Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.aaa.org/EyepieceFiles/aaa/2010_09_September_Eyepiece.pdf Дата изменения: Sun Feb 22 20:31:02 2015 Дата индексирования: Sun Apr 10 03:48:38 2016 Кодировка: Поисковые слова: п п п п п п п п п п п п п п п п п п п п п п п п п п п п п

Journal of the Amateur Astrono mers Association of New York September 2010 Volume 58 Number 9, ISSN 0146-7662

EYEPIECE
around other stars and transported to our solar system. Some CAIs are from meteorites whose parent bodies (asteroids) experienced aqueous (water -mediated) and ther mal (heating) chemical alteration. Other parent bodies experienced less alteration. Dr. Audrey Bouvier of Arizona State reported new measur ements of the absolute age of an unmelted CAI from the very unalter ed meteorite Vigarano thats 4568.7 ± 0.3 million years old. This pushes the oldest solar system age back a million years. Two colleagues r eported measur ements and a framework for deriving the true value for the primor dial lead isotopic composition of the solar system. This value is funda mental to interpreting all U-Pb isotopic ages. A long-standing problem in meteoritics involves the "missing mantles" of iron meteorites, for which at least 50 parent bodies are inferred from chemica l evidence. We have samples of the metallic cor es of the planetesima ls, so wher e are their silicate mantles? Ed Scott (University of Hawaii) a nd collea gues started a lively discussion with their provocative hypothesis of a "hit and-run collision." In grazing collisions, the sma ller of two protoplanets would be eviscerated, and mantles wouldnt survive. The evidence? S everal ir on-meteor ite groups recor d cooling rates inconsistent with cooling under a blanket of silica te rock. Instea d, these irons cooled rapidly, indicating their insulating silicate ma ntles wer e stripped off in collisions. More provocatively, main group pallasites (stony-ir ons) ma y represent partially-melted fractions of torn-apart planetesima ls wher e the metallic cor e ha d largely solidified. All of these processes occurred less than 10 million years after formation of CAIs, the oldest rocks known to have for med in the solar system. Conference continued on page 10

New York Meteoritical Conference Plumbs Primordial Rocks
By Denton Ebel
The 73rd annual meeting of the Meteoritical Society in New York July 26-30 featured more than 440 scientific abstracts, a new recor d for this meeting. Research results wer e described in a similar number of presentations. Topics included impact phenomena, planetary science, age deter minations for ancient rocks, organic material in the cosmos and meteorites, models for preplanetary disk processes, and all the ancient components that are incorporated into meteor ites, including pre-solar grains formed around other stars and incorporated into meteorites around the Sun. Meeting abstracts are at http://www.lpi.usra.edu/ meetings/metsoc2010/pdf/program.pdf. A pre-confer ence workshop, "Disks, Meteorites, Planetesima ls," orga nized by Dr. Mordecai-Mark Mac Low of the AMNH and two collaborators, brought together observers of disks around young stellar objects, modelers of the physics and chemistry of disk processes, and meteoriticists who study the solar systems earliest mineral grains and rocks, as well as pre-solar grains for med around other stars and incorporated in meteorites. A post-conference symposium, "Chondrules: Their Role in Early Solar System Histor y," organized by CUNYs Dr. Harold C. Connolly Jr. and a French colleague, reviewed new findings on the most abundant protopla netary rocky components of chondrite meteorites. Here are other confer ence highlights: Calcium-, Aluminum-rich inclusions (CAIs) in the most primitive chondrites record the earliest uraniumlead (U-Pb) ages of any rocks that have "solar" isotopic ratios of major elements, indicating they wer ent for med


What's Up
By Tony Hoffman The Sky for September 2010
King of the Planets. Jupiter comes to opposition September 21, when it will be at its brightest in nearly half a century. Jupiter is nearing the perihelion of its 12-year orbit, so its relative proximity ma kes it unusually bright. It will be closer to us than its been since 1963, though it will still be about 368 million miles away. The giant planet will blaze at magnitude -2.9 in Pisces, and show a disk just short of 50 arc seconds in dia meter. This will be an idea l opportunity to view Jupiters cloud belts and other atmospheric features. The planets south equatorial belt appeared to vanish earlier in the year, but is slowly regaining its visibility. Jupiters bright moons Io, Europa, Ganymede and Callisto change position over the course of an evening. When near the planet, or each other, their motion can sometimes be detected in a matter of minutes. This is also a good time to obser ve the transit of the moons and/or their shadows across Jupiters disk. As a bonus, Uranus comes to opposition the sa me night as Jupiter, just 1 degr ee away. A telescope at high power will reveal the outer worlds blue-gr een disk, 3.7 arcseconds across. Queen of the Evening. Venus blazes in the southwester n evening sky near its maximum brightness of ma gnitude -4.8. It starts the month in Virgo near Spica, not far from Mars. During the month, Venus and Mars mor e or less keep pace with each other as they pass into Libra. At magnitude 1.5, Mars is inconspicuous. Venus shines more tha n 200 times brighter than the Red Planet. Dawn Herald. Mercury puts in its finest morning perfor mance of the year this month. Visible starting around mid-month, when its around ma gnitude 0.5, the innermost world is at its highest September 19, when it brightens to ma gnitude -0.4. After that, even as it brightens, it slowly slips back into the dawn glare. By September 30 it shines at magnitude -1.1 in bright morning twilight. September 1 Last-quarter Moon at 1:22 p.m.; Venus lies 1.2 degr ees from Spica. September 4 Mars lies 2 degr ees from Spica. September 7 Moon is at perigee, 221,948 miles from Earth, 11:58 p.m.
2

