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Homecoming, the Fall Sky, and Two Exciting Discoveries

By: Dr. John Smetanka
Posted Fri., October 5, 2012

This is Homecoming and Fall Family Weekend at Saint Vincent College. We will host a number of events as we welcome to campus alumni and the families of current students. A full schedule of events is available here. Included in those events are four planetarium shows from 5pm to 7pm Saturday afternoon. If you are on campus please join us in the Angelo J. Taiani Planetarium and Astronaut Exhibit. Our newest show, Dynamic Earth, will be presented at 5pm and 6pm, The Sky Above Mr. Roger’s Neighborhood at 5:30pm, and Oasis in Space at 6:30pm. If you cannot be at Homecoming and Fall Family Weekend, we have public shows on the second Saturday of each month at 11am with a showing of The Sky Above Mr. Roger’s Neighborhood at 12:30pm. A schedule of events is available on the Planetarium web page.

October is one of the best months for stargazing. The constellations of the summer sky are gradually moving westward giving way to a new group of constellations we have not seen since last winter. Perseus, Andromeda, Cassiopeia, and Pegasus are rising along the eastern horizon this month in the early evening. The sky chart below provides a map to find the constellations in the evening sky. 

Fall 2012 Evening Sky
















Unlike stars which remain in the same relative position, planets wander through the celestial sphere moving along the ecliptic (the same path as the sun), occasionally stopping and retracing their path. We know today that this peculiar motion is due to Earth passing the other planet as both planets orbit the sun. Retrograde motion, as the backward movement on the sky is called, is the characteristic which set planets apart from all other celestial objects.

Last year you might recall Venus and Jupiter graced the winter evening sky. This season it is the morning sky that has the brightest two planets. If you are up to observe the predawn sky you will see these two planet shining brilliantly with Jupiter almost directly overhead and Venus preceding the rising Sun in the East. Also visible will be the winter constellations, Orion, Gemini, Taurus, and Auriga.Fall 2012 Morning Sky  





















Last week two exciting discoveries were made. NASA’s Curiosity rover sent images that fairly conclusively show that water once flowed in streams on the surface of the red planet. The photo below shows easily recognizable features of a dried stream bed, including rounded pebbles and an undercut bank.

Mars Streambed The other exciting discovery comes from Russia. There, two astronomers detected a faint comet, Comet ISON, between the orbits of Jupiter and Saturn that will fall into the inner solar system passing within two million miles of the sun at the end of next year. Comets are basically dirty snowballs, objects made of frozen water and gasses mixed with rock and dust. They are remnants of the disk of material that coalesced to form the sun and planets. The progenitors of comets typically orbit the sun in the outer reaches of the solar system. Occasionally, the gravity of another object, perhaps one of the outer planets, will nudge one of these dirty snowballs and it will begin to fall toward the sun. As it nears the sun it will begin to melt and create a vast debris cloud behind it that can be millions of miles long – a comet. Reflected sunlight results in a beautiful bright nucleus with a long tail pointing away from the sun. While predicting the eventual brightness of comets is inherently uncertain, this one has the potential to be one of the brightest comets in centuries – some predict as bright as a full moon. Comet ISON is following an orbit similar to the Great Comet of 1690 which is depicted below in a painting by Lieve Verschuier of the sky over Rotterdam. Unlike some of the most recent bright comets, Comet ISON will be visible to observers in the northern hemisphere, that is, if Comet ISON survives its close encounter with the Sun - stay tuned! 
Great Comet of 1690 


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Dr. John Smetanka,
Academic Affairs

Dr. John J. Smetanka has been a member of the full-time faculty since 1997 and currently serves as the Vice President for Academic Affairs and Academic Dean of Saint Vincent College, a position he has held since January, 2008.