic bomb dropped on Hiroshima. I say “Thanks but no thanks” to that kind of risk, even if this size impact occurs only once every few hundred years.

Friday: This morning’s last quarter Moon is in the constellation Libra, the scales of justice. Libra is the only zodiac constellation to represent an inanimate object.

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

Wednesday, January 20, 2010

The Ellensburg sky for the week of 1/23/10

Saturday: Draco Malfoy makes an appearance in all seven books of the Harry Potter series. Perhaps you’ve heard of these. But, the constellation Draco the dragon makes an appearance in the sky every night. It is a circumpolar constellation as viewed from Ellensburg meaning it never goes below the horizon. The head of the dragon is one fist held upright and at arm’s length above due north at 9 p.m. Eltanin, the brightest star in the constellation, is at one corner of the trapezoid-shaped head of Draco.

Sunday: The moon is putting the moves on seven sisters tonight. Oh, he’ll try everything. Stretch and try to put his arm around the sisters. Stop short. Use lame pick-up lines such as “Hey baby, what’s your sign?”. At 7 p.m., the open star cluster called the Pleiades, or the seven sisters, is about a half a fist to the left of the moon. As the night progresses, the Moon will get closer and closer to the seven sisters in the sky. But, alas, they never meet.

Monday: Jupiter is one fist above the southwest horizon at 6 p.m.

Tuesday: Saturn is one fist above the east horizon at 11 p.m.

Wednesday: At 11 a.m., Mars will be closer to Earth than any other day for 2010 and 2011, a miniscule 62 million miles away. Currently, the northern hemisphere of Mars is angled toward Earth. Since it is springtime on Mars, people with small to medium-sized telescopes, six inches and larger, should be able to see Mars’ northern polar icecap shrink as Martian summer arrives. It will look like a white dot at the top of Mars. (Or, the bottom of Mars if your telescope inverts the image.) Mars is three fists above due east at 8 p.m.

Thursday: Are you interested in participating in astronomy research? You don’t need to go back to school. You don’t need to spend thousands of dollars getting a fake degree from an online university. The scientists working on the High Resolution Imaging Science Experiment, or HiRISE, camera on NASA's Mars Reconnaissance Orbiter would like your input on which objects they should target for close-up pictures. While you may think the scientists are just trying to build interest in their project by having people look at pretty pictures, there is a real scientific benefit to having many eyes searching for interesting targets. There aren’t enough scientists to carefully inspect all of the low power images. And, surprisingly, computers are not nearly as effective as people in making educated judgments of images. So, go to http://www.uahirise.org/ and click on the HiWish button. You’ll be on your way to suggesting close-up targets for NASA's Mars Reconnaissance Orbiter.

Friday: Mars is at opposition tonight. No, that doesn’t mean that Mars refuses to eat his peas. (Please eat your peas, children.) Opposition means that Mars is on the opposite side of the Earth as the Sun. An object is in opposition when it is due south 12 hours after the Sun. When an object is in opposition, it is at its highest point in the sky during the darkest time of the night. A planet in opposition shines brighter and appears larger in a telescope than any other night. And since Mars is also relatively close, it is exceptionally bright tonight. Mars is six and a half fists above due south at midnight.
Mars isn’t the only “biggest of the year” celestial object in the sky tonight. The Moon is at its closest position to Earth this month, also known as perigee. Since perigee happens only three hours after the full Moon, to turns out that tonight’s is the biggest full moon of the year. The Moon will look 13% bigger and 30% brighter than the most distant full Moon of the year, in August.

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

Tuesday, January 12, 2010

The Ellensburg sky for the week of 1/16/10

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: Jupiter is about a half a fist to the left of the Moon at 6:30 p.m. They are one fist above the west-southwest horizon.