September 8 New Moon, 6:30 a.m. September 10 Asteroid 8 Flora is at opposition. September 11 Moon lies near Mars and Venus. September 15 First-quarter Moon, 1:50 a.m. September 19 Mercury is at greatest elongation from the Sun (18 degr ees) in morning sky. September 21 Asteroid 6 Hebe is at opposition; Jupiter is at opposition; Uranus is at opposition. September 22 Autumnal equinox, 11:09 p.m. September 23 Full Moon, 5:17 a.m.; Moon lies near Jupiter; Venus is at greatest brilliancy. September 29 Venus lies 6 degr ees from Mars. September 30 Last-quarter Moon at 11:52 p.m.

Venus, Mars and Saturn In the Summer of 2010
By Joseph A. Fedrick
I went to the High Line near 14th Street and 10th Avenue the evening of July 27 and saw two telescopes set up, each with long lines of people waiting to see the planets. Creamy white Venus was low in the west and was brilliantly visible. Just above and to the left (south) was the pair of coral pink Mars and yellow Saturn. One scope, a 4-inch Schmidt-Cassegrain, was pointed at Venus. It appeared as a slightly mor e tha n ha lf-lit disk at around 100x. The other scope, a 10-inch reflector, was first pointed at Mars and then at Saturn. Mars appeared as a coral-pink, featureless tiny disk, while Saturn appeared as a pale, oblate, yellowish disk with faint brownish cloud belts and the shadow of the rings crossing the disk. The rings wer e a dusky tan and nearly edgeon. The ring shadow and belts wer e difficult to distinguish from each other due to the turbulent, unsteady air. The bluish stars Deneb, Altair and Vega from the Summer Triangle appeared as twilight faded into night. Yellowish Arcturus appeared high while reddish Antares was also visible much lower in the sky toward the south. I observed Saturn, Mars and Venus for m a spectacular triangle to my west around 9 p. m. August 6. August was 2010s last month for viewing Venus, Mars and Saturn in the evening. However, during August Jupiter began to rise well before midnight and should provide for some spectacular observations this fall.


A Message from AAA President Richard Rosenberg
Hello members: Im afraid this letter will be a little mor e serious than usual. Weve run up a significant deficit in the last year. Nevertheless, with your help we hope to avoid an increase in dues. How can you help? The answer is surprisingly simple. Most AAA members (more than 300) have Internet access but only 60 receive Eyepiece by e-ma il. It costs about half of our $25 membership fee to send the paper to members. Deliver ing Eyepiece by e-ma il costs nothing to you or to us. And ther es a bonus: For many articles weve added clickable links to websites providing mor e infor mation. If enough members comply we should be able to get through this troubled economy without raising dues. Of course, a donation, if you can afford it, would be gr eatly appreciated as well. Other changes are occurring. Dr. Gerceida Jones has agr eed to become chair of our seminar on Recent Advances in Astronomy, which will move to New York University (rent -fr ee). Its next meeting will be September 16. The Observers Group is being folded into seminar sessions. Seventeen people attended the dark-sky observing session at North-South La ke August 7. The sky was magnificent until clouds moved in shortly after 1 a. m. Next date is September 11. Dont have a ride? Dont know how to get ther e? Just got a new scope and dont know how to use it? We match riders with drivers and veterans with rookies. Well get your new scope working. Tony Hoffman and Tom Haeberle hosted a star party in Rego Park on July 19, and ther e will be another September 20. Another tha nk you goes to Joe Delfausse for leading an obser ving session at Fort Greene Park July 31 while I was out of town. Well be ther e again September 11. On October 1, the 2010-11 AAA lecture series will begin with a talk by Dr. Max Tegmar k of MIT on "The History of the Universe in One Hour." Talk about time travel! And dont forget Urban Starfest October 16 (cloud date 17th). Rich Rosenberg, president@aaa.org, (718) 522-5014

MIT Professor Kicks Off 2010-11 AAA Lecture Series October 1
Dr. Max Tegmark, professor of physics at MIT, will kick off the AAAs 2010-11 lectur e series on Friday, October 1 when he discusses "The History of the Universe in One Hour." The free public lecture will begin at 6:15 p. m. in the Kaufmann Theater of the AMNH. Other lectures in the AAA series are as follows: November 5, Micha el Tuts, Columbia University, "Particle Physics at the Large Hadr on Collider and Cosmology." Dece mber 3, Suzanne Young, University of New Ha mpshir e and NASA, "Top 10 Discover ies of the Phoenix Mission to Mars." January 7, Robert Nemir off, Michiga n Technological University, "Best Astronomy Pictures of the Day, 2010." February 4, Neil Weiner, NYU, "Illuminating Dark Matter." March 4, Andrea Dupree, Harvard-S mithsonia n Center for Astrophysics, "Searching for Extrasolar Planets with Kepler." April 1, Greg Matloff, New York City College of Technology, "Regr eening the Earth Using Space Resources." May 6, David J. Thompson, NAS A, "Exploring the Extr eme Universe with the F er mi Gamma-ray Space Telescope. " Duprees talk will be the clubs annual John Marshall Memor ial Lecture, which honors a past president and executive dir ector of the AAA who was instrumental in its growth. Marshall died in 1997.
3


