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Jjmonl 1612.Pmd alactic Observer GJohn J. McCarthy Observatory Volume 9, No. 12 December 2016 Water - the elusive elixir of life in the cosmos - Is it even closer than we thought? The John J. McCarthy Observatory Galactic Observer New Milford High School Editorial Committee 388 Danbury Road Managing Editor New Milford, CT 06776 Bill Cloutier Phone/Voice: (860) 210-4117 Production & Design Phone/Fax: (860) 354-1595 www.mccarthyobservatory.org Allan Ostergren Website Development JJMO Staff Marc Polansky It is through their efforts that the McCarthy Observatory Technical Support has established itself as a significant educational and Bob Lambert recreational resource within the western Connecticut Dr. Parker Moreland community. Steve Allison Tom Heydenburg Steve Barone Jim Johnstone Colin Campbell Carly KleinStern Dennis Cartolano Bob Lambert Route Mike Chiarella Roger Moore Jeff Chodak Parker Moreland, PhD Bill Cloutier Allan Ostergren Doug Delisle Marc Polansky Cecilia Detrich Joe Privitera Dirk Feather Monty Robson Randy Fender Don Ross Randy Finden Gene Schilling John Gebauer Katie Shusdock Elaine Green Paul Woodell Tina Hartzell Amy Ziffer In This Issue "OUT THE WINDOW ON YOUR LEFT"............................... 3 COMMONLY USED TERMS .............................................. 17 TAURUS-LITTROW .......................................................... 3 EARTH-SUN LAGRANGE POINTS & JAMES WEBB TELESCOPE 17 OVER THE TOP ............................................................... 4 REFERENCES ON DISTANCES ......................................... 17 INSIGHT INTO CATACLYSMIC PLANETARY IMPACTS ............... 4 INTERNATIONAL SPACE STATION/IRIDIUM SATELLITES .......... 24 SHADY SIDE OF SPACE ..................................................... 6 SOLAR ACTIVITY ........................................................... 24 STILL ACTIVE AFTER ALL THESE YEARS ............................ 6 IMAGE CREDITE ............................................................ 18 RETURN TO THE COLUMBIA HILLS? .................................. 6 SECOND SATURDAY STARS ............................................... 19 UPDATE ON SCHIAPARELLI ............................................... 7 BENEATH THE CLOUD DECK ............................................. 7 A PERIGEE MOON .......................................................... 8 SPACESHIP EARTH ........................................................... 9 PURCHASING A TELESCOPE ............................................... 9 DECEMBER HISTORY ...................................................... 11 DECEMBER NIGHTS ....................................................... 13 SUNRISE AND SUNSET ...................................................... 13 ASTRONOMICAL AND HISTORICAL EVENTS ......................... 13 2 Dec 2016 http://www.mccarthyobservatory.org “Out the Window on Your Left” T’S BEEN 44 YEARS since nauts Cernan and Harrison Schmitt The Taurus-Littrow valley was we left the last footprint on the (geologists by training) set their selected for the last Apollo mission Idusty lunar surface. Sadly, as a lander down in a valley amid sev- due to its varied geology. From nation founded on exploration and eral large, rounded mountains flyovers of the valley from orbit the conquest of new frontiers, we (massifs) that were actually blocks and the darkened halos observed appear to have lost our will to lead of the lunar crust thrust upward by around valley craters, scientists as a space-faring nation. But, what the initial basin-creating impact. were hopeful that site might con- if the average citizen had the means Several hundred million years tain a relatively young volcanic to visit our only natural satellite; later, magma from deep within the vent. While no vent was found, Moon erupted, flooding the basin Harrison Schmitt did find “orange through fractures in the underlying soil” on the rim of a 46 foot deep rock. Multiple eruptions darkened (14 meter) impact crater named the surface while with each torrent Shorty. The orange in the soil was of lava the basin slowly filled, cre- found to be titanium-rich volcanic ating the relatively smooth surface glass from an ancient fire fountain. seen today. The glass had been buried beneath Taurus Littrow what would they see out the win- dow of their spacecraft as they en- tered orbit around the Moon? This column may provide some thoughts to ponder when planning your visit (if only in your imagination). Shortly after midnight (EST) on December 14, 1972, Apollo 17 as- tronaut Gene Cernan drove the Lunar Rover Vehicle to its final parking spot so that its camera could record the Lunar Module’s upper stage ascent to orbit and ren- dezvous with the Command Mod- ule. He then knelt down and traced his nine year old daughter’s initials “TDC” in