SEPTEMBER  2011

SEPTEMBER STAR MAP | STARWATCH INDEX | MOON PHASE CALENDAR

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785    SEPTEMBER 4, 2011:   I Felt the Earth Move Under My Feet

“I feel the earth move under my feet; I feel the sky tumbling down—tumbling down.” Carole King’s hit pop tune of 1971 couldn’t have said it better. An earthquake and a hurricane in just one week might make anyone’s “heart start to trembling.” Hurricane Irene would have only been a minor glitch to Floridians and others along the Gulf Coast. Likewise, Californians must have also been snickering at the 5.8 magnitude quake that “rocked” the East Coast while the stresses of the really big West Coast quake continue to build beneath their feet. I was at my computer in my study when the quake swayed through around 2 p.m. on Tuesday, August 23. I distinctly felt a sideways motion first, followed by a lunge. The whole episode lasted maybe five seconds, but it had the effect of creating a little nausea in my stomach. Perhaps 30 seconds before becoming aware of the trembler, the house began making odd creaking noises that caught my attention enough for me to stand up and try to determine a direction. Seconds after sitting down and resuming work, my chair did its little do-si-do. What amazed me about this trembler was that it emanated from over 200 miles away, and I felt it. Several hours later, I learned that people along the entire East Coast felt it as well. The Midwest and eastern Canada shook too. West Coast quakes, although more destructive, are felt over very small distances because of a softer, more absorbent bedrock that dampens the surface ground vibrations that are created during a seismic event. The huge number of faults, weak crustal cracks, positioned at the boundary of the North American and the Pacific plates, also help absorb surface motions when a West Coast quake happens. The East Coast is not at a plate boundary, and it is composed of harder, more rigid rock. When it shakes, it rings like a bell, sending its “notes” far and wide for multiple hundreds of miles.

The Mineral, Virginia earthquake was felt all along the US East Coast as this USGS map testifies.

786    SEPTEMBER 11, 2011:   Remembering Sirius

I remember precisely where I was, driving east on Turner St., just beyond West Park when I heard about the World Trade Center. By the time I had reached Dieruff HS, teachers were scrambling to set up a TV in the library, and some students were beginning to gather. Formal instruction stopped, but education continued as all of us watched the towers crumble. I remember feeling isolated in a room filled with kids who were now contemplating uncertain futures. The hallway prattle of happy students was muted that day, as well as the lives of nearly 3000 Americans, including the son of an elementary teacher in my District. Trying to cope with what had happened, even one decade later, is still not easy, but one victim has helped to create a memorial which I can see in the sky. One of the deaths was a bomb detection dog named Sirius. Sirius, also called the Dog Star, is the brightest luminary of the nighttime sky and of Canis Major, the Big Dog. It can be seen at 5:30 a.m., low in the southeast against a brightening sky. Follow the three belt stars of Orion downward to connect with Sirius. You might ask, why memorialize a dog? A well-kept dog loves his master unconditionally and will instinctively sacrifice his own life if the situation merits. A dog is unconcerned about his owner’s race or religious beliefs. It is a type of bonding, a type of caring that we more sentient humans many times fail to grasp. Sirius died in his kennel when the North Tower fell. There just was not enough time to rescue everyone. Sirius the star is currently rising and will be visible in our sky until April of next year. The ancients considered heavenly bodies that were ascending to be good omens. They were refreshed, fed, and watered from their long journey beneath the Earth. At least for me, Sirius, the dog, and Sirius, the Dog Star, will serve as a beacon of hope for a better future world.

Sirius, The Dog Star is in the SE by dawn's early light, around 5:30 a.m. Map by Gary A. Becker using Software Bisque's, The Sky.

787    SEPTEMBER 18, 2011:   Follow the Moon

The waning moon this week provides a beacon of light to assist in finding other bright luminaries and a planet in the dawn sky. Since the moon is well past full and will be at last quarter on Tuesday—half on, half off—the light to the left, Luna will be visible to early risers who normally watch the sky brighten through kitchen windows as they are having breakfast. They will only have to pop outside and find the moon which will help to identify the other bright celestial bodies nearby. Start right away on Sunday morning with the moon only six of its diameters south of the sparkling blue Pleiades. Use binoculars to “scope” out the brightest stars of the finest open cluster in the heavens just above the moon. Both the moon and the Pleiades will fit in the same field of view. Monday morning finds the moon above and to the left of the bright star, Aldebaran, the orangey eye of Taurus, the Bull. Wide field binocular will again show both objects in the same field of view. Over the next three nights the moon silently glides towards a near rendezvous (Sept. 22) with Gemini’s brightest luminaries, Caster and Pollux (above and slightly left), red Mars (left and slightly below) and Procyon of Canis Minor the Little Dog (below and slightly right). All of this takes place mid-sky in the ESE. Orion, the Hunter, and Sirius, the brightest star of the night, gleam to the moon’s right. Don’t forget the autumnal equinox on Friday, September 23 at 5:06 a.m. when it’s goodbye to summer and hello to the cooler days of fall. At that moment the sun will be crossing the Earth’s equator and heading into the Southern Hemisphere. Down Under, it will be spring. The moon on that morning will have slid below Mars as a thinning crescent and again present a lovely view to the unaided eye or through low power binoculars. By Sunday Luna is below Regulus in Leo, near the horizon at 6:00 a.m. Good celestial hunting.

788    SEPTEMBER 25, 2011:   Well Hello, Mira

Variable stars can change in their light output because another star eclipses or is blocked by the primary star. Changeable outputs of energy from a star can also result from instabilities within its energy producing core. These types of intrinsic variations happen when a star is just beginning to shine or near the end of its life. In either case the star’s core is readjusting to changes in the density, pressure, and temperature of its gases. Very old, red giant Mira, or Omicron Ceti, in the star pattern of Cetus the Whale is such an intrinsic, long period variable. Its name comes from the same root as miracle, and it means “the amazing one.” And amazing it is, because for most of its 330-day period, it is invisible to the unaided eye. Then it brightens from invisibility to a star that is about as luminous as any star in the Big Dipper. Mira is reaching its peak brightness right now in a part of the sky that is normally so bland that the average person rarely takes notice of it. Enter Jupiter, which is nearby and another star Menkar, below Jupiter, which is much fainter, but easily seen. Jupiter, Menkar, and Mira form a near isosceles triangle with the wider base created by Jupiter and Mira. Viewing Mira gives us a six billion year glimpse into the future history of our sun, when it will become a bloated, red giant star, perhaps even swallowing Earth and losing its outer layers to the interstellar medium. Mira is doing just that as it leaves a tail of debris behind it which is 15 light years in length. Although Mira rises about 9:30 p.m., give it at least three to four hours of time to get high enough to be easily seen. By 1:30 a.m., it is just east of south. Look for bright Jupiter slightly above mid-sky in the SE. With binoculars scan below and slightly left of Jupiter for Menkar; then look to see if it is visible to the unaided eye. Going the same distance to the left and slightly lower will be Mira. An online map is available for reference.

Finding long period variable, Mira Ceti, among the dim constellations of autumn will be easy with the help of brilliant Jupiter. Jupiter, Menkar, and Mira create an isosceles triangle with the wide end joining Jupiter and Mira. Even with the horrendous weather the East Coast has been experiencing, I have seen Mira twice, both with the unaided eye. In late September it was just several tenth of a magnitude fainted than Menkar. Map by Gary A. Becker using Software Bisque's, The Sky.