Viewing the Southern Sky While in S. Africa for World Cup
By Stan Honda
In June I was in South Africa for the World Cup and had several gr eat astronomy experiences. Im a photographer with Agence France-Presse, the French wire service, and was sent ther e to cover the matches. I was assigned to photograph the Australian tea m (the "Socceroos"), which wer e staying and practicing in an area northwest of Johannesburg. My compa ny put me up at a bed and br eakfast in a fairly rural area. The first night I was ther e, I noticed how well I could see the Milky Way, although I was only 25 miles outside Johannesburg. The b&b proprietor told me about a "big NASA antenna" nearby that occasionally gave tours. On a map, I saw Hartebeesthoek Radio Astronomy, about 27 km from the b&b. Here are two entries from a blog I wr ote about the three weeks I was in South Africa [edited for space]. Tuesday, June 15 The Socceroos have a da y off, so no media availability. I went on a fascinating tour of the Hartebeesthoek Radio Astronomy Observatory (Hart RAO), about 30 minutes from the b&b. The original 26-meter antenna was built by NASA to track satellites, especially the early lunar probes. Its in a n ideal location: high altitude, dry climate. Its now used for astronomical research and also as a type of GPS with other radio telescopes to accurately detect movement of the continents. I missed the monthly Saturday public tour so I ema iled their Science Awareness Programme. Marion West, one of the r esident astronomers, agreed to give me a private tour. Her specia lty is the shell of expanding gas around an exploded star, something that will happen to our Sun in "5,000 million years," she says. The Hart RAO is a fairly basic facility in a relatively quiet area northwest of Johannesburg. The centerpiece is the big 26-meter antenna and there are several smaller antennas, all doing radio astronomy: detecting objects radio-wa ve emissions. So they can do obser ving 24 hours a day, since light and usually weather dont affect their obser ving.
4

But many things do affect the telescopes, mainly anything that emits any kind of fr equency, such as cell phones and microwa ves. So ther e are none of those at the site. Marion said often a car starting up can cause a glitch in their data. The creeping suburban sprawl of Johannesburg will have an effect in a few years, astronomers say. Marion rummaged around in a storage room and found a small-dish antenna, electronic box, lamp and extension cord. We took all this outside, wher e she demonstrated how various items emit radiation in the for m of radio wa ves. Its fairly low tech but effective. A school group was there at the same time; they have a pretty big visitor center with ma ny hands-on displays. In the control room for the big telescope, Marion showed me various instruments that looked like they wer e out of an NASA film of the ,,60s space program. In fact, they did date from the 60s when NASA built the telescope. Finding parts is difficult, such as tiny pens for graph paper and tiny inca ndescent bulbs for controlpanel lights. Marion also showed me a demonstration antenna for the Square Kilometre Array, a giant radio-telescope project that South Africa and Australia are bidding for. Its planned for the western region of South Africa and will have 10 times the sensitivity of Arecibo and 50 times the sensitivity of the Expanded Very Large Array. Total collecting area is expected to be 1 square kilometer. Friday, June 18 Had a great tour of the night sky from Sa m Rametse at Hartebeesthoek last night. Ther e was an over night school group and Sam, part of the Science Awareness Outreach Programme, was doing stargazing. The kids didnt want to go out in the cold, but Sam gave me a tour. Sam, who is black, talked about being black and needing good role models. Unfortunately there wer e few or none in a field like astronomy. He said kids want to be doctors because they see successful black doctors. He had been to New York once, and visited the Hayden. Sam proudly said he had met Neil deGrasse Tyson, head Viewing continued on page 12