Monday: Sometimes objects we can observe every day provide very difficult scientific questions. The star Epsilon Auriga is star that varies in brightness for a two year period every 27 years. Scientists were not sure of the exact cause of this dimming, the most recent of which started last summer. But recent images from NASA’s Spitzer Space Telescope, which sees infrared wavelengths, are helping scientists solve the puzzle. The bright star in the Epsilon Auriga system is orbited by another star which is surrounded by a huge cloud of sad grain-sized particles. This cloud, which is approximately the size of Jupiter’s orbit in diameter, causes Epsilon Auriga to be only half as bright. You can follow the cycle with the naked eye. Epsilon Auriga is about a fist to the upper right of Capella, one of the brightest stars in the sky. Capella is seven and a half fists above due east at 8 p.m.

Tuesday: Mars is three fists above due east at 9 p.m.

Wednesday: Saturn is one fist above the east horizon at 11:30 p.m.

Thursday: 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.

Friday: Friday: Spica, the brightest star in Virgo, is three fists above the south horizon at 6 a.m.

Wait a minute. We got all the way to the end of the week with no Moon phase summary? How can that be? There are 29.5 days between the same Moon phase in two different cycles. That means about 7.5 days between the phases new, first quarter, full and last quarter. Since a week is seven days, there are some weeks in which none of the main phases occur. This week, the Moon was always in the waxing crescent phase.

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

Thursday, January 7, 2010

The Ellensburg sky for the week of 1/9/10

Saturday: The ringed planet, Saturn, is making its way into the evening sky. It is about a fist held upright and at arm’s length above the east horizon at midnight. Its famous rings don’t look as spectacular because we are looking at them nearly edge on.

Sunday: Jupiter is one and a half fists above the southwest horizon at 6 p.m.

Monday: Antares is about a pinky’s width to the upper right of the Moon at 7 a.m. They are in the southeast sky. If you think a pinky’s width is close, talk to someone in Boston at this time. In the far northeastern corner of the United States, northeast of a line from Boston, through Vermont, and into New York, the Moon will pass between the Earth and Antares leading to an occultation of Antares. You can follow the Moon-star pair in Ellensburg even after sunrise as Antares will stay in the same relative position for the next few hours. By then you’ll need binoculars.

Tuesday: This morning take the M-M challenge. No, not the M&M challenge. Nothing will melt in your mouth. And not the Eminem challenge either. You’re not Slim Shady, no, you’re not the real Slim Shady. I mean the Mercury-Moon challenge. Mercury is one fist to the left of the Moon at 7 a.m. They are less than a half a fist above the southeast horizon. Because of the rising Sun, it will be a challenge to see both M objects.

Wednesday: 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.

Thursday: Tonight’s Moon is new. Don’t bother looking for it. The new moon is the phase where the Moon is directly between the Earth and the Sun. Hence the side of the Moon facing Earth is not receiving any sunlight and cannot be seen. But if you live anywhere from central Africa to east Asia, you will see the effects of the new Moon: it will block part of the Sun. Most of the people in that region will see a partial eclipse. Depending exactly where you live, the Moon will take a “bite” out of the Sun varying from a tiny nibble to a “you almost took my fingers off” giant bite. The lucky few who live along a 200 mile wide path from central Africa to east Asia will see an annular eclipse.
Despite the word similarity, annular does not mean once a year. Annular means “ring-shaped”. An annular solar eclipse occurs when the Moon, as seen from Earth, is not large enough to cover the Sun even then they are perfectly lined up. We sometimes have total solar eclipses and sometimes have annular solar eclipses because the Moon is not always the same distance from the Earth and the Earth is not always the same distance from the Sun.
Here is the difference between a total solar eclipse and an annular solar eclipse. Take a coin out of your pocket. Close one eye. Hold the coin close to your open eye such that you completely cover a round object across the room. This represents a total eclipse of that object. Now, slowly move the coin away from your eye until you can see an outline of the round object. This is an annular eclipse of that object. Your coin, representing the Moon, has too small of an angular size to completely cover the round object across the room, representing the Sun.

Friday: Mars is three fists above due east at 9 p.m.

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