the lunar dust, knowing that, in the absence of weather, Tracy’s initials could remain undis- turbed for eons. With Cernan climbing back aboard the Lunar Module, manned exploration of the Moon came to an abrupt end. The Apollo 17 landing site is along the southeastern rim of the Serenitatis impact basin, created 3.8 to 3.9 billion years ago. Astro- http://www.mccarthyobservatory.org Dec 2016 • 3 lava flows for billions of years until excavated by the Shorty-forming impact. The low Sun angle in the Tau- rus-Littrow photo accentuates low profile features. Contraction of the basaltic lava layers as they cooled formed ridges in the lunar mare. Dorsa Smirnov is a segment of a 300 mile (500 km) long serpentine ridge along the shore of Mare Serenitatis. Over the Top NASA’s Cassini spacecraft is now in a polar trajectory as it pre- pares for its final series of orbits dubbed the “Grand Finale.” The polar orientation provides a unique perspective of the gas giant, its poles and ring system. In this view, Saturn’s six-sided polar jet stream, known as “the hexagon,” is fully il- luminated. The hexagon is an im- mense hurricane rotating around the planet’s north pole with an eye 50 times larger than a comparable Image Credit: NASA/JPL-Caltech/Space Science Institute terrestrial hurricanes. The clouds near the center are spinning coun- planet. A similar storm encircles the planet’s north pole. The space- terclockwise (from this vantage Saturn’s south pole. craft was approximately 1 million point) at speeds in excess of 340 mph The image (above) was taken miles (2 million km) from Saturn (547 kph), almost twice as fast as the looking down on the gas giant and when the image was acquired. Insight into Cataclysmic Planetary Impacts NASA launched twin spacecraft by the spacecraft is still being change to Orientale’s original into lunar polar orbit in Septem- mined for insight into the Moon’s basin’s structure (exemplified ber 2011. For almost a year, the formation and its history of by the characteristic multi-ring, GRAIL spacecraft (named Ebb and massive impacts by asteroids, com- bullseye pattern). At mission’s end, Flow) flew in formation on an ets and other proto-planet debris. the orbit of the GRAIL spacecrafts identical track over the lunar land- Two new papers have been pub- was lowered from a nominal scape. Minute change in the lished on the formation of the altitude of 30 miles (50 km) to less distance between the two space- Orientale impact basin, located on than 1.2 miles (2 km), for a closer craft (either moving slightly closer the Moon’s southwestern limb (as look at Orientale, since it exempli- or further away from one another) viewed from Earth), using GRAIL fied large impact basins through- as they passed over areas of differ- data. The basin, 580 miles (930 out the solar system. ent density (caused by mountains, km) across, was created approxi- The first paper examined the craters or subsurface formations) mately 3.8 billion years ago. relationship of the impact rings with enabled scientists to create an Unlike other basins on the Moon the size of the initial impact crater. accurate map of the Moon’s gravi- that have been concealed by lava The GRAIL gravity field data indi- tational field. While the mission flows or degraded by subsequent cated that the impactor that created ended in 2012, the data collected impacts, there has been little the Orientale basin excavated at least 4 Dec 2016 http://www.mccarthyobservatory.org 816,000 cubic miles (3.4 million up blocks of rock. The inner ring is the remnants of the “central peak” cubic km) of rock, producing a theorized to have been formed from after its collapse. crater with a diameter somewhere in size between the two inner impact rings. The crater quickly collapsed as the Moon’s surface rebounded from the impact. The second paper addressed the formation process for the impact rings. Simulations correlated with the GRAIL data suggest that the rings (at least the outer rings) were produced by the collapse of s ub-surface structures due to the energy imparted by the impactor (the impactor, was estimated at 40 miles (64 km) across and was likely traveling at 9 miles a second (14 km/s) when it collided with the Moon). The ring-shaped faults and scarps that define the outer rings are theorized to have been formed Mare Orientale (circles defining impact rings added). The colors by the subsidence of the mantle, represent the strength of the moon's gravity field with red indicating heated by the impact, which frac- areas of higher gravity, or excess mass, and blue indicating lower tured the overlying crust, thrusting gravity or areas of mass deficits. Image credit: Ernest Wright, first week after launch as the telescope travels to its observing position around the second Lagrange
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