The First Rock from the Sun Exudes Much New Information
By Evan Schneider
Six years ago, on August 4, 2004, a Boeing-built Delta 2 rocket lifted the Mercury MESSENGER spacecraft from Cape Canaveral to start a long circuitous journey taking it past Earth once, around Venus twice a nd around Mercury three times over a seven-year period just to position it for orbit insertion on March 18, 2011. On July 26, Dr. Sean C. Solomon, dir ector of the Carnegie Institution of Washingtons Department of Terrestrial Magnetism and principal investigator for the mission and a geophysicist, deliver ed the Barrington Invitational Lectur e at the AMNH to discuss the mission status and new infor mation thats changed our understanding of this small (5% Earth mass), dense planet. The lecture was a part of the 73rd annual meeting of the Meteoritical Society. Solomon outlined the history of Mariner 10s 1974 and 1975 passes, mapping 45% percent of Mercurys surface and obtaining the first up-close r eadings of magnetosphere characteristics, and MESSENGER (MErcury Surface, Space ENvironment, GEochemistry,and Ranging) filling in the balance of the topography with its multiple passes and ultimate orbit strategy. "The big debate," he stated, "is the potential aspect of early volca nism on the planet." Wher e Mariner 10 ima ges of the Caloris Basin wer e analyzed as depicting smooth plains with impact craters, MESSENGERs dating indicates younger exterior plains and older inner plains. If the craters wer e due to single-event impacts, the materials would date the sa me. Differ ences in age indicate impacts may have opened up the subsurface and filled craters with ma gma. More r ecent images indicate vents in the terrain (probably volca nic domes as on Luna Mare) and large radial ranges that would surpass the effect of any meteoric impact. Further evidence comes from the Rachmaninoff Basin, a double-ringed basin 300 km. across, first ima ged in MESSENGERs third flyby. Thanks to spectral imaging, the outer peak ring has been shown to have younger material than the interior ring. This is consistent with other for mations on Mercury, again supporting the volcanism perspective. Of particular inter est in new ima ges wer e lobate scarps. These are curved or scalloped-edged cliffs, some up to 1,000 km long and 3 km high, for med from fracturing, or faulting, when one portion of the surface was thrust up and overrode the adjacent terrain. Scientists also looked at high-relief ridges and wrinkle ridges. By comparing new ima ges with Mariner 10 images, Solomon could deduce that cratering exca vated buried material. These materials are possibly 4-5 kilometers below the surface and differ from volcanic flow plains. This potentially indicates an interlayer ed crust, something never before consider ed. MESSENGER is currently traveling between Mercury and the Sun, 30 million miles from the Sun. Its searching for asteroids (called vulcanoids, named after the hypothetical and disproven pla net Vulcan) orbiting the Sun inside Mercurys orbit. Daily updates on the s ta t us of t he c a n b e ob ta ine d a t ht tp:/ / messenger.jhuapl.edu/ . With the March 2011 orbit insertion a head, Solomon is already preparing an extended mission proposal. Meanwhile, the European Space Agency, in conjunction with the Japan Aerospace Exploration Agency, is preparing for the BepiColumbo mission to be launched in 2014, arriving at Mercury in 2020. In this mission, two spacecraft will travel to Mercury in a composite spacecraft and study Mercurys magnetospher e. The craft will also search for mor e signs of water ice in shadowed craters. The next big step in understanding Mercury would be getting a lander to the surface to do "the chemistry," Solomon said. The challenges are great, given the difficult ther mal environment on the da yside and the lack of solar-power availability on the nightside. "What will we do with the data?" Solomon asked. "We need a lab for how a planet works. We need a set of rules that apply to all inner planets. Then, we can apply these physical and chemical laws to other planets." In summary, the speaker ma de an understatement: "Mercury is not what we thought it was only two and a half years ago."
5


Review: Manned Space Travel, Robotic--or a Third Way?
By Luis Marcelo Cabrera
Technology, Evolution and Interplanetary Travel is the subtitle of "Robots in Space" by Roger D. Launius and Howard E. McCurdy (Johns Hopkins, $35), and it really covers all those topics--a nd mor e. The authors do an excellent job of chronicling the politics, history and world events surrounding the controversy of ma nned vs. robotic space exploration. They ma ke a very convincing case about not using the ter m unma nned mission, since ther es still need of huma n operators controlling the ma chines. Hence the mor e appropriated ter m, robotic. Since the dawn of the space age, adher ents of two lines of thought have argued their case to the public, officials and scientific institutions. Some proponents have switched sides at times and whenever one group seemed to prevail, the other recover ed its stance. Launius and McCurdy go into exquisite detail tackling the pros and cons of both sides, taking care not to side with one option. When I started r eading the book, my mind was set in favor of robotic missions, by the middle of the book I was uncertain about the optimal path and now my mind is inclined towards a solution mor e appropriate for a science-fiction book. Five deca des ago, space exploration was mainly a subject of science fiction and now it per meates science in ever y discipline, so it shouldnt sound too farfetched that my final thoughts after reading this book are more in line with ideas developed by Isaac Asimov and the like. The book covers policy changes at NASA and the evolution of public expectations regarding the space program. When the Moon race started, most of us viewed robots as science-fiction machines incapable of perfor ming the simplest tasks without huma n intervention. Later on that vision changed, aided by the adva nces in electronic components and the successes of earlier robotic probes. Toda ys robotics are far mor e advanced, lighter and compact, but still incapable of running completely by themselves. Humanity is vigorously stepping up efforts to find
6

worlds similar to our own. If we other Earth in the near future, the better explor e it will spark and ther sensus about how to achieve such a

wer e to discover andebate about how to e seems to be no confeat.

Human limitations are clearly exposed in the book, including endurance, limited lifespan, hostility of outer space and the necessity of carrying with us a friendly environment. It also delineates limits current technology imposes on space exploration, such as the necessity to anticipate and program for ever y situation. As missions target celestial bodies further away and include exploration of their surfaces by rover vehicles carrying laboratories, it becomes critical that machines have a higher level of self reliance and an ability to act between the hours or days it will take a comma nd signal from Earth-based huma n controllers to reach them. The authors advocate the ultimate collaboration between robots and huma ns as the solution for interstellar space flight and exploration. Its a solution both inventive and futuristic, making use of future advances in biotechnology, nanotechnology, artificial intelligence, genetics and other sciences in a path lea ding to cyborgs and posthuma nism or transhuma nism. The bottom line is that huma ns are too fragile and short-lived and machines alone lack the ingenuity to solve unexpected problems.

AMNH's Space-Show Double Feature
The AMNH has launched a double feature of the museums past space shows as part of the year -long celebration of the 10th anniversary of the Rose Center for Earth and Space. The double feature is the museums first two space shows: "Passport to the Universe" and "The Search for Life: Are We Alone?" The double feature will be shown indefinitely on Fridays and Saturdays at 7:30 and 8:30 p. m. in the Hayden Planetarium (81st Street entrance). Admission is $15, $12 for museum members. To reserve tickets: 212-769-5200 or amnh. org. The current space show, "Journey to the Stars," narrated by Whoopi Goldberg, will still be shown during the da y.


Briefs: Astronomers Discover Most Massive Stars Known
Astronomers have discovered the most massive stars known, including one mor e than 300 times the mass of the Sun, double the size scientists thought hea vyweight stars could r each. These stars are millions of times brighter than the Sun and shed mass through ver y powerful winds. The discover y is the first time these hulking stars wer e individually identified. Stars were discovered inside two young clusters of stars, NGC 3603 and RMC 136a. The NGC 3603 nebula, 22,000 light-years from the Sun, is a star-making factory wher e flurries of stars form from extended clouds of gas and dust. RMC 136a is another cluster of young, massive and hot stars within the Tarantula Nebula in the Large Magellanic Cloud. Astronomers found several stars with surface temperatures mor e than 71,500 degr ees, mor e than seven times hotter than the Sun. The stars are also tens of times larger and several million times brighter. Findings suggest a number of these stars were greater than 150 solar masses at birth. Star R136a1, in the R136 cluster, is the most massive star ever found. Its mass is 265 solar masses, and its estimated birth weight as much as 320 times that of our Sun. R136a1 also has the highest luminosity of any star found, nearly 10 million times greater than the Sun. From the time of their birth, these stars produce outflows, such as powerful winds, which eventually reduce their mass. But the stars are still intensely bright. Within R136, only four of the approximately 100,000 stars found in the cluster weighed mor e than 150 solar masses at birth. Yet the intensity of their wind and radiation account for nearly half of R136s wind and radiation power. R136a1 alone emits ener gy by mor e than a factor of 50 compared to the entir e Orion Nebula. With the discover y of stars between 150 and 300 solar masses, findings raise the pr ospect of exceptionally bright, pair instability supernovae that blow themselves apart. A new radio telescope technique allows astronomers to glimpse distant reaches of the universe and could help answer such funda mental riddles as whether phenomena like dark ener gy exist. The technique allowed astronomers to observe radio light from hydrogen gas dating from when the universe was half its current age. The radio wa ves could ha ve left detectable effects on large-scale distribution of galaxies. The technique allows astronomers to measure such imprints by observing radio emission of hydrogen gas. The method, intensity mapping, could eventually revea l how such large-scale structure has changed over the last few billion years, illuminating which theory of dark ener gy is most accurate. Instead of looking for hydrogen gas in individual, distant galaxies, scientists used intensity mapping to accumula te radio waves emitted by hydrogen gas in large volumes of space, including ma ny galaxies. The new technique allows astronomers to skip a galaxy-detection step and gather radio emissions from 1,000 galaxies at a time, as well as the dimly-glowing material between them. Astronomers also developed new processes to remove ma nma de radio interfer ence and radio emission caused by nearby astronomical sources, lea ving only faint radio waves from distant hydrogen gas. Observations detected mor e hydrogen gas than all previously-detected hydrogen in the universe, and at distances 10 times farther than any radio wa ve-emitting hydrogen seen befor e. Scientists have successfully tested a new type of laser-corrected vision for telescopes that takes the widest starry-sky views ever seen from the ground while eliminating atmospheric blur. Astronomers can now see entire single star clusters or many distant galaxies in the sa me field of view. The method ca ncels out atmospher ic turbulence across a scope view about one-fifteenth the dia meter of a full Moon. Its success will likely spread to the new class of 98-foot telescope gia nts such as the Giant Magellan Telescope pla nned for Chile. The new gr oundlayer system uses five lasers. Past systems used just one to cr eate a single artificial guide star. Each laser points in a differ ent direction so they spread out in a pentagon pattern as they punch more than 15 miles into the sky. Light reflected back to the aperture is just from the lowest layer of atmospher e. Software can then adjust for the common blurry signal. Wide-view success ca me at the cost of resolution, so ima ges, while sharp, dont appear quite as sharp as those seen with traditional adaptive optics. But the tradeoff often becomes worthwhile. For instance, researchers want a wide enough field of view to see an entir e star cluster, as well as enough resolution to pick out motions of individual stars. One of the fastest big solar eruptions in years has been obser ved streaking away from the Sun at mor e than 2.2 million mph. The August 1 flare created a massive coronal mass ejection that struck Earths ma gnetic Continued on page 8
7


Briefs: New Technique May Aid Search for Earth-like Planets
Continued from page 7 field two days later, creating dazzling aurora displays. These kinds of eruptions are an early sign the S un is waking up and heading toward another solar maximu m expected in 2013. A new planet-hunting technique may be sensitive enough to help astronomers search for Earth-sized planets. The new approach, Transit Timing Variation (TTV), was used to pinpoint a planet 15 times Earths mass in the star system WASP-3, 700 light-years away in Lyra. The methods high sensitivity could also ma ke it valuable for locating small pla nets with similar masses to Earth. TTV builds on the transiting method. The new method lets astronomers further identify smaller planets whose transits might not be enough to significa ntly dent their stars light output. If smaller planets exist in addition to a large planet, the lesser ones will exert a gravitational tug on the larger planet that changes its orbit, causing deviations in the regular cycle of transits. TTV compares these deviations with predictions from computer based calculations. A violent cosmic explosion has unleashed the brightest blast of X-rays ever detected from distant space, a signal so bright it temporary blinded the NASA telescope assigned to spot it. The ga mma -ray burst quickly overwhelmed the detector when it impacted. Light from this explosion traveled 5 billion years before sla mming into Swift, overwhelming its X-ray camera. The burst emitted 143,000 X-ray photons per second during its short period of gr eatest brightness. Thats more than 140 times brighter than the brightest continuous X-ray source in the sky, a neutron star that releases 10,000 X-ray photons per second. Ga mma-ray bursts focus most of their ener gy in the short-wavelength, high-frequency range of X-rays and ga mma rays. Astronomers have found a disk of dust around a huge, massive star in its early stages of growth, indicating that stars big and small for m by the same mechanism. The star is surrounded by a disk of material similar to that around smaller, growing stars. Infrared observations of a young star about 10,000 light-years away in Centaurus found it surrounded by a circumstellar disk some 12 billion miles across. Astronomers ha ve long
8

been confident that relatively low-mass stars such as our Sun for m by gradual accretion of mass from a disk of gas and dust. They wer e less certain about stars with more than 10 times the Suns mass. Early calculations suggested solar wind and pressure of radiation ema nating from such a large star might halt infall of material from the disk, meaning for mation of massive stars would have to occur by some other mechanism, such as mer ger of sma ller stars. This is the first time scientists could ima ge inner regions of the disc around a massive young star. Data also confir med size of the circumstellar disk is related to the stars brightness the sa me wa y as with sma ller stars. When Apollo astronauts first rounded the far side of the Moon, they wer e surprised to find a bright crescent of light on the horizon at sunset. And just before sunrise, faint columns of light appeared shortly after the glow. Now a new model proposes fountains of Moon dust jet high into the sky and stay there, allowing sunlight to scatter and create glows not usually thought possible in such a tenuous atmospher e. A ver y strong electric field may kick dust high into orbit. Falling and lifting again in cycles, the dust could cr eate a temporary atmospher e that travels across the Moon with the moving boundary between night and day. Dozens of kilometer-sized moonlets in Saturns outer A ring ha ve been discovered, 11 of which have been carefully tracked for several years. Embedded in the rings, these objects might normally be difficult to find. However, their presence is betrayed by large propeller structures they generate in ring material on either side of them. Such features had been found in a different ring locale but wer e much smaller, harder to see and so numer ous ther e was no hope of following any one of them. The new propellers, and the moonlets that create them, are 10 times larger, and much easier to identify and follow from ima ge to ima ge a nd year to year. These findings will provide insight into early stages of solar -system for mation, when planets become large enough to open gaps in the ring material around them and ultimately truncate their own growth. Rocks originating deep below the Moons surface Continued on page 9


Briefs: Moon Contains Much of Common Earth Mineral
Continued from page 8 that contain rich a mounts of one of the most common minerals on Earth wer e recently discover ed around ancient impact craters. Theyr e full of olivine, thought to originate from within the lunar mantle, beneath the crust. Olivine is a silicate or rock-for ming mineral. Olivine findings had been very limited. Exposures of olivine wer e found in specific areas, in concentric rings around big impact craters, in regions wher e the lunar crust is relatively thin and the mantle is closest to the surface. Researchers suggest large lunar impacts long ago penetrated the outer crust, which exposed ma ntle olivine below the surface. Large impacts an estimated 3.8 billion-4 billion years ago likely brought olivine deposits to the surface. An unmanned probe riding a solar sail through space felt its first accelerating push from sunlight in a successful test of its novel propulsion system, Japans space agency announced. The solar sail generated the biggest acceleration through photons during interplanetary flight in history. The effect stems from the cumulative push of light photons striking the solar sail. Sunlight presses on the sail with about 0.0002 pounds of force. This is probably the next-to-last step before complete controlled solar-sail flight is achieved: turning the spacecraft to add or subtract velocity. The nearly 700-pound probe, launched in May, has thin solar cells in its kitelike frame to generate electricity. The square-shaped sail, 46 feet wide and 66 feet diagonally, is the first solar sail to fly on an interstellar mission. Photographs of enormous pits on the Moon, some hundreds of feet deep, have given scientists a glimpse into the interior. Scientists think theyr e openings to undergr ound tunnels formed by rivers of lava, similar to Earths lava tubes. Researchers speculate that the tunnels, if unclogged, could serve as passages and livable space for humans. They could offer a radiation shield and a benign ther ma l envir onment, but ma ny may have filled with solidified la va. A scorched alien planet is flying so close to its star that its atmospher e is being swept awa y in a glowing tail. The existence of the pla net and its strange tail, suggested earlier, was confir med by Hubble. Observations of the gas giant suggest strong winds from its star are blowing the atmospher e off. The planet orbits about 4 million miles from its star in just 3.5 days, yet its mass is only slightly less than Jupiters. Its atmospher e is 2,000 degr ees. Past studies suggested its losing about 10,000 tons of gas every second. Eventually, it might be stripped of its gas envelope, leaving behind a liquid cor e of lava. But it will take about 1 trillion years for the pla net to evaporate. The planet is 153 light-years from Earth. Studies have found indications of oxygen and carbon in its atmospher e. More recently, it beca me the first planet outside our solar system found to have water. Herschel has captured an image of a stellar nursery so shrouded by dust that no infrared telescope could see it until now. The cloud full of baby stars lies around 1,000 light-years away in Aquila. Infrared pictures reveal two shining regions wher e big newborn stars are causing surrounding hydrogen gas to glow. At 65 light-years across, the cloud is so dusty that until now, it had appeared only as a wall. It took Herschel, the worlds most powerful infrared scope, to peer through this haze. New measurements of Neptune's atmospher e suggest a comet may ha ve crashed into the planet about 200 years ago. Ana lyzing Neptunes atmospher e, scientists found a peculiar distribution of carbon monoxide which could indicate a comet impact. Comets lea ve their mark in atmospher es of gas giants in water, carbon dioxide, carbon monoxide, hydrocyanic acid and carbon sulfide. Herschel measur ements allowed astronomers to analyze long-wave infrared radiation of Neptune. What may be the best-preserved sma ll impact crater seen on Earth has been discover ed in Egypts Sahara Desert. The crater is pristine when compared to most meteorite-gouged holes on Earth. Many craters are partially er oded, but this one r etains much of its structure, down to rays of ejected material shot from the center when the rock hit. The crater, 148 feet wide, was spotted in Google Earth satellite photographs. Based on size a nd characteristics of the bowl-shaped crater, researchers think it was caused by an iron meteor ite 4.3 feet in diameter traveling at 7,920 mph. To verify the discovery, Continued on page 10
9


Briefs: Super-hot Blue Star Shot Out of the Milky Way
Briefs continued from page 9 geophysicists visited the site. Scientists estimate the crash occurred several thousand years ago. A super-hot blue star has been shot completely out of the Milky Way, Hubble photos reveal. Streaking at 1.6 million mph, the stars from the Milky Ways core. Astronomers think its a survivor from a triple-star system that traveled through the galaxy center 100 million years ago, but wander ed too close to the galaxys black hole, which captured one star and flung the other two out of the Milky Way. The ejected stars then mer ged to for m a super-hot blue star. Scientists traced wher e the star came from by measuring its dir ection of motion, which points from the galaxy center. Exiled stars are rare in the Milky Way. For every 100 million stars lurks one hyper velocity star. Since the first discovery in 2005, astronomers have found 16 hyper velocity stars, most believed exiles from the heart of the ga laxy. A rare specimen of massive stars that live fast and die young has been photographed. The blazing hot star WR 22 is shedding its atmospher e millions of times faster than our Sun. Its brightness allows observers to spot it with the unaided eye from mor e than 5,000 light years away. WR 22 is one of ma ny ver y bright stars in the Carina Nebula, a huge r egion of star formation in the souther n Milky Way. Two distant planets around a dying star have been discover ed locked in the closest orbital embrace ever seen. The gas giants are bound by their mutual gravitational attraction. The pair is orbiting the massive dying star HD 200964 223 light-years away. A team also discover ed two mor e exoplanets also locked in a tight embrace around another star. These planets, and the pair in the first set, are gas gia nts more massive tha n Jupiter. Members of each pair are remarkably close to one another. Because of their large masses and close proximity, the pairs exert a large gravitational force on each other. The pla nets are comparatively close to their stars. Like an earthquake in space, so-called spacequakes are temblors in Earths magnetic field caused by plasma flying off the Sun that could help generate colorful auro10

ras high in Earths atmospher e, a new study suggests. While felt most strongly in Earth orbit, the quakes can reach to the surface of Earth. Spacequakes arent the only unearthly temblors around. Scientists have also discover ed starquakes, moonquakes and asteroid quakes. Conference continued from page 1 Results from the MESSENGER mission to Mercury brought the chronology of early solar system processes for ward, to tantalizingly r ecent times. Dr. Clark Chapma n (of Southwest Research Institute) summarized new results from MESSENGER flybys of Mercury. Data indicate prominent craters such as Raditla di and Rachma ninoff have been infilled by voluminous volcanic eruptions, very much later than crater formation. Ever since the Murchison meteorite fell in 1969, organic chemists have delved into organic molecule components of primitive meteorites. The organics that are least soluble in acids are subject to intense study. The relative abundances of aliphatic and aromatic components, and their isotopic signatures, wer e the subject of ma ny presentations. Dr. Hope Ishii reported on the highest excesses of 15N found in any meteorite so far, the Isheyevo CH chondrite. Detailed study at the nanometer scale revealed these "hotspots" of heavy nitrogen are correlated to carbon-rich regions, and may involve isotopic exchange between carbonaceous material and hot water flowing through the meteor ite parent body. Organic materials in meteorites and asteroids are of gr eat interest regarding the origin of life on Earth, but so is the distribution of water in solar systems. NASAs ma ntra has been "follow the water," with spectacular success in the Mars Exploration Rover and related orbital missions. Dr. Andr ew Rivkin (Johns Hopkins) reviewed recent findings of water ice in the spectra of main-belt asteroids, particularly the low-albedo (dark) kind. This work is leading to a more r efined taxonomy of asteroids based on their spectra (how they reflect sunlight into our telescopic spectrometers). AAA member Denton Ebel is associate curator in the Department of Earth and Planetary Sciences at the AMNH. He was the prime organizer of the conference.


Events on the Horizon September 2010
M: me mbers; P: open to the public; T: bring your telescopes, binoculars, etc.; C: cancelled if cloudy; HQ: at AAA headquarters, Downtown Community Center, 120 Warren St. AMNH: For ticket information, call (212) 769-5200 For directions to AAA observing events, check the club's website, www.aaa.org. Thursday, September 2, dusk-11 p. m. Movies with a View, Pier 1, Brooklyn, P, T Learn to operate an 8-inch Dobsonian scope and watch a free movie. Info: http://www.brooklynbridgepark.org/go/ p r ogr a ms -/ -ev ent s / mo v i es - wit h-a -v i ew. Saturdays September 4, 11, 18, 25, evening Observing at Inwood Hill Park, Manhattan, P, T, C Next dates: Saturdays in October. Tuesdays, September 7, 14, 21, 28, dusk-9:45 p. m. Observing at the High Line, Manhattan, P, T, C Next dates: Tuesdays in October. Wednesday, September 8, 8:30-10 p. m. Observing at Fort Tryon Park near The Cloisters, Manhattan, P, T, C Next date: October 13. Saturday, September 11, dusk Observing at Great Kills Gateway National Park, Staten Island P, T, C Next date: October 9. Saturday, September 11, dusk-10 p. m. Observing at Fort Greene Park, Brooklyn, P, T, C Rain date: September 18. Next date: October 13. Saturday, September 11, dusk. Observing S out h Lake, Gre e ne Co unty, M, For directions: http://aaa.org/northsouthlake Rosenberg at 718-522-5014, Rain date: Sept Next date: October 2. at NorthT, C or Rich ember 18. Wednesday, September 15, 8-11 p. m. Observing at Prospect Park, Brooklyn, P, T, C Last session in 2010. Thursday, September 16, 6:30-8:30 p. m., 726 Broadway, sixth floor conference room. Recent Advances in Astronomy Seminar, M The seminar now incorporates the Observers Group. Next date: October 14. Friday, September 17, 8-10 p. m. Observing at Floyd Bennett Field, Brooklyn, P, T, C Next date: October 15. Saturday, September 18, 4 p. m. thru ear Fall Equinox Festival, Pier 84, Hudson Street, P, T A celebration of the autumnal equinox. entertainment, a talk about the equinox, night astronomy. ly evening River at 44th Ther e will be and solar and

Monday, September 20, dusk to 10 p. m. Observing in Rego Park, Queens, P, T, C Rain date: S eptember 22. Next date: To be deter mined. Monday, September 20, 7:30 p. m. Hayden Planetarium Lecture, P, AMNH University of Arizona astronomy professor Chris Impey, author of "How It Ends," will explor e endings, from the proximate to the distant. Friday, September 24, dusk-11 p. m. Observing at Carl Schurz Park, Manhattan, P, T, C Next date: October 15. Saturday, September 25, 10 a. m. to noon Solar Observing at Central Park, P, T, C At the Conservator y Waters. Next date: October 30.
11

Tuesday, September 14, dusk-10 p. m. Observing at Cadman Plaza, Brooklyn, P, T, C Next date: October 5.


Viewing continued from page 4 of the planetarium and one of the few prominent black Amer ica ns in astronomy. Having a guide to the southern sky was great. Sam rolled out a 12-inch Celestron Schmidt-Cassegrain telescope. The trail of the Milky Way stretched across the sky, despite various lights on the buildings and antenna e. I saw stars and constellations we cant see in the northern sky. We traded various objects: Souther n Cross (south), Big Dipper (north), Magellanic Clouds (south), Orion (north). It was darker at the observatory tha n at the b&b, so I managed to get nice photos of the faint Milky Way and the 26-meter radio antenna. Sam asked what the crescent Moon looked like wher e I live. I told him the crescent was either on the left or right side. A few days earlier, as I photographed the Moon setting with Venus from outside the b&b, I saw that the cr escent was mor e towards the bottom, ma king a U-shape. During a recent alignment of the Moon, Venus and Jupiter, Sam said, the trio ma de a "face" since the Moons shape was upturned like a smile. Although the observing session was short and it was cold, it was a great experience.

AAA Featured on NY1
The AAA continues to create mor e buzz, especially our High Line observing sessions. TV station NY1 ran a feature on us the weekend of August 7-8, emphasizing our appeal to youngsters. You can see it at http:// www. ny1.com/content/123287/young-stargazers-peer-athea venly-spher es-from-the-high-line. Reporter Shazia Khan was so taken with us she promised to come back. To get to the High Line, a former elevated rail line that opened last year, take one of the many subway and bus lines to 14th Street in Manhattan. Get on the 14D bus to 10th Avenue. Across the street ther es an elevator to head up to the High Line. Go south a short distance and you should see us on Tuesda ys this month from dusk until the park closes at 10 p. m. ­ Richard Rosenberg

Contacting the AAA
General club matters: president@aaa.org. Membership business, such as dues and cha nge of address: members@aaa.org. Eyepiece: editor@aaa.org. Lectures: lectures@aaa.org. Classes: classes@aaa.org. Seminar: seminar@aaa.org. Observing: president@aaa.org. Please visit us on the web at www.aaa.org.

Amateur Astronomers Association Gracie Station P. O. Box 383 New York, NY 10028

Forwarding and Address Correction Requested 12

First Class